Since I got my car, it seems to have same this particular IDLE problem, just recenttly I resolved it : when I installed my DSMlink (1G) I've found the O2 wire cut (the white if I remember well) so the car was having BAD O2 reading and stall each time I took my feet of the gas when cluth. The DSMlink could have helped a lot too, but now the car idle fine (with 720cc...) at last !! Sorry for bad english, I hope it'll help.

hey man, i didn't read the whole post just what u put down for your problem, but i have the same set up. first you have to make sure that the main setup is correct to your car make. and then you set the base to your injector size. that will make your car run...fine. but everything after that is just fine tuning.

11scndtalon said:

hey man, i didn't read the whole post just what u put down for your problem, but i have the same set up. first you have to make sure that the main setup is correct to your car make. and then you set the base to your injector size. that will make your car run...fine. but everything after that is just fine tuning.

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Actually, I have the MAFT set right for my setup. I have an eprom that compensates for my injectors already. The MAFT is all zeroed out. I've actually done a little bit of the low fuel trim tuning, and it doesn't help keep the car from stalling. I've capped the intake manifold where the PCV used to be routed, and I've checked for leaks. Jeff couldn't really help with the ISC since I have a lightened flywheel. I'm probably going to put a stock flywheel back in soon. I'm just really curious as to why everyone else who has put a lightened flywheel in isn't experiencing the same problem I am. I'd hate to drop the tranny and swap out the flywheel only to find that it didn't stop the stalling.

in my opinion the safc can't compensate for the large injectors of that size

11scndtalon said:

in my opinion the safc can't compensate for the large injectors of that size

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He has a chipped eprom ECU, he is only using the S-AFC to dial it in precisely.

Is it me or does it seem like a few people who have replied to this thread did not read my original post? If you don't read the whole thread, you won't see all of the factors and the things I've already tried doing to correct the issue. Please read the thread before posting a suggestion or diagnosis. I'm not saying I don't appreciate the help and I'm not trying to be an ass, but if you really want to help, please read everything before replying. Otherwise, it doesn't really help very much.

my buddy had a fidanza flywheel and he was having stalling problems when coming to a stop. he swapped in an o.e.m wheel and it was perfect. id wait to see if jeff can fix it with code but if not, you have a relatively easy fix.

Any updates on the EPROM/stalling issues, Luda?

psychlow said:

Any updates on the EPROM/stalling issues, Luda?

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No updates - I haven't figured it out yet, and I don't really know where to look next. Jeff at DSMchips hasn't gotten back to me to let me know if he can figure out the ISC code, so I really don't know what to try next except swapping the stock flywheel back in. I'm really disappointed - I figured I'd have plenty of people who could tell me what's going on. It seems like nobody knows. And I know there are plenty of people running a similar setup as mine. If I could just get some people to give me a list of things to check/try, maybe I could compare notes with what I've already tried. With all of the experience on this site, I'm surprised that nobody has seen this before. Just my luck that I end up with this problem that nobody's seen before.

I've already checked:

ISC - I've tested the coils and unplugged it with the idle set. It doesn't seem to be malfunctioning.
Pressure Test - I couldn't find any leaks in the system.
Flywheel - I don't think it's the flywheel, as there are too many people running lightweight flywheels with built motors that don't have this problem.
BISS - I've adjusted it already.
Disconnected the IC pipe before the MAF to check for turbulence or bad readings - wasn't the problem.

There's really only a few things left I can think of:

EGR? Leaks or clogs?
MAF readings being thrown off because of the blow-through setup? I'm going to try disconnecting the IC pipe before the MAF and see if it still stalls. Maybe the pressurized system is causing some funky readings. I might try switching it to draw-through and see if it changes things. *** update - I just checked this, and it's not the problem.
And if all else fails and nobody can give me any more useful tips, I'll put the old flywheel back in.

It will probably only get fixed by a chip..

I talked to some people and 911's and many other cars when fitted with lighter flywheels only run right with a programming mod.. They say that with the stock ECU their cars do it too.

Have Jeff write a chip with an 1100 idle, and you should be fine. You're right though, the culprit most likely is the combination of the revs dropping quickly because of the FW and the different cam profile. As long as you're sure your throttle body shaft seals, power brake assist, or anything else like that doesn't have a good size leak...

