# Megasquirt Over Run Settings, Boost, Ring Failure



## fakename (Apr 5, 2012)

I'm suspecting that I've burned up my rings on my 16vT. I came across a post while searching where weeblebiker (member on here) mentioned something about how he wondered if his ring failure had something to do with his over run settings in megasquirt. Thinking about that, I think that I can correlate the time I started noticing oil consumption problems (among others related) with when I tuned my over run settings to cut fuel after 1 second of off-throttle. Before that tuning, my over run setting would never kick in.

Anyone have experience with this?


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## need_a_VR6 (May 19, 1999)

Over run should literally do nothing, as it fully cuts fuel on decel. 

What are your compression and leakdown numbers?


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## fakename (Apr 5, 2012)

hmm... Ok, I thought maybe the lack of fuel would contribute to rising chamber temperatures particularly after big pulls.

I haven't performed a leakdown test but my compression reads 180, 190, 210, 180 on a stock 9A with 2 new ABA gaskets. HERE is a link to a different thread that I started with more information about my situation. But to summarize, probably about 4 months ago I swapped heads with a cleaned, decked, head with a valve job and new seals, new head gaskets. And about a month ago I noticed oil going the way of the dodo and saw it leaking from the HG and noticed it burning it too, then it started fouling plugs with every drive. Over the weekend I replaced the head gaskets but alas, it's still fouling plugs. ...with oil.


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## need_a_VR6 (May 19, 1999)

If anything it will cool more as you're just pumping air through the engine.

New head on the car and now oil issues... I would look into the head. Could easily be a seal or guide gone bad. I have seen enough bad work that it wouldn't be a surprise at all. 

Do you see oil in the exhaust at any time? Cold start? Decel?


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## fakename (Apr 5, 2012)

Well I was the one who put the head back together so bad work is certainly a possibility, it was my first time doing it. But it seems like I couldn't really screw up putting those valve seals in, kinda just one way to do it. And the valves didn't have any play in the guides so I figured it was all in good shape.

I have seen smoke through the exhaust at start up and when I stick my foot in it, primarily.

Oh, and I will mention that when I replaced the head, I also pulled the pistons because I had some forged low comp pistons I wanted to put in the block. Turned out they were the wrong size so I put the stock ones back in but reused the old rings. Don't know if that's helpful info or not...


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## need_a_VR6 (May 19, 1999)

Comp numbers are good, if not high for that setup. Worth doing a leakdown to see if you hear anything out of the valve cover breather while doing the test. You can still have good comp but oil problems if the oil control ring got damaged on re-install. Generally top end problems will be on cold start and decel, bottom end problems on cold start and accel. Do you have a catch can on it or are recirculating into the intake?


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## fakename (Apr 5, 2012)

That's what I thought about the compression numbers. Before I swapped heads, it was around 145 across all 4 which seemed about right. With a valve job I assumed they would seal better so my numbers would go up at least a little, and the head was decked so that might increase compression a little too. But 180 surprised me not to mention 210 (on my most problematic cylinder)! Which makes me think that since they're high, the valves are sealing well but my oil rings are toast, letting oil get onto my compression rings and increasing their seal, while letting oil in to get burned.

I do have a breather setup and it goes to a catch can, doesn't fill very quickly at all so I would think stem seals are good.

Can rings successfully be reused, or is that usually not done? I know it makes sense to replace them with new rings if the pistons are already out, but curious if it's 'bad engine etiquette' not to replace them.


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## the_mad_rabbit (Aug 10, 2003)

fakename said:


> I'm suspecting that I've burned up my rings on my 16vT. I came across a post while searching where weeblebiker (member on here) mentioned something about how he wondered if his ring failure had something to do with his over run settings in megasquirt. Thinking about that, I think that I can correlate the time I started noticing oil consumption problems (among others related) with when I tuned my over run settings to cut fuel after 1 second of off-throttle. Before that tuning, my over run setting would never kick in.
> 
> Anyone have experience with this?


Blew a chunk of ringland with my aba-T on MS 2 3.57. Direct result of too much timing, but I like to live on the wild side and tear apart my motors every 6 months . 
Given what you've said though, sounds like there's an issue with the head. Leakdown test time!

