NefMoto

Trying to diagnose what's causing my car to occasionally stall when I'm cruising then press the clutch. The engine will sometimes catch itself after dipping below idle.

 It will also happen sometimes when I start from a stop and slip the clutch while feathering the gas, and push the clutch back in.

I'll post the logs when I get home and am around my computer. Car is CH box 1.8t BT, A-box MAF, EV14 1000cc injectors

EDIT: First log is a stall after cruise, and second log is when the engine catches itself.

logs attached to first post.

Are you using ligth flywheel ?

I'm running a 7.5lb flywheel and never had a stall out like he's explaining.

how old is your timing belt? This is definitely a symptom of a worn 1.8t timing belt.

Clutch masters 19 lb flywheel. Timing belt is like 10-15k miles old

seen this with vacuum leaks also out of curiosity whats your turbo inlet pipe look like

99% its not vacuum related as I replaced all the lines with silicone ones. Also worth pointing out, the MAFless version of this file does not have this problem.

TIP is a 3 in stainless turn down to the A-box MAF with an AEM dryflow on the end. Don't think it leaks as the fuel trims are 2.8% at idle and .8% partial.

wow one of my buddys has a gt28 in 2001 a4 018ch with a 3" stainless and tip and it


stalls same way only way it wont stall is maf is unplugged


i m wondering if the distance of the maf from the turbo makes a differnce

I had issues with am extra ligth flywheel, solved modifying torque reserve and some refinement in TUVB, TEMIN and FKKVS, but car has stroker 2.0 with 11:1 Cr E100, 1.000cc and GTX3071R.

Yes, it make a huge diference... put MAF away from turbo... other thing is BLow-Off valve that didn´t close quickly (stuck and close slowly)

MAF is about as far away from the turbo as possible. DV is stock recirculated into TIP right at turbo inlet.

If you have no mechanical issues, the logical asnwer is injectors and/or MAF calibration...

revise all maps related (TUVB, TEMIN, FKKVS, KRKTE, etc.)

Exactly what I was thinking. TVUB and krkte are fine I believe as fuel trims are within 3%. FKKVS is all 1s and TEMIN is .387.

I increased idle torque reserve to see if that helps. Flashing today

How did the problem manifest?

Tuning is not the solution to all problems.

What is the thought process behind increasing idle torque reserve?

What is the minimum injection time for those injectors?

What is te and ti when the car stalls?

What exactly did you guys do to idle torque reserve? screen shot? and why?

I built an exhaust manifold for my car and was running MAFless until I could get an intake setup on it. It had some problems with idling and stalling until I increased requested torque at idle in IRL. Then when I got my MAF in, the problem started. I believe it happened before the exhaust manifold as well, but I can't quite remember.

I realize tuning doesn't cause everything, but I'm confident I have no hardware problems. I increased torque reserve to hopefully hold the throttle plate open more when the revs drop, and also because of overspeed's comment.

I got the minimum injector time from the ev14 migration thread. I'll have to do some research as to what it is actually supposed to be.

ti is 1.5ms when I let off the throttle, and jumps up to 6.25ms I assume to try and prevent stalling. I did not log te_w, but I have added it to my log file and will try and take another log today.

I should also point out that if I let the car decelerate in gear to around 1500RPM and then push the clutch in, the car rarely stalls and comes down to idle nicely.

This is when it stalls?

Correct. See attached image from the log I took not 10 mins ago

You hit TEMIN from ~2.5 - 3.5 seconds and it appears to cause the stall.

The real question might be why te drops to 0.5ms, but raising TEMIN might fix it.

The log shows that te is .44 at 2.5s whereas TEMIN is .3787. What should the new TEMIN value be?

I was thinking your TEMIN was 1.5ms for some reason.

Try TEMIN at 0.75ms. This shouldn't cause hanging revs or any other problems and may keep you above the knee.

Try to get the minimum injection time from ID if you can.

Set TEMIN at .75, problem is still present. Also, goes into the 11's in AFR at low load cruising.