Yeah raising the idle is a good suggestion. Also, how long have you had the car running for? It usually takes my car 20-30 mins to idle well after I reset the ECU, during that time the idle will drop when I put in the clutch or rev it at idle.

I'll ask the porsche doc... A raised idle will help but its a bandaid. The best fix is changing the decel algorithyms on the chip.

I had the same problem with my 2g after installing the lightened flywheel, MAFT/AFC combo. Would stall low idle for a couple of seconds. I had to raise the idle with the BISS screw to about 850rpms, and then set my BASE setting on my MAFT one click richer. This seemed to correct the lean condition created by letting off the throttle. My idle now settles about 750-780. Also my ST fuel trims still read low but it idles best this way.

I guess on the 911's they raise the idle rpm and adjust the math that controls fuel and timing on decelleration..

The BISS tweek sounds like a good option..

Even on my pathetic 90 cams i have the idle set to 1000rpm. I used to vent wrongly and when you'd let off boost while slowing to a stop it would stall at times if it was much lower. Now that i run the maft blow through I don't have that issue, but i still idle at 1000rpm just because i suppose. If you can't get a chip burned to meet your high idle needs I'd just adjust the biss and see if it at least lessens the issue.

I still believe that the 1g BOV is WAY too small for the 56 trim esp with the 2.3 induced spool point...

Surge when you let off of WOT and the BOV cant vent enough is'nt good for MR turbo.

MNGSX said:

I still believe that the 1g BOV is WAY too small for the 56 trim esp with the 2.3 induced spool point...

Surge when you let off of WOT and the BOV cant vent enough is'nt good for MR turbo.

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I've seen people run dual 1g's with a t in the vacuum hose, well more of a Y since it flows a little smoother. I run the hks ssqv and it gets rid of all the air I'll probably ever need it to.

Ludachris said:

Just my luck that I end up with this problem that nobody's seen before.

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Don't worry - I've had about 20 questions I've posted that no one has been able to help with more than part of the problem, if at all.

I can't believe that no one mentioned these two before, so I'm going to throw these in -

I know that you said you 'reset' the TPS. Have you actually looked at the data 'live' on a logger to make sure that the TPS reads near 100% at WOT and exactly 0% at closed throttle? Does it increase nice and linearly as you press the throttle? (You can test this with the car off - just run your logger with the key on engine off.)

Also, what about your throttle closed switch? Is that hooked up and funtioning? Is the ground to the throttle body installed and intact?

psychlow said:

Don't worry - I've had about 20 questions I've posted that no one has been able to help with more than part of the problem, if at all.

I can't believe that no one mentioned these two before, so I'm going to throw these in -

I know that you said you 'reset' the TPS. Have you actually looked at the data 'live' on a logger to make sure that the TPS reads near 100% at WOT and exactly 0% at closed throttle? Does it increase nice and linearly as you press the throttle? (You can test this with the car off - just run your logger with the key on engine off.)

Also, what about your throttle closed switch? Is that hooked up and funtioning? Is the ground to the throttle body installed and intact?

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So it's funny I didn't check this before - I thought I had. The logger is reading 12% at closed throttle and 100% at WOT. Well, it should be about 10% when it's closed I think - is 2% off that bad?

The closed switch appears to work okay.

No 2% isn't that bad... why is it supposed to read 10% closed? Mine read 0% closed, 98% open last time I check... or are 2Gs different?

98spydert said:

No 2% isn't that bad... why is it supposed to read 10% closed? Mine read 0% closed, 98% open last time I check... or are 2Gs different?

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Mine goes 0%-98% as well, being a 1992.

I do believe it is supposed to read 10% when it's closed. Mine was at 12% also. I adjusted it to 10%. The FSM tells you to ohm it to something I'm not to sure sure I wasn't in the mode to do that. Was a lot easier to just use the Logger.

I always thought 1gs ran ~10-100% and 2gs are 0-100.

The blow-thru setup is kinda finiky. The GM MAF sensor has to be turned the right way so it reads all the air coming in. Believe it or not, it can't rotate 360 degrees and function correctly. The lil arrow on the GM MAF sensor (which tells you which way the airflow is going) has to be at the top, not the side, or bottom..the top, that can cause idle problems as well.