And... get rid of that double-stacked headgasket nonsense! You have MS! Just pull some timing and be on your merry way! Plus, you REALLY shouldn't be running stacked HG's when turbo'd...
-AJ

edit:


fakename said:


> That's what I thought about the compression numbers. Before I swapped heads, it was around 145 across all 4 which seemed about right. With a valve job I assumed they would seal better so my numbers would go up at least a little, and the head was decked so that might increase compression a little too. But 180 surprised me not to mention 210 (on my most problematic cylinder)! Which makes me think that since they're high, the valves are sealing well but my oil rings are toast, letting oil get onto my compression rings and increasing their seal, while letting oil in to get burned.
> 
> I do have a breather setup and it goes to a catch can, doesn't fill very quickly at all so I would think stem seals are good.
> 
> Can rings successfully be reused, or is that usually not done? I know it makes sense to replace them with new rings if the pistons are already out, but curious if it's 'bad engine etiquette' not to replace them.


145? That seems very low unless you have some low comp pistons in that motor. I'm around 215/220 across the board with my ABA motor that should clock in around 9.8:1 CR. In comparison, 7.8:1 CR ~ 120 with a stock 1600 Bug motor (at sea level).
I wouldn't ever re-use rings. Chuck them and install new ones. Do a quick hone to de-glaze the cylinder walls and use plenty of WD-40 when honing. Tape off the conrod journals if you're doing this without pulling the motor and cover the crank with towels. 
And, no. Do not just throw rings into the motor without doing a quick hone. The rings will not seat properly.


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## fakename (Apr 5, 2012)

I realized that since I've been burning oil, my over run settings were keeping that oil from being burned on deccel and fouling my plugs. Once I turned over run off, I could drive it. Still drove like **** but I could make it from A to B.

Thanks madrabbit for the input. I've disassembled and got new rings in there now (after another hone) so we'll see when I put it all back together today or tomorrow. There was a fair amount of carbon on the oil control ring grooves in the pistons but visually the rings didn't look like there was anything wrong, although I don't know if I would necessarily know by looking. The tension of the old control rings against the cylinders was substantially less than the new ones so maybe the old ones were weak and couldn't seat? New rings, fingers crossed.

I have most of the head apart now too and the seals look good, guides still feel solid-no play with the valves. I can't see any red flags with the head so I think I'm just going to put it back together as is.

I've never considered running a single gasket with stock internals, I always thought that was not recommended. But I'll admit I'm not a tuning guy particularly on the parts of my maps that could destroy my engine if I do something stupid. Here's a pic of my ignition map. Any thoughts?


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## the_mad_rabbit (Aug 10, 2003)

Cool beans. I knew someone running 14psi of boost on a volvo distributor and all CIS boost related stuff a good 10 years ago. Pretty much DIY oldschool turbo setup. Daily driver, never blew a HG, stock internals. VW motors are pretty robust. With that said, don't believe everything you read online unless there is hard evidence :laugh: 

My table on MS2 3.57 (should be latest update on firmware/software on tunerstudio). Setup: 63/60 Stg3 turbo, Siemens Deka 80lbs injectors, bosh 4 window hall distributor, cammed, stock bosh coil, stock AIT, bosh wideband with MTX-L gauge, and some other stuff 



Remember, all motors are different and no two are alike. With that said, you timing table looks a bit... aggressive. I had to pull 2 more degrees out of the timing from 1400-3000 rpm from 81-116 kpa because the em-effer still pings! Running cool sparkplugs too... everything else on the upper end is currently set to conservative until I get around to going to the dyno.

And, any reason why you're running 15 degrees at 1000rpm? Again, that seems... VERY aggressive. With that said, your table looks a LOT like my old table that resulted in a blown ringland...

-AJ


p.s.: before you put the head back on the motor, since you are so far, if possible... lap the valves! Or, at least take a look at the valves and seats to make sure they're not hammered.


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## fakename (Apr 5, 2012)

Thanks for posting your table, certainly looks smoother than mine. The 15 at 1000rpms and 25 below that were adjustments I made to help cold start idle and full temp idle be within a hundred or so rpms of each other. And 15 at 1000 just seemed to idle the smoothest, maybe because my cams are a little lumpy down low?
With the stacked gaskets I think I am around 8.5:1 or 9.0:1 (?) and have seen other timing tables really similar to mine with the same compression. I think it definitely would be aggressive if I only use one HG and bring it back to 10.0:1. I'm still doing research on just one head gasket and because I daily this I think it might be safer to just run them both. I'd rather blow headgaskets than rebuild from detonation. But we'll see after some more searching. What compression are you running with that timing table?

I haven't put the head back on yet, I pulled some of the valves and checked the seals and guides and they looked good. But after I put it back together, I decided that I should take the time and properly wire wheel the carbon off of the faces of the valves before I reinstall it. Burning all that oil has caked a couple of them pretty badly. They did have a valve job only 6 months ago though and all the seats and valves edges still look good.


