I fixed quit a few problems with my 86 IROC with a swapped out 350 and the 305 TPI setup with some extras (I'm fixing someone elses mistakes). When the engine is cold it starts right up, after a few seconds idles down to about 650 RPM, then I put it in drive and when i push on the gass it bogs down. It doesn't stall or back fire and I could drive it, but I'm not even throwing any codes. Then when I turn the car off and try to restart it, it won't fire until I let it sit for about 20 minutes to a 1/2 hour. I've changed the ignition module twice thinking the first one was bad and still the same problem. I checked the TPS and it's at .56 volts, and I've set the initial timing in drive at 650 RPM at 6 degrees advanced. The only problem is when I hook the EST back up and start the car, the computer advances the timing to 12 degrees advance and it runs pretty choppy. I've changed many many parts, and I think the timing advancing is my problem, but what causes it? Please help, I'm so close with finishing all of the fixes, this hopefully will be the last.

 

Come on you guys, atleast one of you had to have heard of this.

 

i got that same problem on my 86 305 tpi trans am i even put back the original chip now when my mechanic screwed around with the timing it was retard 4 degrees but the car was quick now my car runs 16.10 slow for a 86 305 tpi with 3.42 gears

 

Have you checked your fuel pressure? You might want to invest in, or borrow, a scanner so you can see what is going on.

 

I checked it last night, with the key in the on position without starting the car, it read consistently at 39 psi. I've heard these cars take 40 to 45 psi, is this still ok?

 

If I'm reading this right, you have a TPI from a 305 on a 350? The first thing that came to mind was that the 305 uses 19# injectors vs the 22# for a 350. Couple that with the low fuel pressure sounds like it may be the problem, it's running too lean. I'm sure someone could elaborate a little more.

 

I should have included this, but I'm not positive on this. According to the previous owner, he put Corvette injectors in it, which should be 22 lb./hr. I'm finally breaking down and taking it to my mechanic Friday because I don't even want to look at the car anymore let alone work on it. When and if I find out what the problem is, I'll be sure to repost it. Thanks for the reply though.

 

This sounds stupd but check your oil, if you have to much even by a half a quart it'll do this and the car shake and bog around 1500-2000 rpm...I had the same thing happen to me when my fiance wanted to suprise me by takin it to sears for an oil change...BIG SURPRISE!!!!! I only had to redue the oil and filter my self

 

That sucks, I checked the oil and it checked out ok, but thanks for the advice. Never take you car to Sears.

 

Well, I got a call from my mechanic today, he said it's either the cam or a broken valvespring . I'll either be buying parts from Summit or I'll be in the market for a new engine, depending on how much he'll charge to install a new cam. As I hear more I keep you posted.

 

Well guys, the cam is gone and the rocker studs are beginning to come out of the heads. So now I'm going to part out the car because I don't want to put out any more money. Thanks again for all of your help.

 

While I was tearing into the engine to get it out, I noticed an externally balanced damper, so I looked at the flex plate and noticed that was externally balanced too. So I tore into it more and noticed forged .100 in. domed pistons, by *** it's a 383!!! So now I'm going to throw a new cam and lifters in for $130 and the heads are going to the machine shop today to get screw in studs and have the valve springs checked for $80. I'll probably get a new EPROM burned for it, but it seemed to run pretty good without a custom chip. We'll see.

 

good call....good call...glad u decided to stay

 

great discovery!