EfiniX
(Member ++)
06/26/14 02:40 AM
Stalling when engine-braking to a stop (RESOLVED)

Well I thought I had this sorted out, but it's acting up again on a long road trip today....

When I'm coasting/engine-braking to a stop, as soon as I take my car out of gear, the RPM's drop very low. Sometimes it stalls. Sometimes it doesn't. Starts right back up when it dies.

New motor. New ISC. Clean and grounded throttle body. No leaks. Pretty much new and/or tested everything. I'm running DSMLink V3 and everything looks dialed in. even did the idle set procedure. ISC postion is right around -33 and when it's idling, it's solid.

One thing I have noticed is the the AvgAirVolPerRev spikes when it happens. Also, the A/F is remaining lean, only coming back up to stoic after (and if) the low idle recovers. I say remaining because as I'm engine-braking (in-gear/no throttle), the A/F goes completely lean as one would expect. It's almost like the A/F isn't catching up with the idle when I take the car out of gear.

I'm waiting for my registration to go through on the ECMTuning forums, but if anyone here has some suggestions, I'm all ears!

Thanks

engine-braking to a stop


losing my idle after pushing the clutch in



lancerglx
(Newbie)
06/26/14 06:41 AM
Re: Stalling when engine-braking to a stop

Hi mate.. .
I got exactly the same problem....stallls when shifting into neutral when its at normal running temp.Changed the maf becayse i was getting code 25 (barometric pressure sensor)and all was fine for a month and a half.Now im back where i started..i allso changed thee TB
isc and all tps ips etc.


prove_it
(my racist jokes aren't actually funny)
06/26/14 08:24 AM
Re: Stalling when engine-braking to a stop

Check and make sure your idle switch is set-up right. In Link you can simulate it. I'd start there.

EfiniX
(Member ++)
06/26/14 09:03 AM
Re: Stalling when engine-braking to a stop

Yeah, I'm already stimulating idle switch operation and the tps is calibrated both for position and voltage

prove_it
(my racist jokes aren't actually funny)
06/26/14 10:12 AM
Re: Stalling when engine-braking to a stop

Are you MAF or SD? Do you have any throttle body leaks? Clutch properly adjusted>? Wierd question I know, but I had a car once that would stall when coasting to a stop like yours. Turned out the clutch was dragging enough to bog the engine and it couldn't idle.

slugsgomoo
(god hates stupid people)
06/26/14 12:40 PM
Re: Stalling when engine-braking to a stop

lightweight clutch/flywheel assembly? I know my 1g had that problem with stock idle and the fidanza for a bit. I can't remember what I had to do to alleviate it though since it was 5-6 years ago. :/

EfiniX
(Member ++)
06/26/14 01:58 PM
Re: Stalling when engine-braking to a stop

Quoting prove_it:

Are you MAF or SD? Do you have any throttle body leaks? Clutch properly adjusted>? Wierd question I know, but I had a car once that would stall when coasting to a stop like yours. Turned out the clutch was dragging enough to bog the engine and it couldn't idle.




MAF. No TB leaks (all sealed up by EHMotorsports when I got a new motor/head). In fact, it was doing the same damn thing with the old motor

New clutch. Doesn't feel like drag since it happens whether it's in or not (i can pump the clutch to get into neutral and then let up immediately with the same behavior). Normal flywheel.

Weird, right?


coyotes
(Hipster VR4)
06/26/14 02:07 PM
Re: Stalling when engine-braking to a stop

Check for boost leaks?

prove_it
(my racist jokes aren't actually funny)
06/26/14 02:17 PM
Re: Stalling when engine-braking to a stop

Is your MAF draw-through or blow-through? BOV recirc or vented? Have you tried adjusting the coasting fuel offset and airflow smoothing?

turbowop
(Hard Snarker)
06/26/14 02:18 PM
Re: Stalling when engine-braking to a stop

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.

prove_it
(my racist jokes aren't actually funny)
06/26/14 02:38 PM
Re: Stalling when engine-braking to a stop

Yea, suppose I should add that I think all 4G63's do it to some degree. I think the ISC drivers and ISC itself don't have the speed needed to "catch" the falling RPM's. 715 does it, but it's an ACT flywheel and SD. Never stalls but in hot weather she'll drop fairly low but recover.