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## the_mad_rabbit (Aug 10, 2003)

fakename said:


> Thanks for posting your table, certainly looks smoother than mine. The 15 at 1000rpms and 25 below that were adjustments I made to help cold start idle and full temp idle be within a hundred or so rpms of each other. And 15 at 1000 just seemed to idle the smoothest, maybe because my cams are a little lumpy down low?
> With the stacked gaskets I think I am around 8.5:1 or 9.0:1 (?) and have seen other timing tables really similar to mine with the same compression. I think it definitely would be aggressive if I only use one HG and bring it back to 10.0:1. I'm still doing research on just one head gasket and because I daily this I think it might be safer to just run them both. I'd rather blow headgaskets than rebuild from detonation. But we'll see after some more searching. What compression are you running with that timing table?


:thumbup: - Did you buy tunerstudio so you can run the live analyzer? It can auto-tune the cold start. I'm not running a stepper motor to the throttle body or an ISV so my car idles a bit low when cold, then a tick high when warm, but nothing too crazy. 
Just a side note, any motor can blow up with too much timing, be it at 8:1 or 13:1, boosted or not. 

I'm at 9.8:1 CR with that table and should be good for about 15-18lbs of boost. Generally speaking you want to take out as much timing as possible- so, a "safe" table/"dummy mode" table. Then drive the **** out of it with live analyzer running to build your fuel tables. Want to get the fuel tables built for the amount of boost you want to run and the max RPM you will revv the motor. THEN, after you do that, it's time to go to the dyno. Do a pull, check what power you made, add timing, do a pull, check what power you made, wash rinse repeat.

You add timing until the motor stops making power/the curve drops sharply (it will increase dramatically at first, then taper off quickly once you are getting to the maximum amount of timing that you can run), then you pull 1/2 a point to a point worth of timing (to play it safe and keep the motor healthy), and you're done. 

Really, to properly do timing tables you need to go to the dyno.

Cheers

-AJ


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## fakename (Apr 5, 2012)

Thanks for your last post. I've been pretty bogged down the past few days to reply. I have the free version of TS but I think I'll buy the real deal and figure out how to autotune.

But here's where I am now. I've reassembled the engine (put two gaskets back in, just to be safe). I got it to turn over but it was running pretty ****ty and wouldn't hold an idle. I drove it around to full temp and then put my foot in it a few times trying to seat the rings properly even though it isn't running great. So anyway, now I'm trying to figure out why it's running 'rich' throughout the rev range but dying at idle. I'm wondering if I've damaged my o2 sensor with all the oil that was being burned and now it's running ****ty as a result? I rechecked all my mechanical timing, I'm pretty good about placing the distributor back in the same position but couldn't check with a light because it won't idle at all, wires are 1342.

I'm wondering if my o2 sensor is damaged and reading rich, MS is correcting and I'm running lean as a result? Not sure if megasquirt uses my afr's to adjust in real time, seems like something I should know... it's MS1 by the way.

Any thoughts?


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## need_a_VR6 (May 19, 1999)

Go to ego menu and turn % correct to 0. Try again. 

Check the basics, cam timing, ignition timing, sensor readings etc


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## fakename (Apr 5, 2012)

Checked my tune and apparently controller authority % has always been set to zero. So it's not that. But now I can't get TS to recognize my ecu 'not connected' and when I turn the car off and on, I get no lights on my ecu. I vaguely remember not ever having lights on startup but now I'm not so sure. hmmm... TS has latest firmware update, not sure about MS and I don't have a stimulator, opened the case and nothing looks/smells like it's fried or damaged. It's raining really hard right now so I haven't checked my cam timing yet but I'm about to. Last night I checked and TDC on my cam sprocket lines up with TDC on my flywheel. Would one/two teeth off between exh./int. cams have this effect? Assuming I didn't bend any of my valves already...


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## fakename (Apr 5, 2012)

Sure enough, intake cam was one tooth off, about to compression test to verify no valves got whacked. Also noticed the plug wire that connects to my coil was really corroded on the inside so I cleaned that out, will do the same with the inside of the coil: an on going problem I always forget about. No idea how it corrodes though, plug is air-tight on the coil so I wouldn't imagine moisture would get in...
Anyway, car fired up, runs well but still hesitates a similar way it did before I started working on it. I thought it was initially doing that because it was burning a lot of oil which it doesn't appear to be doing now. Maybe a little as the rings seat? About to compression test, change oil/filter, and check plugs.

