# MS-Pro can't rev out cleanly... breaks up at ~4k... also hot restart issues?



## leebro61 (Nov 7, 2001)

EDIT - Rev issue resolved! Hot restart issue TBD.

So, I've had MS-Pro in my Corrado VR6 for ~700 miles now and I'm still working through some crank signal issues. Previously I had been running a used VR sensor and I was having issues with the car hitting a rev limit at ~4k, even after adding in a 10k ohm resistor. Recently I've replaced the VR sensor with a new oem unit and I've fixed my crank sensor wiring to be:

Pin 1: CKP+ with 10k ohm resistor
Pin 2: CKP-
Pin 3: Shield

With the addition of the new sensor the car builds boost, starts to stutter around ~4200 (feels like a misfire?), but if I stay in the throttle the car will pull through and starts pulling clean after ~5200 all the way to redline. A plot of one of the instances is shown below. You can see the white line in the top plot (RPM) is jittery in the circled region, then it smoothes out and the car continues to redline. AFR is bouncy too, but I'm not sure if that is a cause or an effect? The breakup appears subtle in the plot because I've really zoomed in on the x-axis, but in the car it is quite pronounced. 



edit - it does this under load (boost) and under medium throttle (no boost).

I'm running GM LS/Truck coils at 4.0 ms nominal dwell, NGK BKR7E's gapped at 0.030" (same result at 0.035" gap), custom MSD plug wires that ohm out similarly to the oem LS truck wires. I've checked spark at various simulated engine speeds and it appears strong across the board (I realize this is subjective).


*Some questions...*

(1) My battery voltage vs. dwell curve is anchored to no correction at 14.0V, but the car while running is somewhere around 12.9-13.0V, putting me at an actual running dwell of ~4.6 ms. Should I re-anchor the curve to no correction at my actual running voltage (or just shift my nominal voltage down)? Should I key in the GM dwell table and run off that? I've heard some complaints that the LS coils can be a bit erratic beyond 4.5 ms... not sure if there is any truth to this or not?

(2) Noise filter... at one point when my crank sensor issues first arose, Paul added a noise filter to my tune. Do I just need a stronger noise filter? No filter?




Now, for the hot restart problem. After getting the car up to operating temperature and shutting it off the car will crank and crank and crank without catching. If I let the car cool down for a while it will fire up and catch immediately. I have tried some of the cranking/startup menu options to fix the issue without any success or perceived improvement.

This issue only came about AFTER I replaced the crank sensor and fixed the wiring (CKP+/CKP- swap). Previously, I accidentally had the resistor on CKP-, so despite the RPM limiter, the car would start on a dime every time. I logged a "cold crank" and a "hot crank" and comparing the logs nothing immediately jumps out at me, other than realizing how low the battery voltage dips and what that does to parameters with a voltage correction... although this effect both hot and cold cranks ~equally. 

Any suggestions here would be appreciated! The hot restart issue has become very annoying because it prevents me from driving the car places where I know I will have to restart it again shortly after driving it (example: lunch breaks at work).


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## sdezego (Apr 23, 2004)

I wish I could help more, but have not personally had to deal with any Sync issues. From my novice eyes, here are some comments and suggestions.

1.) Did you reset Timing and timing parameters after changing VR sensor and Resistor? Base timing and verifying at points in the RPM range, what TS states matches your Timing light (actual)
2.) You did not show timing, so it would be interesting to see what is going on during that period.

Misfires usually show as Lean spikes (since you have unburned Fuel and Oxy), but that may not be saying that Dwell is not wreaking havoc in that range. In my experience, that is an area of high load and when IGN problem will be evident. What is EGO Corr doing there?

3.) I see you are showing a Missed Sync (2 losses). This can't be good. Was that during cranking? It looks like the log is high in that whole frame, so I am having trouble deciphering what is going on with the sync loss. Again, I have never had to deal with that.

4.) Less is more. I usually use the least corrections possible until I have a well seasoned tune/setup and then want to refine things one at a time. Voltage correction will affect Inj PW most. I would set it static to more realistic value of the Voltage you see. Beware, that the Corrado Cubby Gauge can be off and fluctuate more due to the crappy wiring routes that are used. ...unless you are using readings from TS itself.

5.) I know nothing about the noise filter table, but it seems that it is set to attempt compensation most (other than cranking) in the area you are having issues. Also, what is that Noise Filter Delay setting? Is that in Millisec? Maybe that is preventing the filter from activating when you initially romp on the throttle. IDK, but I would try disabling that table if you are confident that the VR sensor was bad and/or the Resistor on the wrong polarity was causing issues. It is easy to enable disable (may requires a power cycle of MS)

6.) Verify with someone that knows (or from tooth logging) , if changing the resistor to the correct polarity could affect Rising/Falling Edge setting, etc.

7.) Hot Restart - This can be a host of things and I have dealt with plenty, but odd that it just showed up with the VR Sensor resistor change unless it is causing Sync issues during crank and is worse when hot??? I can only tell you that my car likes a lot more fuel in the ASE table after hot starts. Also make sure your VE bins during crank (leftmost Columns up to 100Kpa) are reasonable first. Have you tried a little throttle when this happens? a lot of throttle to perform a Flood Clear? Again, maybe issue from Noise filter table now that you have sensor correct? Big Compensation in table during crank.

