Originally posted under general engine tech. No response

87 Z28 LB9 Auto trans. Edelbrock catback, headers. No egr whatsoever, no air pump, no cat, Vortec heads, SDPC TPI baseplate, stock cam, LT1 24# injectors. Bi passed TPI coolant at air intake. adjutable fuel pressure reg. 58 psi

Problem run rich under throttle according to the AFR gage. Does not seem to be getting enough fuel at idle. Idles rough and rpm's flucuate between 1100 to 500. Often stalls when surging. Have to put it in neutral when I stop. Seems to idle better then.

I read somewhere "and of course can't find the article on putting vortec heads on a TPI 305" that TPI cars idle bad with vortec heads until the Chip is updated

Wanting opinions on if anyone thinks this will completely fix the problem or if something else might be wrong.

I have checked and fixed a couple of vaccuum leaks. There are not any more. I triple checked. No signs of head gasket leaking either although I have not done a compression check.

Questions.
1 Does anyone know who wrote that article (magazine) on putting Vortec heads on a TPI. It was very specific as to how much to mill off the heads for a 305 etc.
2 Has anyone else had this problem, What did you do to fix it.
3 Which company is the best for burning a chip for this application
4 Will a new chip fix it?

Anyhow please give your input

Thanks


__________________

 

Fuel pressure sounds pretty high, especially if you say it's running rich.

My car is basically stock, but I had a bad idle surge like you indicate with 500 to 1100 rpm lope and stalling. Turned out to be a bad injector so I just replaced them all with Bosch/Ford injectors and no more idle lope. Runs great.

 

I think it was march 99 car craft they built a vortec head 305 and made 325 HP.