I have just rebuilt my motor, 350 -.40 over, 224 236- 114 cam TFS heads. This is a 94 lt1. Everything is great except I have a high idle that I can't figure out and it is pissing me off! This is a blower motor 9.5 -1. All I want to do is break it in for a few thousand miles and continue with my project. I have datamaster and have been mess ing with the IAC to no prevail. I have hhad the intake off 3 times and it is sealed up real tight now. New wires, plugs. I have had my IAC counts form 160 -15 and it doesnt do squat. I can not find a intake leak anywhere, I even listened around with a tube and nothing. Adjusted my rockers 3 times also so I know it can't be those.

I'm just at my wits end here......... but I came this far so this has to be overcome.



I can send some a log from datamaster but I cant see anything wrong with it, no codes or anything.

HELP!!!!

 

How high are we talking? I just started my 383 and it idles a LITTLE high... I think because the roller rockers aren't perfect yet. Mine is only idling about what it should, idle set at 875, idles just under 1000 on stock tach. I have been told also that stock tach reads about 100rpm high, is this true? anyone that can varify?

 

Who programmed it, and what is the target idle speed? Have you checked the TPS voltage to insure it is below 0.90V at closed throttle?

 

Idle is set at 900, tps voltage whan adjusting the TB screw has been from .47 to .82.

The idle goes form 1000 to 1200-1300 It is obvious that it is to high. but it runs more like 1200 consistantly.

The tune I have in there now is from a good friend of mine that had a similar set up, this was just so I could get the car running somewhat good, the previous tune was for a CC306 and mild stock heads.

 

I am geting the RPM from datamaster, plus the tach and DM are almost the same.

 

Well I cleaned my MAF and looked over a couple things, Started it up and got inside. There seems to be a vibration coming from somewhere. Definetly is RPM related.

Got the car off the jackstands and put it in gear(A4). There is definetly something wrong. When it is put under load it fells like a dead cylinder.

Is It possible to get no codes and have a opti failing?

I just dont get the high idle, which I still cant get to go down.

 

Sure... the only codes the Opti sets are for the optical sensor. There are no codes directly related to the high voltage (cap and rotor) section.

 

Well I think I am going to replace it. Since there is only 2 more things to replace to cover the whole ignition system. I will check back when this is upgraded. So there might not be anything wrong with the opti it self but the cap and rotor might be messed up, that is why it starts but doesn't throw any codes.

I'll replace the whole thing.

Thanks Injuneer, I will get back with you.

 

did the opti fix it? My car wont run right either and I am suspecting opti... 2000rpms and it drops cylinders, then picks them back up.

 

Yes, the opti did fix it! I just haven't got to drive it because it is raining. Maybe today after work.

When I removed my old opti and turned the pin it did sound like the bearing or something is grinding, I'll open it a little later and take a look.