question for anyone that can help. I just got a 1985 iroc with 305 and TPI. When I first got it the left side exhaust manifold was getting hot!!!. So I got the heads redone and replaced all gaskets on the top end. Got it back together yesterday fired it up and the manifold is still getting hot. I don't know where to go from here. any help would be appreciated.

 

I'm not sure of your definition of "hot", but since exhaust gases going thru it are 1000+ degrees Fahrenheit, those manifolds are going to get really hot. Temps in the 750 degree range are not uncommon and the longer the engine runs (especially at idle) the closer to the temperature of their contents (1000* F) those manifolds are going to get.

Does this make any sense? They should not be getting hot enough to glow red though. If they're glowing read you either have a timing problem or the fuel mixture is way too lean or way too rich. If they're red, start out by checking your timing.

Hope this helps, if not let us know and we'll try again. Have a Great Day!!!


- Vern

 

It is not getting red hot but after about 30 seconds of running the left side is so hot you cannot touch it but the right side you can touch it is not hot. We checked the timeing and to get the timing right with a light it will not run.

 

Make sure you disconnect the EST connector over by the passenger's strut tower before you try to set the timing. Try it about 6* BTDC (at least that's right for the 90-92 305 and 350 TPI's......

Does it feel like it's missing out? That right side manifold should be getting hot too......

 

The EST is disconnected. It does seem to be missing out. But I can't tell which side.

 

You'll probably have to fix the miss before you can get it to idle smooth and be able to set the timing. Have you tried pulling plug wires or checking any plugs to see if they're firing? I had a miss and the only way I found it was to pull plugs. I had one totally clean plug, meaning it wasn't firing at all.

 

Sounds to me like the right bank injectors aren't working; probably because one of the "ECM" fuses is bad....

There are 2 of them in your fuse box. They are not for the ECM, they are for the injectors. TPI is a "batch fire" system, that fires the injectors in groups. Each bank fires all 4 injectors together. The 2 fuses are one for the right bank, and one for the left bank. Sounds like the right bank one is blown. Or possibly, the ECM's driver for that side is defective.

 

I wondered about that too, but since he said he just thought it might be missing out I figured surely it couldn't just be running on four cylinders. I would have thought that would have been a lot more noticeable (plus the total lack of power - 4 cylinders should have a hard time even getting up to 60 MPH.....)