08superwhite

Ok, i got my car tuned the other day. The last 2 days now i have been having a problem. If I let the car sit overnight and the engine is cold, for about the first 3-4 minutes or so I will get a stumble at more than about 1/2 throttle. Once the car hits the first mark on the temperature gauge then it stops. My other problem is with my idle. It won't do it everytime but pretty often. When I come to stop (not after boosting) the idle will surge back and forth between like 500 and 1200 rpms. Sometimes it will finally smooth out around 800rpms and other times it will just keep doing it unless I hit the gas and let it come back down. Is it possible that I fouled my plugs on the dyno by running too rich? I was thinking this might be the problem, but why would it run good the rest of the time?

Also if anyone can get me a screen shot of the Maf clamp table i would really appreciate it.

torqueTc

iTrader: (11)

my car is getting done up at www.jeimportperformance.com right now. FI/C tune w/ dyno time and my trd intake install also. Should have my car back monday, but I may add more parts while its down there. Ill let you know how everything goes. Your running the latest firmware from AEM I assume.

java09

that flux at idle happened with my car when i was stock.. it happens sometimes... when i would come to a stop it would do the same then level at around 800... i think some tCs just have it..

B_Real45

You can always check your plugs if you suspect them..

Bryan06tC

look for a vacuum leak bud..... are you running an atmospheric dump BOV?..... just remember, if you are running one, that this is a MAF car and any unmeterd air coming in or metered air going out will make this symptom happen......

NA_TC_817

i also have that idle problem but it doesnt happen all the time maybe every now and then usually when i come to a stop it would bounce between 500 and 1200 and then when i come to a complete it would sit at 800

08superwhite

i'm running the newest firmware. i know about the bov, that was why i specified it was happening when i wasn't boosting. I played with it a lil today. If I dump a ton of extra fuel at it at idle then it seems to be fine. but my afr is in the low 10s then. I thought of a vacuum leak, but i'm pretty sure everything is good, except me around the injectors. I'll get a can of carb cleaner and spray around everything to check. Any other ideas?

paul_dezod

I have seen this happen where the cold start enrichment maps are effected indirectly from the injector change and new tune. As a result the cold idle problem will occur. The only advice I can give is to live with it because you can only correct this issue with the piggyback if you richen up the entire tune. Otherwise, you can't.

The staggering idle is pretty common on modded tCs. I have even seen I/H/E equipped tCs do this sometimes as well. The turbo guys do this more often than most though. This is a byproduct of a few different VE changes including MAF pipe, tune etc.

paul_dezod

Also, what BOV are you running? I have seen this more with GReddy and TIAL than HKS

08superwhite

well, i think i discovered the problem to be the same as enjoithis. i got an obd2 scanner and i had a code for cranshaft sensor malfunction. I cleared the code and it ran perfect. i am going to redo my vacuum map by watching the fuel trims on the scanner and see if that code comes back again.

Kydog

Sounds like another good old 2008 tc issue. Had/have same problems.

08superwhite

here is another update. i rember reading in one of enjoithis's posts that he was getting 15 deg timing advance at idle and that he didn't think it was rignt. So i checked and sure enough I am also getting the 15 deg adv. So I pulled 15 deg out at idle. It seems to idle alot better now. It still stumbles a lil bit when i first come to a stop but it steadies out much quicker than before

SoFloTC

iTrader: (3)

i have similiar problems... i turn my car on and it goes to like 1.2k rpm then down to like 500 and keeps stumbling and wants to stall.. once it actually did stall.. then i rev it a little but right when i hit the gas it tries to stall out then revs up... idk whats causing this...

enjoithis

Wow idk where i was but i just read this thread...

You pulled 15 degrees at idle? My mechanic said most cars idle with 5-10 degrees advance at idle, try only pulling 5-10 see if that helps. I kinda wanna grab a stock tc and see what their spark is at idle just so i know.

08superwhite - have you ran my map? I think you are running bigger injectors than me but do the injector size calculator and see if it idles normally with my map. My car idles as good as new still. I have a new version of my map as well if youd like to try it, pm me your email address.

08superwhite

no, i'm not running your map. i finally have it idling the way i want it. i pulled 10deg timing insteat of 15 and set the target afr at 13.0. it now idles better than stock

enjoithis

Thats a little more rich than you need it. I have my target set at 14.7 (stock) try to get it to idle between 14.5 and 15

what range did you pull your timing on? 2-6 psia & 400-1000 rpms?