# VR6 12v Idle on MegaSquirt 2 v3.0



## acee_dub (Jun 12, 2008)

Hello, I have run into some free time this summer and will be spending some of it on my slow project.. Here is a video of the startup and idle of my VR6 (no throttle touched). 






Can anyone guide me through correcting this or point me in the right direction, thanks all.


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## weejunGL (Feb 2, 2005)

first off, how is your idle controlled?


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## acee_dub (Jun 12, 2008)

It is PWM Idle on OBD2 TB


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## wrbusa (Jun 13, 2007)

It seems like it's getting too much air (and/or timing), then going lean. Maybe it's going into a low kpa portion of the map, which might not be tuned yet--do the afr's fluctuate with the revving? Is the timing at idle higher than the mid rpm, low kpa portion? Is overrun fuel cutoff enabled? If so, turn if off until the tune is streetable.

Crank to run is definitely low at 1 second.. I use at last 10 seconds and my current tune is 15 seconds. You want the idle valve to stay somewhat steady so that the idle can stabilize when the engine first turns on.


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## acee_dub (Jun 12, 2008)

wrbusa said:


> It seems like it's getting too much air (and/or timing), then going lean. Maybe it's going into a low kpa portion of the map, which might not be tuned yet--do the afr's fluctuate with the revving? Is the timing at idle higher than the mid rpm, low kpa portion? Is overrun fuel cutoff enabled? If so, turn if off until the tune is streetable.
> 
> Crank to run is definitely low at 1 second.. I use at last 10 seconds and my current tune is 15 seconds. You want the idle valve to stay somewhat steady so that the idle can stabilize when the engine first turns on.


If I am on the throttle it is very steady and the AFR's are good, I ran autotune on tuner studio and it adjusted it to my specified AFR.
If I stay on the throttle and ease it down to as low as I can get it, everything is smooth until about 1800rpm then it just dies out as seen in the video.


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## wrbusa (Jun 13, 2007)

At 40kpa and 1000 rpm the VE is 58, but at 45kpa it jumps to 90! this is a problem  .. So your VE table is either delivering a ton of fuel 2000 rpm and below compared to the rest of the range, OR 2000rpm and higher is not getting nearly enough. Whichever is closest, use that as a starting point for a large block of cells near where you think it will idle, then let autotune fine tune it. When you're done, the table should be relatively smooth, and you will have to smooth some of it by hand. 

It sounds like you may be asking autotune to do more than it's capable of. For example, a rich misfire from that 58 to 90 transition I talked about above will cause a lean AFR to the o2 sensor, which autotune is unable to sort out (or even worse add more fuel!). I've found Autotune works well for cruising and high load, but not so well for idle, light load or overrun. Also, use very slow and deliberate throttle inputs when using autotune. You can't expect it to sort out transients yet. That's what AE is for. So when you have an idle block on your VE table (start with 8 to 10 cells with the same VE value) lock it so autotune won't try to change it on you.

Next, your highest VE should be at the upper right corner of the table, not the upper right. You'll need to fix that by hand, because autotune won't be able to hit those areas enough to figure it out for you. That section of the table is used to catch a stall, so you should bump the timing a little up there, and slightly lean the fuel compared to where it idles.

Third, on your spark map, the timing transitions very abruptly between 1700 and 1300rpm at low load. This is because your timing is really too high at 1700 and low load at this point of the tune. Take the block from 1700-3500rpm and 30-50kpa up to 2700 to 4000 rpm in order to allow the timing to ramp a little slower down from 2700rpm to idle rpm. Once you're out on the road and tuning for fuel economy, you can increase the timing here, but for now, it should be more conservative so you can figure out the correct fueling.

