Stalling when engine-braking to a stop (RESOLVED)

[EHmotorsports]

hes running NB in stock location and a separate WB down stream.

 

[4thStroke]

I've had this issue come and go.

I recently swapped back over to my ethanol map and made the needed changes to run my ID2000s and the issue went away. I have no idea what the issue was, but sometimes when you get away from the .25g/rev at idle midset, the cars drive better.

I know for the sake of calibration and showing the internet nitpickers, it looks good, but sometimes you just need to make the "incorrect" changes for them to run properly. I've seen maps that look like a 10 year old configured on big injectors before ECMLink would allow for the proper configuration, when everyone said you couldn't run 2000cc injectors. The car ran amazing, but the warriors online went ape sh*t and the tuner got unfairly blasted.

Try a higher coasting FC offset and see how it reacts.

 

[EfiniX]

I'm wondering if this whole thing is the excuse I should use to convert to speed density...

 

[4thStroke]

I'm on SD and the issue still comes and goes depending on the map I have loaded. Maybe with a new map, something will change and the issue will go away. It's worth a shot. Using the MAF adjustment to dial in the VE table wil help expedite things, its worth giving it a shot before you scrap the MAF altogether.

 

[EfiniX]

Quoting prove_it:
Quoting EfiniX:
I've actually done a good bit of work on the MAFComp already and it's operating right where I'd like it to at normal RPM's. I'll pay more attention to it at idle.

I'll have an update tonight for sure. I've got an hour drive after I finish work today, and I'm sure it will present me with a stall opportunity. Even if it doesn't die, I can see if the dip has improved with my clamp adjustments.



What's your idle air per rev? Are you close to the .25 mark?



So interestingly enough, I was checking my IdleAirPerRev on old WOT logs (at idle, of course). I decided to check after a typical drive and I found my ISC position was a touch high and my AFPR was a bit low.

ISC = 40-
AFPR = 0.21 gm/rev

I adjusted my BISS to get the ISC value up where it belonged, and I adjusted my MAFComp to get my AFPR up a bit.

Since doing that, I have had NO issues.

Before


After


At this point, I'm not willing to say it's solved, so I'll update this thread in a week or two. Anecdotal evidence so far is very positive, with no change to drivability and no stalls. The change the MAFComp is a bit extreme looking, but the behavior is much more like what you would expect a car to drive like.

I should also mention that as I was troubleshooting, I would undo changes that didn't work, such as upping the FC Coasting Offset (which is back to it's original value of 60).

Fingers crossed...

 

[EfiniX]

I'm willing to say I'm good to go. I came off the freeway on my way to a client today and stopped at the bottom of a hill that always causes my car grief. No problems whatsoever. It dropped like a rock to 1100 RPM's and sat there until I was at a complete stop, when it settled to 950 (where it belongs).

Woohoo!

 

[coyotes]

I know who's tuning my ride when the time comes /ubbthreads/images/graemlins/grin.gif

 

[EfiniX]

lol. Me?

/ubbthreads/images/graemlins/smile.gif

but seriously, you'll need a dyno tune to get peak performance numbers. Evan put a great base tune on my car, but even he told me to put it on a dyno before dialing the turbo above 18psi.

 

[AllanL]

so what it related to the idle air clamp?

good to know you got it sorted out...

 

[EfiniX]

I have the clamp set at 60 (idle set at 950), but adjustments to the clamp yielded no noticeable improvements. Adjusting the MAFComp to bring the AFPR inline seemed to do the trick.

 

[AllanL]

sorry, but what's AFPR? /ubbthreads/images/graemlins/dunno.gif

 

[EfiniX]

AirFlowPerRev

It's a value you can log with link. it should be right around 0.25gm/rev




I'm still playing with mine. Just brining it up from 0.21gm/rev to 0.23gm/rev made a vast improvement. I'm going to turn my idle down a bit today (it's at 950) and continue some adjustments so I'm pulling more vacuum while stopped.

 

[EfiniX]

And for Evan

 

[pdxgeek]

Quoting turbowop:
I had this issue with 503 and there is a long thread I started that explains all the issues and attempts to fix it. I got it somewhat better, but never totally fixed, then I sold the car. Super annoying. Just starts doing it one day out of the blue. Good luck.



Just an update on 503, enabling the idle air clamp fixed this. /ubbthreads/images/graemlins/cool.gif

 

[turbowop]

I tried that when I was dealing with the issue. No change. I had it mostly tuned out by the time I sold the car to Josh. I'm glad it's running better now though.

 

[pdxgeek]

I did completely re-tune 503 in attempt to pass DEQ here. It was running WAYYYY rich below 3k. That may have helped.

 

[GSTwithPSI]

Can someone school me up on the idle air clamp? I searched around, even on the link forums, and couldn't really find much.

 

[manikbastrd]

Seconded^^^

 

[turbowop]

The way I understand idle air clamp is that you force the ECU to use an open loop type map when under the parameters you choose, rather than allowing the ecu to use all the sensors as feedback to control idle. But only using parameters like when disengaging the clutch when coming to a stop or when using AC.

503 definitely wasn't rich below 3k when I had it. Fuel trims were all on the money. Either the tune changed somehow or Josh had somebody mess with it.