Maybe I am overlooking something hardware related? Is there a function responsible for catching the revs as they come down and slowly lowering them to idle speeds? Like, the revs will drop and then catch at ~1100RPM, and then drop slowly to idle. Do you understand what I mean?

Post graph?

Done. Log too.

Take a look at my last post too, I edited it.

You mean Dashpot ?   Don´t think it´s you problem or "solution"...

Add to log STFT and MAF values (Kg/s)

They are in the log I posted.

And I was just suggesting ideas about the dashpot. I was always curious of that function anyway.

ID says as small as the software will allow.

Any more ideas?

What have you done with your rear 02?

I read in the me7 system strategy PDF something about the rear 02 sensor effecting fueling coming off throttle or something like that so the cat stays healthy. so I guess if its still installed or something isn't coded out entirely/correctly and coming off throttle is mega rich it might cut fueling back and stall? IDK just an idea.

What fuel pump are you running ?

o2 is installed in the downpipe, all diagnosis turned off in PROKONAL and ESKONF only deletes SAI pump relay. I'll have to look into it, but I don't think it will be affecting anything.

Fuel pump is a Walbro 255.

Could a faulty clutch switch cause this behavior? I noticed the two times I've tried to use my NLS it did not activate as wrll

Check function by going to ENGINE, then MEASURING BLOCKS, the 060. When the clutch is out the 3rd bit (from the right) should be 0. push the clutch in, it should change to 1.

Block 066, but the clutch switch seems to be working properly.

No idea where to go from here.

Another thing I noticed today, it only happens when the motor is warm.

I would bring the torque reserve back closer to stock. just guessing here though.

minimum engine load is less when the engine is warm so maybe you did too much of what you did but not for when the engine is cold. Also the issue is at a time when load is at a minimum but at a higher rpm. you let out the clutch and the engine drops rpm =  no/min load condition and then stall. maybe torque reserve doesn't have enough "reserve" for that condition.

After increasing it and it didnt help, I put it back to stock.

well damn..I have no idea.

you said that it doesn't do this with the MAF unplugged, have you tried using the ori sensor in a comparable sized housing to the one that's in there? I don't know what an A box gets for a MAF nor the CH box. I know some ECUs come with Hitachi and others Bosch and changes are needed to swap them. Also there are both narrow and wide band MAF sensors. Could it be that the maf in now is either a narrow or wideband MAF and the software is set up for the opposite? an example would be using a sensor from an AWW1.8t on an AWP 1.8t, narrow band sensor on wide band software.

I don't see how that could cause an issue. I took the MAF housing+bosch sensor from a 2.7t a6 and copied the MLHFM from the Abox and pasted into my file. Many people have done this without issue. I don't think it is necessarily the MAF because idle is rock solid other than this problem.

Does anybody know the actually name of the function, or "dashpot" as overspeed states, that catches the revs when coming down to idle? When I let the car decelerate to below 2k RPM and then push the clutch in, 9 times out of 10 the revs will catch nicely and descend to idle speeds. I may be chasing a red herring here but I'm always open to learning new me7 stuff anyway. And since everyone has run out of ideas it seems I am on my own for this one.

KIFZGHG?  "Integrator gain of the vehicle model for manual transmission"

Still haven't made any progress on fixing this. Anybody got any other ideas about this?

Could DV placement cause this? I moved mine to near the throttle body as opposed to the stock location right at the outlet of the turbo. Idk, grasping at straws here lol.

I have the Forge DV relocation kit with Forge DV installed on my car and never had that issue.