I'd recommend starting with the spark and VE tables in this thread: http://forums.vwvortex.com/showthread.php?3566558-Purchased Scale the VE table using Req_fuel until it's able to run. This will get you the basic shapes of the tables, and you can use autotune from there for fine tuning. Hang in there.. as you log some quality hours tuning, the light will come on.. I promise! :beer:


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## wrbusa (Jun 13, 2007)

Oh, also noticing that your AFR table goes above 100kpa and is generally too rich. Unless you're running boost, scale it back to top out at 100kpa. 12.7afr at 100kpa is okay. From 75 to 90 kpa, 13.2-13.4 is good. From 45 to 75, 14.3 to 14.7 (even slightly lean is ok.. see below), and from 45 and lower, you can go lean (16 to 17 is safe).

Maximum efficiency is slightly lean 15 to 16, so use this in the cruising range (2500 to 3500 rpm, 45 to 70 kpa).

Idle depends on what your engine likes, but most prefer slightly rich (13.5 to 14). It doesn't matter too much here, since you'll be hand tuning the idle VE, and the O2 adjustment shouldn't be enabled below 2000 rpm, generally speaking.


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## acee_dub (Jun 12, 2008)

Thanks man! I will try this out soon, the engine is at 8.5:1 CR, I am trying to get it idling NA before I throw the turbo parts on, I have an HX35 I want to run on it. For fuel I have a Walbro 255lph inline pump (to use with the factory in-tank pump) and Bosch 650cc


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## Prof315 (Jan 5, 2009)

Well I see a couple of things going on right off the bat that are going to be an issue. 

#1 What firmware version are you running? Looking at the screen shots it's old. Do yourself a huge favor and update to the current release V3.3.1 .

#2 Since you are using an OBD2 throttle body you need to wire up the built in idle motor backwards (power on Pin 2, control on pin 1) and run it Inverted. That or build the circuit in this thread http://www.msextra.com/forums/viewtopic.php?f=91&t=48515 and wire things up as described. If you use method 1, ( wire backwards and run inverted) you may find that drilling a small (1/8" or smaller) hole in the throttle blade will improve idle stability.


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## acee_dub (Jun 12, 2008)

I am using MS2Extra Serial324, but will upgrade now.

Tried again with the following tables and got the below result:










As it started I blipped the throttle a bit to get it going and did not touch for the rest of the video.






It goes into negative throttle position, is this normal?


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## wrbusa (Jun 13, 2007)

Yes negative tps isn't on it's own bad, but you'll want to recalibrate it eventually. 

It looks like your injector pw is going all the way to 0.. are you sure overrun fuel cut is turned off? Also make sure the rev limiter, AE, launch control and any other advanced feature is completely off for now. 

When you're this far away from the right settings, I think the best way to approach it is to start eliminating variables. Are you working with the engine at or near operating temperature? if not, keep it running with the throttle until it warms up. This eliminates warmup enrichments and idle valve warmup ramping. 

Next, I'd pinch off the idle valve inlet or otherwise disable the isv (not sure how this would be done on the obd2 TB) and start with the set screw letting in more air than needed. Then, I'd slowly close the throttle using the set screw, adjusting the fuel and spark timing in small increments down to where I want it to idle. This is how I've done it with the OBD1 throttle bodies and it seems successful. After that, I usually have a decent warm idle and I can add back the idle valve and idle advance one at a time.

I'd also try bumping up the idle timing a bit. You could try 15 to 20 degrees. This can help because the engine needs less air with more advanced timing (also your static CR is lower than stock and therefore should like more advance) and if it helps then you know that the amount of air getting in isn't adequate and you can work on correcting that. 

HTH :beer:


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## acee_dub (Jun 12, 2008)

All work is being done on a preheated engine (I throw on the factory ECU and let it run to operating temp)
After updating TunerStudio and MS firmware to the latest I now have two VE tables? 










I turned off fuel cut limiting in the rev limiter options:










As for the TB wiring, I have inverted it (opposite of this diagram).









Pin 1 is now FIDLE (Motronic T68 pin 23 = FIDLE)
Pin 2 is now 12VDC (Motronic T68 pin 53 = 12VDC)

Here is a video of it after the changes:






The Pulse Width no longer hits 0, It kept stalling out if I did not add throttle, so I tried to add some timing, but it still kept stalling out.










