idle stability

**383ls6** · 02-22-2013, 05:00 PM

I recently installed a stall. since then my car wont idle,especially when cold. TPS volts are at .55 throttle closed IAC counts around 120. the idle surges from 500 to 1200 rpms and dies. I can 2 foot it and keep it running most of the time but it continues to die. took it to a tuner last week ran fine for 1 day and started doing it again, going back monday. tried a IAC but that didnt fix it. was just curious if anyone else has ever had this problem and what the fix was.

**Knight** · 02-23-2013, 04:46 AM

Almost sounds like a vacuum leak. You might start by checking all the vacuum lines.

**383ls6** · 02-23-2013, 06:13 AM

no vacuum leaks. fuel trims -3% to +3%. :-(. everything was fine. disconnected battery for a week while i rebuilt trans and added stall then no idle and it has gotten worse over the week.

**cammed goat** · 02-25-2013, 08:26 PM

What exhaust are you running? I ask as I am wondering if an O2 might have been damaged while removing your Y-pipe to get to the trans. What did your tuner tell you after they did their work?

**cammed goat** · 02-25-2013, 08:28 PM

I can't remember if there is a vehicle speed sensor in the F-bodies.

**0rion** · 02-26-2013, 02:58 AM

Originally Posted by 383ls6

I recently installed a stall. since then my car wont idle,especially when cold. TPS volts are at .55 throttle closed IAC counts around 120. the idle surges from 500 to 1200 rpms and dies. I can 2 foot it and keep it running most of the time but it continues to die. took it to a tuner last week ran fine for 1 day and started doing it again, going back monday. tried a IAC but that didnt fix it. was just curious if anyone else has ever had this problem and what the fix was.

what other mods do you have and do you know what adjustments the tuner made? Where is car's idle supposed to be?

**383ls6** · 02-26-2013, 12:18 PM

car is at the tuner as we speak. they want to keep it for a few days so patiently waiting. fingers crossed. will post up when i get it back. thanks for all the replies.

**cammed goat** · 02-27-2013, 08:18 AM

Get back to us with what the tuner found.

**383ls6** · 02-27-2013, 05:28 PM

Originally Posted by cammed goat

What exhaust are you running? I ask as I am wondering if an O2 might have been damaged while removing your Y-pipe to get to the trans. What did your tuner tell you after they did their work?

kooks,catless with 4" mufflex

**383ls6** · 03-01-2013, 05:15 PM

still havent gotten my car back yet. they got it to idle while cold but when you drop it in gear it dies. they are saying my computer is not fast enough to keep the idle stable???? idled fine before. now im getting really concerned. bout ready to tell them to bump the idle to 800-900 rpms and see what happens.

**0rion** · 03-01-2013, 05:39 PM

Originally Posted by 383ls6

still havent gotten my car back yet. they got it to idle while cold but when you drop it in gear it dies. they are saying my computer is not fast enough to keep the idle stable???? idled fine before. now im getting really concerned. bout ready to tell them to bump the idle to 800-900 rpms and see what happens.

hopefully that's not exactly what they're saying because if it is I would take your car somewhere else. Did it just start doing it immediately after the stall? It doesn't really sound stall related to me.....it sounds like unmetered air to me such as a vacuum leak. 800-900 is too much on a non-cammed car. I have my cammed car set at 825-850. You might have to have the car idle at 700ish with the stall to help it keep from dying when putting it into gear but shouldn't need more than that. I'll try to look through my old tunes and see where I had my idle when I was stall only.....I want to say it was 700 but that's a guess.

**383ls6** · 03-01-2013, 06:41 PM

I have a fully built 383 in it. cam is .556/.556 lift 228/238 duration cam. 92/92 FAST intake. AFR 210 cc heads 10.7:1 CR. 440rwhp/420rwtq. when i got the car back the first time hooked my tech 2 up and it said the desired idle was 679 rpms which seems a bit low to me but my training is in OE repair. not so much aftermarket on the new stuff.

**0rion** · 03-01-2013, 06:59 PM

did it run fine then? That idle does seem a bit low. Is that cam on a 114? In that case I would have them go to 850 or so and see what happens....bet it idles much better. How much experience tuning do they have with cammed cars? Idle airflow tuning will fix a lot of idle issues but it has to be done correctly.

**383ls6** · 03-01-2013, 07:03 PM

its on 110 lsa. havent used these guys before but they come highly recommended and have some pretty nice cars in there. gm only. maybe its time for me to get hp tuners of efi live.

**0rion** · 03-01-2013, 07:52 PM

wow....what's the advertised duration numbers for that cam? I want to calculate the overlap. Can't get an accurate number using .50 numbers. The advertised numbers will be on your cam card.

**GTP231** · 03-01-2013, 07:56 PM

Did you try unplugging the maf and seeing if putting it into speed density helped? Sounds more lIke a vacuum leak or maybe the below came loose at the tb.

**383ls6** · 03-02-2013, 04:03 AM

Originally Posted by 0rion

wow....what's the advertised duration numbers for that cam? I want to calculate the overlap. Can't get an accurate number using .50 numbers. The advertised numbers will be on your cam card.

its an ASA cam with 1.8:1 rockers.sorry its 226/236 duration. didnt come with a card. probally couldve made a better cam choice. i miss the old days lol give me a carb and a distributor and we wouldnt be having this conversation.

**383ls6** · 03-02-2013, 04:05 AM

Originally Posted by GTP231

Did you try unplugging the maf and seeing if putting it into speed density helped? Sounds more lIke a vacuum leak or maybe the below came loose at the tb.

no didnt try that but iwill when i get my car back if im still having problems. dont think its a vacuum leak though as my fuel trims are ok

**cammed goat** · 03-03-2013, 05:02 PM

Well, if they know what they're doing, they'll correct the idle problem and advise you of any changes necessary for that engine.

**383ls6** · 03-04-2013, 01:07 PM

picking the car up tomorrow they said they set the idle around 1k rpms and that it will die if you do a cold start and immediately put it in gear. have to let it run for a couple of minutes and then its fine. Anyone know of a tuner in the dallas area? couldnt hurt to get a second opinion.