Does this seem like a tuning problem?
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 800
Likes: 3
From: Port Orange FL
Does this seem like a tuning problem?
I just put my 94 vert back together and have a slight bit of an idling problem.
I did an extensive home porting job, put in larger intake and exhaust valves, roller rockers, Impala head gaskets (came out 11.3 to 1), Hooker shorties, new opti, and a very mild Lingenfelter cam with the following specs. 213/219 duration, 462/471 lift, 112 centerline.
It runs great and is getting 2 mpg more than it did before I did the work! It is still pulling hard when it hits the rev limiter so I know I am going to have to raise that.
I plan on putting a tune on it but have not tuned an LT1 before so I am not certain the idling problem is a tuning issue. I was looking for some opinions on that. I did not think the camshaft would require a tune to idle since it is advertised as having 0 overlap but perhaps the larger ports and valves are confusing the issue?
When I first stop at a light or a stop sign it idles perfectly for a few seconds and then it starts to stumble. If you let it idle it continues to get worse and worse the longer it idles. It never stalls but it certainly sounds like it wants to. As soon as I touch the gas it pulls away perfectly. Does this sound like a tuning problem or should I look elsewhere? I dont hear or see anything that looks like a vacum leak.
Thanks,
Roy
I did an extensive home porting job, put in larger intake and exhaust valves, roller rockers, Impala head gaskets (came out 11.3 to 1), Hooker shorties, new opti, and a very mild Lingenfelter cam with the following specs. 213/219 duration, 462/471 lift, 112 centerline.
It runs great and is getting 2 mpg more than it did before I did the work! It is still pulling hard when it hits the rev limiter so I know I am going to have to raise that.
I plan on putting a tune on it but have not tuned an LT1 before so I am not certain the idling problem is a tuning issue. I was looking for some opinions on that. I did not think the camshaft would require a tune to idle since it is advertised as having 0 overlap but perhaps the larger ports and valves are confusing the issue?
When I first stop at a light or a stop sign it idles perfectly for a few seconds and then it starts to stumble. If you let it idle it continues to get worse and worse the longer it idles. It never stalls but it certainly sounds like it wants to. As soon as I touch the gas it pulls away perfectly. Does this sound like a tuning problem or should I look elsewhere? I dont hear or see anything that looks like a vacum leak.
Thanks,
Roy
Burning Brakes
Joined: Dec 2003
Posts: 770
Likes: 0
From: Madison Mississippi
Roy, all that INCREASED AIRFLOW has the computer dumping fuel to trim things back out. Definately get a tune. I have been there before with the same problems try www.PCMFORLESS.com and hook-up with Alvin Anderson for advice right here on the forum. You will be amazed how much better your car will run after the tune. Good luck 
Last edited by RUBYREDVETTECARD; Jan 28, 2006 at 08:45 PM.
