Or none?

Background:
'85 4+3 68k. New ignition system & plugs. New fuel pump. No Codes. No smog pump (condition was present prior to removal as well.) Until recently, it was running hot due to previous owner letting radiator clog. Oil was @ 240 degrees on hiway @ 70mph. Coolant guage was not working until I found the bad connection while R&R the radiator.

Problem:
It doesn't like to start as easily when warm. When cold, it fires up like no one's business. When warm-ish, I get a puff of smoke (possibly oily).

Problem:
At warm idle, it surges some from ~540 to ~680 rpm. Some days are worse than others.

Tests:
No vac leaks @ booster, PCV or canister (under tb) lines.
Fuel pressure is as follows: (cold engine, psi)
37 - Primed
37 - Idle w/o Vac Line Attached
25 - Idle w/ Vac Line Attached
32 - Engine Off After 5 Mins
26 - @ 10 mins
18 - @ 40 mins
10 - @ 50 mins
No fuel present in FPR vac line.
Leaker?
How do I test for rich/lean conditions?
I will be installing an AFPR. What should I set it at for best results?

IAC test shows fine.
No TPS test done, yet. What should the values be and between which wires?

I'll be doing a header thru cat-back system over the winter, as well as plenum porting and under drive pulleys. I will take it out to be tuned for these mods.

Thoughts?

 

I would check the Idle Air Control.... to start with.

Do you have the Helm Manual? If so, follow that... it has debugging/troubleshooting guides for these problems.

 

I'd also ohm those injectors hot and cold...the symptoms you describe
as far as starting sounds like leaky injector(s).

 

How long does it take to start when warm?
Did you check fuel pressure when warm?

Suggestions above sound good. Pull the spark plugs and check there condition and report back.

 

I fought with this for a while, I had a number of things that tested bad on my system (also an '85).

I would suggest this first. It's cheap, and it rules out something thats incredibly hard to diagnose:
Replace the pulsator with a piece fuel injection line & two stainless steel clamps. I wish I had done that first when other forum members suggested it.

Otherwise, I agree with the others that you sound like you are describing leaking injectors.

TPS should be .54 V (within .075 + or -)

 

Hmmm... Vette N00b emerging...

What & where is the pulsator?

 

The pulsator is right above the fuel pump. It is there to quite fuel noise and vibration. Most of the time if it fails the fuel pressure will bleed of rather quickly.

It won't hurt to remove.

 

Don't mean to hijack the thread, but how easy is the pulsator to get to? looking at the service manual it is talking about removing the fuel tank to get to the pump.

 

The pulsator sits on top of the fuel pump, which is connected to the fuel sending unit, which pulls out via the filler neck.

That was a run on sentence.

C4's are great in that reguard. It's an in-tank electronic pump, that you can have out in 10 or 15 minutes.

 

Thanks!

 

So... The pulsator is not important? What issues will result if I remove/bypass it?