EHmotorsports
(Capt Fabbin Stabbin)
06/26/14 03:00 PM
Re: Stalling when engine-braking to a stop

I am starting to wonder if the resistance in the harness is increasing just enough to cause this after long hot droves.

prove_it
(my racist jokes aren't actually funny)
06/26/14 03:30 PM
Re: Stalling when engine-braking to a stop

Hmm, good thinking. There are multiple wires for the ISC. On the other hand, the harness doesn't seem like it's near any major heat sources. I'd say it's not over 200 degrees while driving, but maybe that's just enough. Good theory to test anyway.

Evan, would you agree that it seems like mostly all 4g's do this to a degree?


strokin4dr
(fighting them with a large needle)
06/26/14 03:55 PM
Re: Stalling when engine-braking to a stop

I've a few cars over the years that have had the annoying idle issues.

Every car was completely remedied by:
-installing a rebuilt (new seals) throttlebody
-installing a clean/known good ISC
-blocking off the FIAV and coolant lines to it
-confirming that base ignition timing was set correctly
-properly setting the tps with dsmlink
-dialing in the MAS properly with dsmlink until airflow/fuel trims/etc were all in line.
You would be surprised how far off a 1g/2g/3g/evo mas can be even with the "correct" base settings that are on the dsmlink wiki.

My current vr4 did this when I first got it all put together and running (even with a rebuilt t/b) so I went through these steps and it never happened again. I have the idle set @ 800rpm and it stays there when idling. While cruising, when I push the clutch to prepare to stop, it falls to about 1200 rpms and slowly decreases to 800 by the time I stop.
I do have a fidenza flywheel btw and never noticed any unusual issues with it.

I was using a 2g MAS when I originally set this car up and got it working correctly. I did switched to SD a while back, not because of drivability/idle issues but because I had everything needed just sitting here.
Good luck!
-Ryan


EfiniX
(Member ++)
06/26/14 03:56 PM
Re: Stalling when engine-braking to a stop

Quoting EHmotorsports:

I am starting to wonder if the resistance in the harness is increasing just enough to cause this after long hot droves.




Well it is certainly more pronounced when I've been driving for a while. Just fine when for short drives.

Interesting theory...


turbowop
(Hard Snarker)
06/26/14 04:35 PM
Re: Stalling when engine-braking to a stop

I disagree that all do this to a degree. 503 had this problem and wasn't very modified compared to 1051. Even with a light clutch assembly and on SD, 1051 has zero issues with stalling, even with the AC running.

MellowVR4
(5" too short)
06/26/14 05:13 PM
Re: Stalling when engine-braking to a stop

Is everything tight? like the hose from the valve cover to your intake? My car had this problem when the BOV wasn't recirc. Just a thought

prove_it
(my racist jokes aren't actually funny)
06/26/14 05:37 PM
Re: Stalling when engine-braking to a stop

^ with that being said, check the PCV valve and hose. You could have a leak in there, or a bad valve perhaps.

EfiniX
(Member ++)
06/26/14 06:00 PM
Re: Stalling when engine-braking to a stop

New PVC valve. tested for leaks after assembly by EHMotorsports. Persistent issue with the old motor (and it's many, many vac leaks) and the new motor (with it's no vac leaks).

BoV isn't recirculated. I even have a nice, shiny thread here about the dodge mod I just did.

This is all so strange...


belize1334
(well bread and nobly conceived)
06/26/14 06:07 PM
Re: Stalling when engine-braking to a stop

When coasting down but above about 10 mph the rpms should stay up at about 1200. There are three things that can prevent this. 1) Closed throttle switch. If it isn't registering then the rpms will drop down to regular idle speed. If you're simulating it then this shouldn't be an issue. 2) Air leak. Especially the brake booster, which has the potential to draw a massive leak from the IM. 3) VSS (vehicle speed sensor). This sits in the dash and sends pulses to the ECU. If it's broken or the wiring is shorted then the car acts as if it's sitting at rest so it doesn't keep the rpms up for you. Corollary symptoms - wipers won't change speed with speed-up of vehicle. Launch control will be stuck in stop mode if you have it set up that way. If ECMLink allows you to log vehicle speed I'd start there.