Now looking back maybe I should have done another test before inverting the TB wiring, after having disabled the fuel cut.


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## wrbusa (Jun 13, 2007)

I appears like you're stabbing at the throttle (just looking at the tps gauge), which is not going to be helpful for you at this point. Try slowly moving the throttle until you get it to a point where the rpms are steady. Then, turn on autotune while holding that rpm. After 20 seconds, back off the throttle and then hold that for 20 seconds while autotune works, then repeat again. If it begins to stall, only push the throttle slowly back to where it was happy. The reason is, is that until AE is tuned, a quick open will cause an immediate lean condition and a quick close will create a rich condition. You want to see steady afrs for autotune to properly do it's work.


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## Prof315 (Jan 5, 2009)

Did you also set idle valve operation to inverted in the Idle control settings? You need to so that more DC = higher idle. What you are doing by running the idle motor this way is going from the rest position ( same as no power to IAC) to fully closed. You will see negative TPS percentages this way but MS can deal with that. Try running the engine with no idle control at all.... will it idle? If so at what rpm....


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## acee_dub (Jun 12, 2008)

Set the Idle valve to inverted in settings, did not make much difference, however there are no longer negative TPS readings.

I tried running with Idle Control turned off, it would not idle, stalled out quicker than with the PWM Idle enabled. 

Auto tuned while keeping it running using steady throttle (around 3000rpm), the RPM kept fluctuating downward by about 1500, after a few seconds of autotune adjustments it steadied out. I lowered rpm with the throttle, still keeping it steady, once again it started waving and steadied out, so I went even lower, it started dipping low and almost stalling, I heard a popping sound from the front (maybe out the intake?) Autotune was adjusting the fuel map so I waited a bit to see if it would correct it but it happened again a few times so I shut it off. (Not sure what is causing that / how bad it is). Here is the adjusted map Autotune produced:










I think autotune could further steady it but not sure about those pops it produced.

Edit:

Went and messed around with it some more, I set the idle control to off and auto tuned with different AFR table, eventually lowered it to 1100 by slowly releasing throttle.. then let off entirely and it was idling on its own  saved that .msq, turned on idle control and it idled again.. Went inside for a bit and came back out, wouldn't idle on its own anymore. It is a whole lot more steady now in low rpm than it was before.. If I throw on an OBD1 TB right now it would probably be good to go, or just adjust the throttle cable enough for it to idle :laugh:


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## acee_dub (Jun 12, 2008)

Messing about with it some more, trying to get the TB to respond.. I could not get response at all.
I have a good signal going in, similar to the factory except that it is 200hz (factory ecu sends 500hz~) 
The max and min voltage is very close to what the factory ecu sends.

When plugged in the signal is gone  What can cause this..

I have set the idle valve to run with the engine off in Tuner Studio for testing purposes.


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## 1broknrado (Jul 6, 2005)

*FV-QR*

Don't have any input, glad you're slowly getting it sorted out by yourself! I don't think I would have even attempted to get this going right. Have a pro do the initial tune, then you can fine tune if/as necessary. 

Good luck, keep it up! Don't swap out the TB, fix the little gremlin!


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## acee_dub (Jun 12, 2008)

Suspect that the TIP122 on FIDLE circuit may be bad.


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## acee_dub (Jun 12, 2008)

The TIP122 was bad, I must have burnt it from all the re-soldering I was doing upon initial installation.
Ordered a new one off DigiKey, threw it on, and it is looking good. Next I will need to get it to do cold starts somehow..


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## skibby (Dec 11, 2018)

Hey,
i have any question and hope you can help. What is your final setup to your Idle Control Valve?

Frequenz = 500Hz?
PIN 1 to FIDLE
PIN 2 to 12V
Valve Mode Inverted or normal?

Thanks,
david


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