Ok My buddy is in a bind (hopefully nothing is binding)
2000 3.4 L motor
Task: Intake manifold gasket replacement.

Removed top of the motor upper intake and fuel rails, kept the pushrods in order sticking them through cardboard. Non adjustable valve train apparently, rockers tightened back down. Fuel rail o ring replaced.
Car is getting air, fuel and spark.
firing order is correct.
No security light.
No frozen pulleys in the serpintine system ( I already asked him all of these things lol)
The starter will only turn the flex plate about an inch with plugs in. New ones and old ones. Piston is not mashing plugs.
Motor does not turn over even with one plug in it.
When all plugs are removed from the motor, it turns freely. Put 1 plug in and it does not.
No check engine codes

Anyone have an idea of what he did to this thing? I'm stumped and admittedly pretty useless after 1990 with cars.

 

Does it lock up with ANY one plug installed, or one particular one? Offhand, I'd look at one of two problems. Either you have a large coolant leak that's causing one cylinder to hydrolock, The other option is an injector that's either stuck open or has a grounded return wire that is holding it open. Again, the excess fuel in the cylinder can also lead to hydrolocking. Does the oil smell like gas?

It's possible that either the intake manifold gasket isn't sealing properly, or else you may have inadvertently pinched an injector wire. The GM port injection systems have a common +12v feed to the injectors. The ground side is switched off and on by the computer. If you nick one of these return wires and ground it, the injector is held open anytime power is on. One way to check for this is to pull the fuel pump relay, depressurize the fuel rail, then crank the engine. If the engine now turns over with plugs in place, the problem is a stuck open injector. If it still doesn't turn over, it's probably coolant. Good luck.

 

he said any 1 plug anywhere and it won't do anything.
no injector wires damaged.

I finally got sick of talking on the phone and stopped by his house.... after a couple of weak starts, I
Jiggled the ignition, and it fired right up.


SEnding weak signals I guess.

 

It was definitely the ignition. If you stick the key in and turn it normally like you are going to start the car, it would only crank 1/4 turn and then disengage.
However if you stick the key in, turn it to forward accessories, yank back hard on the cylinder, while turning it the rest of the way to start, it will fire up 75% of the time.

Thank you much for the insight anyway Joe

 

The ign lock system sounds like it's going bad

I had to have mine replaced, it stops sending signals to the ign mod. Mine cut off on the thighway while I was going 60