ignition problem

[trav87]

anyone have any ideas for my 87 chevy pick up? it's a 305 with a noticeable engine skip. changed plugs, wires, cap, rotor,and coil. good compression in all cylinders and good vacuum. think it's distributor related? I'm out of ideas. thanks

[homefree]

I had a 1989 305 that had broken valve springs and it ran kinda funny, do a comp check. The springs have a inner spring that was broken on mine. Good luck.

[trav87]

compression was good across all cylinders. changed distributor today and problem was still there. still puzzled......

[RacinRex]

Hey Trav, something you might want to check is if I am correct it should be throttle body injected. If it is, make sure you have a nice wide spray out of the injector or try running some injector cleaner through it. How many miles are on the engine?

[72 rs]

i say itsthe computer, that was my prob.

[RABarrett]

You might try checking the compression while the engine is running. Check all of the cylinders, one at a time. The running compression should be the same on all cylinders. These engines were prone to camshaft related issues and a running compression check will indicate an issue of cylinder filling. Ray

[ChevyBobby]

Originally Posted by RABarrett

You might try checking the compression while the engine is running. Check all of the cylinders, one at a time. The running compression should be the same on all cylinders. These engines were prone to camshaft related issues and a running compression check will indicate an issue of cylinder filling. Ray

Ray, How much diferance should there be between engine Running compression test and cranking comprssion test with all spark plugs out?

[ChevyBobby]

Originally Posted by 72 rs

i say itsthe computer, that was my prob.

Is it possible for the computer to not fire 1 or 2 cylinders?
It seeming cylinder #1 an #3 are not firing. I did a cpmretion test.
With all plugs out and cranging the engine. All cylinders are 175 psi.
With the engine running all clinders are 75.psi. Anyone know if this is normal?

Spark plugs in cylinder #1 and #3 are a black. All the others are normal graying white like they are firing.

[broughy84]

personally the first thing i would check is the throttle body gasket. Are the plugs fouled?