EfiniX
(Member ++)
06/26/14 07:40 PM
Re: Stalling when engine-braking to a stop

Yeah, it coasts just fine. I"ve never had it stall while rolling on open road. Only when coming to a stop, when it is below 10mph for sure.

AllanL
(Heal and Toe)
06/26/14 08:09 PM
Re: Stalling when engine-braking to a stop

not the dreaded idle stall?

not this? click

i do not have such on my car, so i just increasesd the zero/low load timing areas of the timing map.


EfiniX
(Member ++)
06/26/14 08:46 PM
Re: Stalling when engine-braking to a stop

Might be. My idle air clamp is enabled, but the values are higher then the recommended values on the ECM website. I'll make some tweaks and report back.




EHmotorsports
(Capt Fabbin Stabbin)
06/26/14 09:08 PM
Re: Stalling when engine-braking to a stop

only thing that hasn't been done is the Fiav. we can block it off and check it again.

prove_it
(my racist jokes aren't actually funny)
06/26/14 10:28 PM
Re: Stalling when engine-braking to a stop

I'd try that too. That could be why it's worse when the engine is hot.

MellowVR4
(5" too short)
06/27/14 11:36 AM
Re: Stalling when engine-braking to a stop

What maf are you using?

LIV4PSI
(dyslexic 1051 )
06/27/14 11:46 AM
Re: Stalling when engine-braking to a stop

Quoting EfiniX:

Quoting EHmotorsports:

I am starting to wonder if the resistance in the harness is increasing just enough to cause this after long hot droves.




Well it is certainly more pronounced when I've been driving for a while. Just fine when for short drives.

Interesting theory...




The ECU makes the engine idle much higher during cold idle to help get it warm. I bet that is why it is worse during long drives.

My Subaru has this problem, unfortunately I just learned to live with it


lancerglx
(Newbie)
06/27/14 12:28 PM
Re: Stalling when engine-braking to a stop

would it remedy the problem if a fiav/isc blockoff plate was used since you can keep the engine at a sightly higher rpm when idle without it going too high high when its cold.I have the same problem but its fine when cold hence the revs are slightly higher,,then when the revs drop and its at normal running temp it will stall when shifted into neutral.

mitsuturbo
(Banthony )
06/27/14 12:34 PM
Re: Stalling when engine-braking to a stop

Quoting EfiniX:

New PVC valve.

This is all so strange...




A PVC valve? That is strange indeed. You may want to install a PCV valve instead. PolyVinylChloride and 4g63's don't go well together. Positive Crankcase Ventilation valves are somewhat beneficial, however.

Quoting MellowVR4:

What maf are you using?




This was asked previously. OP didn't answer.


EfiniX
(Member ++)
06/27/14 01:29 PM
Re: Stalling when engine-braking to a stop

MAF is stock, I think. ECMLink is configured with a Base MAF Type of "2G MAF".

Here's a picture if it helps?


coyotes
(Hipster VR4)
06/27/14 01:31 PM
Re: Stalling when engine-braking to a stop

That is definitely not a stock MAF. Engine bay looks real nice dude.

MellowVR4
(5" too short)
06/27/14 01:31 PM
Re: Stalling when engine-braking to a stop

RECIRCULATE the BOV.

prove_it
(my racist jokes aren't actually funny)
06/27/14 01:53 PM
Re: Stalling when engine-braking to a stop

He has another thread discussing his issues with his recirc, and the resolution for it. It's set-up right.

Not a stock GVR4 MAF, but a 2G. Pull it off and check for the honey combs, no combs makes for much needed MAF comp.