This link (Along with the link in the first post) are very interesting, although not sure if they are truly relevant -> http://www.msextra.com/forums/viewtopic.php?f=101&t=43861 60 -2 is definitely a higher tooth count wheel


Finally, I would start a Post in the MS Forum as you will be reaching a lot more people with in-depth knowledge of potential Code issues, MS3 Pro or circuitry nuances. be sure to post your .msq when you ask for help


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## sdezego (Apr 23, 2004)

Also, forgot to ask. Are you currently running sequential Spark or just Wasted Spark for now on your individual LS Coils?


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## leebro61 (Nov 7, 2001)

Shawn, great questions...

I did NOT re-test my ignition timing after the VR swap and resistor. I dont "think" that I should have to since my initial Cyl 1 TDC tooth offset was basically dead on with the specs Paul had sent me. I think he had 77* and I ended up at 78*. If all else fails I will check this again.

I am running waste spark right now (haven't even hooked up cam sensor yet).

I currently have EGO correction off (or at least that is my intent, will double check). In the middle plot you can see my AFR (red) and AFR target (white) and while the AFR is a touch leaner, it's still within bounds I would say for ~6 psig.

The lost sync counts are ONLY from cranking. I've verified this in a handful of logs. I'm actually wondering if this is a factor in my hot restart issue, although the lost sync behavior doesn't seem any different between the hot and cold crank logs.

Yes, when I say I am at 13.0V with the car running that is via the TS log (3rd plot from top, green series).

Yes, I think that swapping the polarity of the crank wires SHOULD switch from rising edge/falling edge, however I've tried it both ways and it still seems like falling edge is the winner (although I was expecting it to flip?).

Here is my plan for things to test going forward regarding the break-up issue:

1) take a crank tooth log and double check (then check again) falling vs. rising edge
2) turn off the noise filter, then try again
3) drop the nominal dwell on the coils 0.5 ms, then try again
4) check timing again, adjust if necessary

I'll probably give you a call this week with a progress report :wave:


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## need_a_VR6 (May 19, 1999)

If it was a VR problem, I would *think* sync loss would be recorded. I agree that taking some high speed (tooth) logs of that area would verify that it's not an input issue. I agree after swapping +/- on the VR sensor I'd expect you'd need to change the trigger edge. 78deg should be the trigger angle on this wheel, period, but verify with a timing light. 

Dwell has me thinking a bit and I have gotten behavior like that when the coils are over-dwelled and they fire based on temp protection turning on. I would look at the actual dwell in the logs and see where it is in that area. The OE coils are good up to 6ms, but different aftermarket variants could be different. Even at 3ms dwell these coils are beasts, so it's worth trying. Additionally, your higher gap being better leads me to believe the coils are *very* charged and not the opposite problem. 

If you look at the AFR in the log it looks to spike lean a bit and changes in the fuel table wouldn't explain the behavior (look at gammave in this area to verify). It's likely misfires, and could be simple as a bad plug wire, etc.


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## Prof315 (Jan 5, 2009)

You may also want to try turning OFF the noise filtering. I had a VW 60-2 trigger set up that would break up around 4-5K and it WAS the noise filtering causing the problem.


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## leebro61 (Nov 7, 2001)

Prof315 said:


> You may also want to try turning OFF the noise filtering. I had a VW 60-2 trigger set up that would break up around 4-5K and it WAS the noise filtering causing the problem.


Thanks for all.the suggestions guys. I WAS able to fix it last night. Im on my phone now so i will have to chime in later and explain what happened. Doing a full, clean pull was a really great feeling!


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## leebro61 (Nov 7, 2001)

leebro61 said:


> Thanks for all.the suggestions guys. I WAS able to fix it last night. Im on my phone now so i will have to chime in later and explain what happened. Doing a full, clean pull was a really great feeling!


Okay, so for posterity, here is where I went wrong:

When I originally wired the car I had the + and - pins on the VR sensor swapped from how I have them currently. This wasn't an accident, the car genuinely ran better that way at the time (likely because I had other hardware/config issues). The car would cut out at ~3k rpm, which prompted me to install the resistor on the CKP+ wire. After the resistor addition I could drive the car, and after tuning part throttle I started getting into boost and that's when I noticed my 'rev limiter' hadn't been eliminated but instead had been bumped to ~5k rpm.

At this point, I bought a new OEM VR sensor, installed it, then found out with the new sensor that the standard VR pin config actually worked better, so I swapped the +/- pins on the sensor plug. At this point I tried rising edge and falling edge and for some reason falling edge still worked better (car would barely start on rising edge). 

