Big Block ????

What is the cranking compression, and how much fuel pressure are you getting to the throttle body?

Sorry for all the questions

It just sounds like something is amiss, and I haven't been able to put a finger on it just yet.


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compression is pretty eaven across the board,and the fuel pressure is about 30 to 32 lbs.
Changing cam out tomarrow,I guess we'll find out if I'm right about it or not.

How about a vacuum leak around the intake that the guy bolted on? I would put a vacuum gauge on it. Also look for hoses that are disconnected or a gasket leaking around the base of the TBI.

The guy might have had the TBI sitting on the shelf for years. I would remove the injectors, verify they are clean and the correct Volume (lbs).

Unless that cam is super radical it should not have any affect on the TBI setup. Knock sensors work with from vibrations in the casting of the block, which is usually detonation but could be a rod knock, a crank with too much endplay or oil clearance, wrist pins that are stuck in the pistons, an oil pump with a chipped internal gear, a broken piston skirt, a busted windage tray (hitting the crank) or about a hundred other random things.

All I am saying is don't go tearing the motor apart just yet. There is a good chance you won't get it back together right and end up screwing something up that is big.

I would be willing to guess that it isn't the cam anyways...

TBI fuel pressure is usually around 8-13 PSI. Are you sure you do not have too much fuel pressure?

"eaven across the board" does not answer the question of "how much cranking compression do you have?"