Hello, I am new to this forum. I have searched, unsuccessfully for help with a problem I am having. I am hopeing that one of you nice people will take time to give me some pointers. thanks in advance.

on a 1994 4.0l 6 cyl I replaced the cylinder heads. I followed all the instructions in Haynes manauls. torqued down in order to specs. all new gaskets. new bolts. heads were used so I had them shaved/resurfaced.
My problem is the truck will not fire. Without plugs it is smooth. With plugs it bucks. I have triple checked the plug wires to the plug block. It just seems 'out of time'
what else can i check ?

 

did you tighten down all the rocker arms with the cam on base circle? i cant remember if you adjust those like a 2.9 or not...make sure that you did that and also make sure you have the firing order correct

 

I am still reading...... the crankshaft timing sensor that plugs in on the bottom of the fly wheel -- is that a suspect ?

 

it plugs in at the front of the motor by the harmonic balancer...if it ran before and you didnt unplug it i wouldnt see why...if it cranks and has a kind of "binding up" to it like when a small block chevy is hot and the starter wont turn it. i would suspect a timing issue, the firing order needs to be checked. look for a chart with the cylinder numbering in your manual and the coil pack should have the correspronding numbers in the center of the coil pack for you to connect the wires to. also, make sure the cam cynchro is plugged in at the back of the motor

 

I feel like a bone head

IT WAS THE FIRING ORDER

like you said.

It's running now!!! I am quickly getting over my mistake!
I have an exhaust leak -- no biggie.

thanks

 

re-tighten the exhaust manifolds after the first heat cycle (when still warm) and loosen up the exhaust at the flanges and neutralize it on the ball sockets of the manifold (may have to take it loose at the spring bolt flange too) and try that