**

Compression is exactly 180 on all cyliners, plugs looks perfect, oil pressure is good. I think the engine is in good shape! But it still stumbles and hesitates like it used to and occasionally dies (I have reset my ignition timing). I thought it might be the hall sender so I've swapped in a different distributor that I had and same problem. I took a datalog while driving but rpms didn't dip out on that run. Not sure why it's hesitating...


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## ps2375 (Aug 13, 2003)

It hesitates when? When you tip in the throttle? You need to get your tune right(Ve table) and also get your accel enrichment's set, are you using MAP or TPS based enrichments?


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## fakename (Apr 5, 2012)

It hesitates during accel but even just when cruising, and occasionally I randomly lose spark, sometimes just for a second (rpms drop to zero and jump back up) or I will lose spark and it will die. In those instances I can usually just cycle the key and pop the clutch and it's back. Which makes me think that there is a problem beyond my tune, does that seem logical?

I just registered tunerstudio so I'm going to drive around with the live analyzer. I'm just going to use the table generated by TS, sound like a good idea? I tuned my accel enrichments a few months ago but I suppose if I was burning oil then, that would screw up my settings. Should I set my accel enrich to zero while I use the live analyze?


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## need_a_VR6 (May 19, 1999)

Take some logs first look for sync or power loss. If none look for lean spots that could be ignition troubles.


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## fakename (Apr 5, 2012)

The values on my AEM 30-4100 aren't the same as what tunerstudio is reading but I found this thread and this thread so I'm changing that now and if it works, then I'll try the live analyzer.

I took a few datalogs and captured a couple of events. Can I load datalogs here? I took a few screenshots:




























No sync loss problems. Any ideas? Just to reiterate, I'll be driving and randomly rpms will drop. Either they will (1) jump right back and it'll keep driving, (2) they will jump up to around 1000 and hold there for a second or two and then jump back, (3) rpms will drop and I'll have to pop the clutch to kick it back, and lastly (4) rpms will drop and I'll have to pull over and let it sit for a minute or so before it will fire up again. And it just seems to run a little rough overall.


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## need_a_VR6 (May 19, 1999)

What are you using for a trigger?


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## fakename (Apr 5, 2012)

Hall sender off my distributor. Previous distributor's hall sender plug broke but could still be held in place to work, thought maybe it was creating a bad connection so I have another distributor/sender on there now with no change. 2nd dist was not new and I don't know the history of it but was told it was pulled from a running car.


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## need_a_VR6 (May 19, 1999)

Try and take a trigger log while making the problem happen. Looks like you are losing tach pulses or there is noise.


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## fakename (Apr 5, 2012)

Just looking into tooth logging now, never done it before, seems straight forward. A few years ago I ran into noise after installing a new fuel pump and relocated my grounds to my head as well as soldering a few jumper wires on the bottom of my ecu (as recommended) and that cleared it up. Haven't installed/wired anything new since then.

Is noise typically a ground issue? MS grounds looked good when I removed the head, maybe I'll just go through and clean all my grounds anyway.

What might cause me to lose tach signal if my issue isn't noise?


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## fakename (Apr 5, 2012)

I opened up my ecu and saw this tab hitting one of the things (I don't know what anything is called):









Then while it was plugged in and running, the tab hit either the pin or something, small spark, car shut off, now I think my ecu is dead. Nothing smells or looks smoked but now when I cycle the key it won't prime the fuel pump, won't start, and it isn't recognized in TS 'not connected'. Any ideas what may have happened or if I can try to fix it myself? Vederin is local, I can probably send it to him but I'd rather not have to.


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## need_a_VR6 (May 19, 1999)

Ok thats the 5v regulator. Pins are 12v 5v and ground. Remove the offender and power it up and see where you get power and where you don't. May have popped one of the protection diodes. Schematics are on megamanual.com and msextra.


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## fakename (Apr 5, 2012)

Oh phew, doesn't sound as catastrophic as I thought! Thanks, I'll check those values.


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## need_a_VR6 (May 19, 1999)

As long as there isn't an internal board short, it's fixable.


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## fakename (Apr 5, 2012)

Well, all I did was blow a fuse. Feel like a dummy for not looking there first :facepalm:. Haven't had a chance to run it again, just need to get another 5A to replace it with, but tested it with a spare 15 and all is well. Now I'll get back to the misfire issue. By the way, I started a thread about this on msextra here just for reference. Before I blew the fuse, I went through and cleaned all my grounds. I also tried taking tooth logs but think I might be doing it wrong. Below is a screenshot of page 1/15 but they all look the same:










Other than that, I haven't checked much. Can't remember exactly where I was in the process, past few days have been hectic. Actually wondering if that tab for the serial connector may have been messing with my ignition stuff. Sure would be nice if that solves all my problems :screwy:

More questions to come come. Thanks again for all your help so far Paul.