I went out and drove the car, and noticed that while it would rev out to redline, it would break up in the mid range. My first thought was a hardware issue, so I ohm'd out my plug wires, tested spark on all cylinders, regapped all the plug down 0.005", then tried again. This time the car would break up under any throttle, so I pulled it home and parked it and scratched my head as to why a lower gap would make the car break up worse. I dug back in to it a week or so later and found out that some how one of the plugs died after I regapped/reinstalled. I put all new plugs in it and the light throttle miss cleared up, but the car would still break up in the mid range. At this point I swapped back to rising edge, and voila, the car runs great now!

I got so excited last night that I forgot to shut the car down to test out the hot restart, but I'm guessing that this is also now fixed since my relation between ignition edge and VR polarity are now back to where they used to be before the sensor swap.

I feel kind of silly having made the post for what turned out to be a simple fix, however I think I just got tripped up because when I was playing around with ignition capture the first time, I had a bad VR sensor, which pushed me to the wrong polarity. When I played around with ignition capture the next time I had lost a plug, so hardware issues kept me from getting the ignition edge nailed down. The other thing that bit me was working on the car for an hour or two here and there instead of just working on it continually until it was done (work and other projects have kept me busy recently). It seems like every time I dove in to the car I spent most of my time trying to figure out what I had done previously and what conclusions I had drawn last time around...

I still have a few lingering projects to tackle (PID idle control tuning, maybe using MS to control boost?, adding in the cam sensor...) but for now the car runs and drives great. I couldn't be happier, what a joy driving the car now compared to previously with the SDS system! :thumbup:


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## need_a_VR6 (May 19, 1999)

Little things can be big things! I think a tooth log would have shown a double missing behavior, but I'm not sure why the error wasn't logged. In any case, thanks for the update, it should help others work through troubleshooting in the future. :thumbup:


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## sdezego (Apr 23, 2004)

So glad you got things on the right track.

I have solved my worst problems by just explaining the issue to someone else. I usually ended up figuring it out by just talking it through. It is easy to get tunnel visioned especially when it seems like you are making progress, but sometimes it is best to stop and start at square one again with just the basics.. It is easy to see something as a stupid easy solution in hind sight. 

I would still *at least* question whether you need the Filter code and also make sure your dwell is still reasonable and not near limits. Less is more 

Before adding any new features (other than WB EGO Correction which would be my next step), I would refine your Tune, Idle ACC enrich, add boost, etc etc. Make sure you are 100%, then *slowly* add and refine features 1 by 1 and thoroughly test. Idle control should be near last on the list. Nothing worse than trying to correct idle oscillation with 1 poor VE bin in or nearby idle.

I still have not enabled my IAC/ISV (even with A/C) after about 6 years of running, LOL Mainly because I have found that I have minimal need for it  IDLE is solid using EGO Corr (on at idle too) just using basic algorithm (I got frustrated with PID here).

Here would be *my* list of ToDo's


Sanity Check entire Timing Table again First
Tune IDLE VE at temp with EGO *off* (my personal preference), quick drive and repeat check
Check AFR Target Table and Turn on EGO Corr with your wideband
Tune VE table (but save Bin Values in and around your idle region for later manual input!) Trust me on this one, as I have found that there is too much going on for autotune to do a good job at near idle (esp w/ big injectors). I have found that logs and VE analyze does do a good job even in idle regions though. ...maybe just me
Tweak WUE, ASE (warm up enrich, Afterstart Enrich) if needed (cold and Hot starts)
Add Boost Control
Add Idle Control if you feel it is needed
Add other luxury features like Fuel Decel Cut, etc
Look at Sequential Spark/Fuel
...configure MS features to make coffee in the morning 

Another useful feature you may want to add early on is hooking up your VSS signal to MS, so you can Log and use Speed related features.

:beer:


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## leebro61 (Nov 7, 2001)

sdezego said:


> Here would be *my* list of ToDo's
> 
> 
> Sanity Check entire Timing Table again First
> ...


Shawn... great advice as usual. So, I drove the corrado to work today and realized that I still have hot restart issues. Luckily I went through the drive through at dunkin donuts this morning, otherwise I might have showed up to work even later than normal :laugh:

Anyway, after work I played around with the ASE cranking pulse and priming pulse. I found that the curves stopped shy of my hot restart coolant temperature and I thought at the very least I should extend the curves out and up a bit to capture all scenarios. I wasn't exactly sure if/how MS would 'extrapolate' to "off the chart" temperatures, so I figured I would give this a shot. This actually helped a ton! I also bumped my cranking timing up from 10* to 14* (my idle timing), and that also seemed to help. All in all, I probably ran through ~10 successful hot restarts and the car 'caught' progressively faster each time. It was overcast (had just rained) when I was doing this, so the real test will be sitting out in the baking hot sun :wave:


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## leebro61 (Nov 7, 2001)

leebro61 said:


> ... so the real test will be sitting out in the baking hot sun :wave:


I drove the corrado to charlotte last saturday and the car ran great the entire time (~230 miles round trip). This included probably a dozen hot restarts in the sun, ~90+ F outside temps. The only thing that didnt go as planned was the sunburn on my forehead from driving with the sunroof open :laugh:


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## need_a_VR6 (May 19, 1999)

You're supposed to tilt on long distance drives. :laugh:


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## sdezego (Apr 23, 2004)

haha nice.


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