4.9L trouble starting engine after rebuild
 

I have a 1992 seville
I recently stripped the engine down, replaced all gaskets and seals and put it back together but now im having trouble starting it.
when i try to start it, it turns over for a second, sputters, then stalls
if i move the timing up, it revs to 3500 rpm and stays there.. even with the butterfly valves closed... i can slowly push on the accelerator and it will redline but if i push it hard the revs die down and then it stalls....

after each attempt, i have to turn the key back and forth so it primes and then it will do the same thing if i try to start it again

any ideas?

are you getting any codes. If the CEL is on pull the codes and that should give you some ligt on the problem. I want to say it sounds like the IAC may be bad. try to clean it off and see if it helps. Or it could be the electronic TPS motor (little black box with small aluminum rod) wich is by the throttle body, could be stuck or needs adjusted.

Why was engine taken apart? Are all the ground wires attached, there are several attach at alternator bracket, and at least 1 at front head. Ground wires fasteners are not painted; should be silverish in color (DFI is very particular concerning grounds). Lastly distributor housing has cam sensor in it and needs to be oriented correctly in block so injector timing is in sync with valve timing.(intake valve is open when injector sprays fuel). Also post codes if present.

ya after i try to start it, that little black box on the throttle (TPS motor?) clicks for a while pushing the throttle a little bit over and over... what does that mean? and how do i see what the codes are?

and one of the head gaskets blew.. thats why i had to take it apart

Clicking has to do with TPS value. Idle Speed Control (ISC, little black box with screw that contacts throttle lever) extends to move throttle (TPS) to a certain reading computer wants at start up. PFI has "Learned idle" when battery or ECM is disconnected it can be erased all causing ISC to ratchet until it relearns itself. So it maybe normal. On-board Diagnostics and Idle learn should be in FAQ section.

Your 92 has brittle wires and connectors.
It does sound as though you may need a new ISC. Clicking and clacking are the symptoms.

But that would not necessarily cause the off revving and stalls.
I would take a close look at the connectors to and from the ISC. It is possible that one or more of the pins (or the wire itself) have been damaged.

I had a bad revving and stalling problem with my 93 after replacing the ISC. It turned out that one of the pins on the "far" end of the male connector was broken.

You may only need the cable/connector, not the whole ISC motor.