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## fakename (Apr 5, 2012)

Truth is that I don't know if it's even a megasquirt issue, I'm trying to think on the periphery. I wonder if a clogged up catalytic converter could be part of my problem? I had been burning oil for awhile and wonder if it is clogged from that. Going to look into it further.


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## the_mad_rabbit (Aug 10, 2003)

I don't have a MSextra account.... so, on Graph 4, tick "Lost Sync Count" and for the 2nd one "Lost Sync Reason".

Lost sync reason will give you a "max" value which can be decoded. Think of it kind of like a port scanner for errors. Post here what you find there. If max = 2, then I'll proceed to chuckle and drink some Macallan over rocks while listening to Beethoven on Vinyl.

Cheers

-AJ


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## fakename (Apr 5, 2012)

hmm... I don't have those option in the pulldown menus, it's MS1 so it might not be available to me. But don't let that ruin your plans, Beethoven on vinyl is the only true way to hear it, otherwise you're just selling out. What does reason max=2 mean?

This is a hard one to test because it's intermittent. I let it run today until it died and then tried to test it while it didn't want to start again. While cranking, no spark output led light on the ecu, bip temp isn't noticeably warm. With key on, I'm getting 4.5V+/- to my hall sender plug (red wire?) and ground is good, and getting 12v to coil.

So since MS isn't sending spark signal, I'm trying to test from the hall sender back to the ecu to see where the problem is. Any other suggestions of what to test? Thanks.


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## need_a_VR6 (May 19, 1999)

Did you have rpm when you lost spark? If you aren't using all the leds you can set one to irq trigger and see if it flashes while cranking.


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## fakename (Apr 5, 2012)

Oh, I didn't know about that option. Thanks! Just to clarify, the LED will flash if the ecu receives a signal which in my case would be from my hall sender? So if it isn't starting but it's flashing, probably a problem inside the ecu. If it's not flashing/not starting, probably a problem before the ecu? And I am not seeing rpms during cranking.


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## need_a_VR6 (May 19, 1999)

No cranking rpm is an input issue.


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## fakename (Apr 5, 2012)

Oh, I thought that MS got the same rpm signal that the tach on my cluster gets from my coil. Wow, that is good to know! And I'm just now reading this from here:

The hall sensor requires a supply voltage which is usually 12V from a fused 12V supply or 5V from the TPSREF output of the Megasquirt. The sensor is then grounded at the Megasquirt and _the third wire connects to the tach input.
_

So if that's the case, my problem must be my hall sender or my wiring and since it's the second hall sender I may just have a short somewhere. But what I still can't figure out is why it would then start again after I let it sit for a few minutes...


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## the_mad_rabbit (Aug 10, 2003)

Error 2 on MS 2 or higher = missing tooth at wrong time

http://www.msextra.com/forums/viewtopic.php?f=101&t=40575

I had this issue in my micro-squirt corrado where at specific RPM's I'd lose RPM signal, causing all kinds of fun stuff to happen (mainly, a massive miss followed by plumes of smoke from unburnt fuel). I also had an issue with my MS2 Jetta where I'd fire the car up, it would run for a few seconds, then shut down. Same thing- RPM signal loss. Didn't do anything except change some of my wiring and then the damn thing wouldn't start anymore...

Microsquirt Corrado needs a 1-2k ohm resistor across VRef+ and VRef- to clean up the noise. The Jetta needed the firmware to be completely re-flashed on the unit itself (It's using a modified 4 window hall sensor style pickup, the same as your 16v).

I would say... why not try re-flashing your MS1 with the most recent code (it IS constantly updated) and re-loading your current tune to see if that helps. If you're using a Hall sensor style signal, it's pretty unusual for you to lose signal... unless you have a bad ground somewhere or the ground from the chassis is incorporated into the sensor ground (which is a no-no). If they are, you'll end up with a bunch of input noise that can wreck havoc.

-AJ


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## need_a_VR6 (May 19, 1999)

If you are running fuel and spark ms is triggered by the hall and then the ms fires the injectors and coil. If you are fuel only you can trigger from hall or the coil. Not sure exactly how you are set up.


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## fakename (Apr 5, 2012)

I see, I'm fuel and spark so it must be straight from the hall sender. But it sounds like if it isn't 'seeing' the signal from the hall (or seeing it intermittently) it could still be an issue with the ecu. I was thinking it was a little more conclusive, that my problem is probably in front of the ecu but that might not be the case, if it's anything like what AJ was experiencing. I was having problems with noise a couple of years ago after I upgraded my fuel pump, I will see exactly what I soldered but I added resistors? Caps? I don't know, big green things in specific places and it ran better without drop outs. I'll check what they are and see if those are the same as what you installed AJ.