EfiniX
(Member ++)
06/27/14 03:03 PM
Re: Stalling when engine-braking to a stop

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.


mitsuturbo
(Banthony )
06/27/14 03:10 PM
Re: Stalling when engine-braking to a stop

Quoting prove_it:

He has another thread discussing his issues with his recirc, and the resolution for it. It's set-up right.






VTA with a draw thru maf is not "set up right" regardless of any electronic compensation.


BTW, what is the Coasting FC offset set at?


prove_it
(my racist jokes aren't actually funny)
06/27/14 03:22 PM
Re: Stalling when engine-braking to a stop

I don't get where you think it's VTA. Pic from his BOV flutter thread:



prove_it
(my racist jokes aren't actually funny)
06/27/14 03:23 PM
Re: Stalling when engine-braking to a stop

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?


mitsuturbo
(Banthony )
06/27/14 03:37 PM
Re: Stalling when engine-braking to a stop

Aha. Of course that's the first thing we all suspect when someone claims their car is dying on decel. I didnt see any mention as to it having been recirculated.

Still, i wonder though. What is the Coasting FC offset at? I had to raise mine a bit, although i have a far different setup than this.


EfiniX
(Member ++)
06/27/14 04:24 PM
Re: Stalling when engine-braking to a stop

Idle at 950 w/ FC offset @60. AirflowPerRev @ idle is stable around .25, so that's looking ok.

I've got my fingers crossed that the clamp works out.


prove_it
(my racist jokes aren't actually funny)
06/27/14 04:33 PM
Re: Stalling when engine-braking to a stop

Me too. Are you using the factory o2 sensor location, or do you have a WB simulating NB downstream? I know I have my WB downstream simulating NB and there is a latency there for the ecu to adjust trims.

EHmotorsports
(Capt Fabbin Stabbin)
06/27/14 05:48 PM
Re: Stalling when engine-braking to a stop

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

4thStroke
(Spence knows tools)
06/27/14 06:18 PM
Re: Stalling when engine-braking to a stop

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 shit and the tuner got unfairly blasted.

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


EfiniX
(Member ++)
06/27/14 10:26 PM
Re: Stalling when engine-braking to a stop

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

4thStroke
(Spence knows tools)
06/27/14 10:40 PM
Re: Stalling when engine-braking to a stop

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
(Member ++)
06/29/14 09:07 PM
Re: Stalling when engine-braking to a stop

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
(Member ++)
06/30/14 03:31 PM
Re: Stalling when engine-braking to a stop

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
(Hipster VR4)
06/30/14 03:36 PM
Re: Stalling when engine-braking to a stop

I know who's tuning my ride when the time comes

EfiniX
(Member ++)
06/30/14 03:55 PM
Re: Stalling when engine-braking to a stop

lol. Me?



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
(Heal and Toe)
06/30/14 08:59 PM
Re: Stalling when engine-braking to a stop

so what it related to the idle air clamp?

good to know you got it sorted out...


EfiniX
(Member ++)
06/30/14 10:12 PM
Re: Stalling when engine-braking to a stop

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
(Heal and Toe)
07/01/14 09:53 AM
Re: Stalling when engine-braking to a stop

sorry, but what's AFPR?

EfiniX
(Member ++)
07/01/14 10:05 AM
Re: Stalling when engine-braking to a stop

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
(Member ++)
07/01/14 10:06 AM
Re: Stalling when engine-braking to a stop

And for Evan




pdxgeek
(Newbie)
09/03/14 09:48 AM
Re: Stalling when engine-braking to a stop

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.


turbowop
(Hard Snarker)
09/03/14 11:34 AM
Re: Stalling when engine-braking to a stop

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
(Newbie)
09/03/14 04:07 PM
Re: Stalling when engine-braking to a stop

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

GSTwithPSI
(A hole)
09/03/14 06:19 PM
Re: Stalling when engine-braking to a stop

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
(A Negro's Savior)
09/03/14 09:20 PM
Re: Stalling when engine-braking to a stop

Seconded^^^

turbowop
(Hard Snarker)
09/04/14 01:57 AM
Re: Stalling when engine-braking to a stop

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.



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