I just reread the thread to kinda update myself and I saw you changed MLHFM for the MAF and that seems to be it. Try changing KFKHFM to what it is from the file of which uses the MAF you currently have installed as it's stock unit or maybe "all 1 it". I think this will help out. I switched from the 1.8tAWP MAF(stock) to a 1.8t BEA which is a 3inch MAF housing with the exact same sensor part number as the AWP sensor. At first I only switched out MLHFM and was getting wierd dips in rpm at idle/offidle but it never stalled like you explained but would stall a couple times during a cold start attempt.( I am in FL so my idea of a cold start is like 72F) Also AFR would fluctuate constantly, I saw this from watching my WB meter match front o2 sensor lambda all while the engine rpm would surge and dip at idle. Sometimes if I really got on it during a run, afr would stay at like 10 at idle after and never re-adapt until I shut it off and restarted it and sometimes I would have to reset adaption values, after a few minutes a good AFR would be adapted to. If I was cruising before resetting adaption values, AFR would go back to stoich. I changed KFKHFM to the stock map values from a 1.8t BEA AudiTT225q, I think a CHbox ECU. Like magic, it all went away. I'm running just over half the injector you are and k04-023 turbo though.

KFKHFM is currently all 1's, and my intake tract is vastly different from an A-box car. General consensus seems to be resetting KFKHFM and tuning it via STFTs.

Couple of things I would check (I've been working to understand these functions myself since I hate how long it takes revs to drop on the 1-2 shift and may try to reduce the time a bit.)

Have you been through BBSAWE/fuel cutoff?  Could be a place to start/continue.  From this thread:  http://nefariousmotorsports.com/forum/index.php?topic=1710.15 Reply 19/Setzi the IDC sets whether the injector fires or not after injector on-time is calculated.  So even though you are showing that there is no fuel cut off, there still could be shutoff going on for some reason.  As an easy check, maybe increase KFTVSA, delay fuel cutoff on gear change (detected by the clutch switch, b_KUPPL).

Maybe you have changed things up enough mechanically that the idle PID should be looked at.  The Alfa FR page 570 (LLRM) describes the PID and how to go about tuning it.  Easy enough to put back to stock if it doesn't fix the issue...

(As an aside, somewhere in this thread someone mentioned torque reserve in the context of opening the throttle.  Torque reserve alters timing, not throttle position.  Increasing reserve pulls timing compared to base so that higher torque (from increasing the timing) is immediately available to react to loads.  Much faster than opening the throttle.  On the one hand, lighter flywheel = less inertia to carry through a starting load (A/C engaging for example).  On the other, it's easier to accelerate the load with a lighter flywheel -- so maybe less torque reserve is needed, not more?)

Thanks, I'll look into those modules and see what I can find.

As for idle reserve, it was my understanding that increasing idle reserve retards timing and opens the throttle plate at the same time. But I could be wrong.

I was thinking it wouldn't be just the starting load but the constant load after the accessory has been engaged.  like while the A/C is running, alternator load, PS pump, etc, or while all of it is happening. So a spike and then constant load. The ECU, I'm thinking would be using up more of the available timing with the lighter flywheel compared to a stock unit installed, If there were no changes made to the software. Does that seem correct?

I haven't found a thread in here yet that really goes in depth about what to change in the software for light flywheels or switching from a dual mass to single mass.  I'm thinking idle fueling would be needing some refinement because it should take less fuel to keep the lighter flywheel turning right? or will it take more because the lack of inertia compared to the stock flywheel?

Who wants to start a light flywheel thread?

1. More torque reserve is needed with lighter flywheels.
2. More proportional term is often needed as well.

Could this be causing my stalling issues? What is the general increase needed?

EDIT: I don't seem to have any of the idle PID components in my map pack, so I have been trying to locate them with a fully defined TT file. Not sure they are the correct locations. Don't mind the axes, I haven't looked into them yet.

any update on this

pooched injector seals.  ::) barely ever stalls now, dips below idle often though.

Hello guys,

Very interesting thread. May I add:

My car have similar problems. It dips RPMs on upshifts, when you are engine braking @2000-4000RPM and suddenly clutches in, the engine almost stalls.

The catch, I run E100 and have wall wetting issues that I'm trying to fix via KFBAKL, KFVAKL and other settings (still did not try to chance injection timing).

I do believe this is a problem with the Air mixture with the fuel when the Throttle closes a bit.

Did you discover anything other than injector orings?