Truthfully, I've never reflashed my ecu before. Found this with a step by step. I'll give that a shot.


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## need_a_VR6 (May 19, 1999)

You can tap the trigger wire to ground and see if you get rpm. If you get it, that would mean the hall is bad.


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## fakename (Apr 5, 2012)

I'll try that when I get a chance. In the mean time, I'm trying to update my firmware with these instructions but after I do the 'update the INI/ECU definition file' I get this error:










Then it asks if I would like to update my controller econfiguration file. The only file I can see is the msns-extra.ini file but clicking on that one gives me the same error. Is it a different file it's looking for?

*System restore cleared whatever I screwed up so now I can load my project. Not sure how I'm screwing up this firmware flash though.
*Think I reflashed it properly. Haven't had time to run/test it.


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## the_mad_rabbit (Aug 10, 2003)

need_a_VR6 said:


> You can tap the trigger wire to ground and see if you get rpm. If you get it, that would mean the hall is bad.


Or, you can pull the dizzy off, ignition switch on, pull out one spark plug wire and throw a plug in there, then turn the dizzy over by hand to see if you get spark. It's super rare that VW hall sensors go bad. I've yet to see it personally. I won't say that they DON'T go bad, but it's pretty rare.

-AJ


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## fakename (Apr 5, 2012)

I am also skeptical that the hall sender is the problem just because I've tried it with two different senders/distributors and the problem doesn't change. I'm going to unwrap my harness going from the sender to my ecu and check it out but assuming it all looks good, I'm going to look into the tach input circuit on the ecu and try to trace it.

Here are a couple of photos of jumpers on my ecu:



















I'm noticing some wiring that doesn't seem to match the install steps, I'm listing them here for my own reference but if any of my wiring makes sense to you guys, please let me know why:

I'm looking here and noticing that I don't have a 1k resistor inline from optoin to 5V in the proto area.
I don't have a jumper from xg1 to xg2.
Found a post from Matt Cramer "Jumpering XG1 to IAC1A would make pin 25 a tach input" which is how my board is wired. So what does that make pin 24?
"If you have a Hall sensor or optical sensor, *do not install D1*, put a jumper in its place." Same step says roughly the same thing about D2 but says it's ok to solder the diode and jumper between it's leads essentially shorting it out. This is how both D1 and D2 are wired.
"If you later find you have an intermittent tach signal on the vehicle, but it doesn't work at all speeds or all temperatures in the car, check the Hall circuit modifications here: Hall input circuit mods"


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## need_a_VR6 (May 19, 1999)

Does the jumper to 5v with the resistor go to tachselect or opto in? Is there any other jumper from either optoin or top c30 to 5v with a resistor?


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## fakename (Apr 5, 2012)

Only jumper with a resistor inline goes from IGBTIN to R26. TACHSELECT has a short jumper to OPTOIN and a long jumper between both of those to +5v but doesn't have a resistor.


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## need_a_VR6 (May 19, 1999)

Hmm d1,d2 and r13 jumpered?


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## fakename (Apr 5, 2012)

I don't have the board in front of me, I'm fairly certain that R13 has some type of component, I assume resistor, and I know that D1, D2 have diodes installed on top of the board but on the bottom of the board, each diode individually has a jumper from one of it's leads to it's other lead.


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## need_a_VR6 (May 19, 1999)

Ok those mods put 5v on pin 24 (used for hall power most likely) has the hall pullup in r13 (1k?) and the hall signal coming in on pin25. I have never seen these mods on a v3 but a similar method was used on v2.2 boards for a long time before everything was standardized.


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## fakename (Apr 5, 2012)

You're right! Matt on msextra said the same thing, I don't know why my board is wired this way. He suggested that I clean the bottom of the board with alcohol so I did. It's still having these random events but the nature of them has changed, I've got a new datalog, don't know how to upload it here but here is a screenshot:










The single red lines are resets and the double red lines are 'going offline' and they always happen in pairs. It wasn't doing this before tonight. If the rpms are above idle, it seems to recover before it stalls, if it's idling, it generally stalls when this happens. In either case, I can hear my fuel pump relay click on and off at the same time as I lose connection with my computer and the ecu. When it stalls, fuel pump kicks off immediately and then a few seconds later it kicks on, pump primes, and then it kicks off again. The relay has not had this behavior until tonight's test drive.

Any thoughts?


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## need_a_VR6 (May 19, 1999)

Looks like you are losing 12v to the ecu or losing 5v power inside it.


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## fakename (Apr 5, 2012)

Any suggestions of what to test? I'll test my relays but once I've got the ecu open, any direction will be helpful.

I think I understand that it could also be processor resets causing me to lose power momentarily-that the power losses are a symptom, not a cause. And these usually come from noise? Last time I was dealing with resets I feel like I made quite a few noise reduction mods by adding capacitors (I think they were caps?!?) and it went away.


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## fakename (Apr 5, 2012)

Tried for another test drive today and I'm back to losing trigger signal (confirmed with the led not flashing-thanks for that tip Paul!). My battery died shortly thereafter which surprised me. I was cranking it over a fair amount but didn't seem like enough to kill it.

I'm going to check the schematics but looks like since I'm using pin 25 for 'tach in' I should look at what would typically be wired in for an IAC circuit. On to do some more research!


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## fakename (Apr 5, 2012)

I removed the capacitor that I added awhile ago to pin 6 on the processor (to help combat noise resets) and the car ran again although it was still resetting. I replaced it with a new .1 uF cap and haven't gotten a reset since and it runs much smoother.


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## fakename (Apr 5, 2012)

Update, car is continuing to die on me randomly and I'm having trouble getting connection to my computer, think it might be my serial-usb or it might all be related. (Hope I'm not just talking to myself at this point...)

Testing recap:

When car dies I get no leds for spark output or IRQ trigger during cranking.
I've shorted my 'tach in' to ground at my hall sender plug and I get a spark.
I've tried with different hall senders.
Voltage at hall plug is 4.2V for tach in, and 4.95v for hall power.
Grounds have all been checked and cleaned. Harness looked over for shorts.

Car died on me yesterday, couple hours later it started and I limped it home. Let it sit and idle for 40 minutes while I messed about testing, never died on me during idle. May need to be under load?

I feel like I'm at a loss, everything seems to check out during testing, unless something like my processor dies and then when I go to test it, it's working again. I don't have a stimulator but thinking I should get one.

Help me Obi Wan...


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## need_a_VR6 (May 19, 1999)

If you can solder, reflow all the joints on the tach input circuit and 5v section.


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## fakename (Apr 5, 2012)

Ok, I think I know the tach in circuit. Would the 5v section begin at the voltage regulator and then just try to follow it all the way around?


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## fakename (Apr 5, 2012)

Haven't resoldered anything yet, got sidetracked. Drove around the neighborhood till it died, pulled over and wouldn't start but this time I was getting spark. Tested my injector wires and found continuity between ALL OF THEM? What? Am I crazy or does that not sound right? Key on, there is 12v going to both wires for each injector, shouldn't one of those be for ground switching? Disconnected the db37 from the ms and still got continuity between every wire at the injector plugs, even from one injector to the other (ones not paired together). Is that how it's supposed to be?


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## ps2375 (Aug 13, 2003)

The MS is a "Ground switching" device, so yes you will have 12Von both sides of the injector until MS completed the ground, then you will have 12V on one and ground on the other.


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## fakename (Apr 5, 2012)

Thanks, I realized my mistake thinking I would read a ground signal.

I resoldered a few points last night, replaced a jumper, and tested 5v on pins 1,20,31 against grounds at 2,19,32, everything checks out. I'll test drive it today.

I'm going back to the basics and testing my ignition components again. I'm using an msd blaster 2 coil and seeing that impedance is higher than spec when I test the center tower and the negative terminal (5.5k instead of 4.5k). I have a backup coil lying around that tests within spec so I'll swap that in. Corrosion is an issue for me inside the center tower on my coils, not sure how to prevent it.


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## fakename (Apr 5, 2012)

I have 12v at my coil on both pos and neg terminals. When I ground my tach in wire at my hall plug, voltage on the neg terminal drops to 3v and takes a second or two to creep back to 12v. Pos terminal drops to 9v then creeps back to 12v. Spark is intermittent, leds flash consistently on ecu during cranking, when I see spark it is orange and weak, fouled plugs with fuel on first crank. Cleaned coil center and plug ends, plug wires are within spec.

*I can get a weak spark by grounding the coil plug wire to the head but once I plug it back into the distributor cap, I get no spark from a grounded plug through the other wires. I tested with an older rotor and cap with same results.


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## fakename (Apr 5, 2012)

Any other suggestions to test? I'm drawing blanks here. Recap:

IRQtrigger and spark output leds flash during cranking with intermittent/weak spark direct from coil, no spark at spark plugs. Voltage in ecu checks out with the exception of 11.5v at left pin of U5 (is that normal?), coil/wires are within spec and coil fires when wired directly to battery. This has developed from my initial issue of having no hall signal to ecu which appears to be fixed.

I'm at the point where I might just start throwing parts at it but if I fix it like that, I'll still feel like I failed. i wouldn't even know what parts to throw! Everything tests in working order. Have a feeling my issue is somewhere in the ecu.


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## ps2375 (Aug 13, 2003)

Are you sure the MS unit is working correctly?


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## fakename (Apr 5, 2012)

I am definitely not sure of that. Do you mean like a failing processor? It's been "working" up until now, ish...

Side note: I found this thread about how a firmware update was incompatible with his tune settings, in particular, that some part of his source code had really low dwell time and his changes in TS didn't affect it. I updated to 029y4 last week (don't remember what the old firmware was) and am wondering if I have a similar issue, low dwell I think would certainly be a source of my not getting spark.


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## need_a_VR6 (May 19, 1999)

That can happen, what firmware were you running before? If you suspect this, go to your old msq and export the fuel and spark maps and reflash the code and change all the settings by hand.


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## fakename (Apr 5, 2012)

I wish I knew what the old firmware was but I have no idea. This was the first time that I flashed it so I assume it would have been whatever was on there when I got the car years ago. Anyway I can find out after the fact? In project properties, show advanced has options for: 029q, 029y3, 024s, and another 029y3.
After I updated it, I was able to run it for at least a day or two, does it still seem like that firmware could be an issue?

Also see on the 'read me' for 029y4:

"
029y4 uses different code for 3bar and 4bar sensors. It fixes an older
bug that caused the maps to run really rich compared to a 2.5bar sensor.
However, if you successfully used an older 029 series code you MUST add a bunch
of fuel to your VE table (maybe 25%) or you will run horribly lean.

If you ran 029b-029q YOU MUST RETUNE YOUR VE TABLE. If upgrading from
earlier codes or using custom sensors and Easytherm you should be just
fine.
"

I was running lean but I just assumed it was because I wasn't burning it all from having a weak spark. I wasn't 25% lean, but misfiring at least. 2.5 bar sensor.


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## fakename (Apr 5, 2012)

Reflashed, manually inputed constants, and imported tables. Got spark relatively consistently when I wired a plug directly to the coil but didn't see any spark running it through the cap and rotor. Battery was essentially dead though so I've got it on the charger now. I'll see how well it'll crank over in the morning, might be about time for another battery too.


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## fakename (Apr 5, 2012)

Battery charged and I get at least 10v during cranking so I think I'm good there. But same results as yesterday, I can get a spark rarely enough to know that something is working but so infrequently that it's essentially non existent, and weak when it is.

Spark output and irq trigger leds light up when cranking but spark output is noticeably dimmer than irq led. Does that imply anything to you guys? Going to unsolder, clean, and reinstall bip. Saw this and although I don't have a f***ing clue what dude is saying, I kinda want to test mine that way too


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## fakename (Apr 5, 2012)

Well I didn't do much other than unsolder and reinstall the bip, maybe cleaned around it a bit, but it fired right up. Actually accidentally ground my tach in wire while I was holding a plug wire and it shocked the S*** out of me! Not the first time that's happened but this one was a doosey... I knew that was a good sign. Car fired right up and ran really smoothly. Took a datalog with no resets, didn't feel any misses, increased my ve table by about 15% which will be fine for the time being out of boost.

I tested every possible continuous path from all pins on the bip373 and nothing was shorted or gave me any reason to think there was a bad connection anywhere. Just goes to show...

This started as losing my hall trigger, would a bad solder on the bip have had any effect on that?


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## ps2375 (Aug 13, 2003)

fakename said:


> This started as losing my hall trigger, would a bad solder on the bip have had any effect on that?


The BIP is what controls the coil.


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## fakename (Apr 5, 2012)

Yeah, but the ms needs my trigger signal before the bip grounds my coil, right? Doesn't seem like a bad solder on the bip would have any effect on my hall signal, so I still don't know exactly why ms wasn't getting my trigger initially.


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## ps2375 (Aug 13, 2003)

Well, if you had a short causing low voltage, that could have been effecting power to the hall sender and thus your trigger signal, just another theory..


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## fakename (Apr 5, 2012)

I'm hoping something like that is the case so that it's fixed.

Driven it a few times and I'm feeling good about having resolved my issues. Using ve analyse live for the first time, it's pretty sweet. Haven't had any misses and I think I'm getting a stronger spark than I've had in a long time, going to increase my gap!

Thanks guys for all the help, won't be the last time. :beer:


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