key3

Hi, just installed my new motor in my 94 Z28 and was having some firing issues. When I first try to start it, it would not fire at all. Checked everything and found out that the pigtail to my coil was broke. Now that I got it to fire, its only firing on five cylinders. Took all the plugs out and 1,3,5,7 and 2 is firing good but number 4 was not firing at all and 6 and 8 looked like it was firing but not to good. This is my first LT1 and so far everthing that has went wrong has already. My motor is a 355 with the LE1, 30lb svo injector, OVC plug wires, areomotive fuel pressure regulator. Another thing when I finally got it to fire, it back fired really bad. I believe that was from turning it over when is wasn't firing. My question is why is number 4 cylinder not firing at all? Also it was my first time doing the OVC plug wires could I have messed one up? It also seems that the injector don't fit all the way in the intake and fuel rails like it should?

thanks
Josh

Guest47904

Do you have a spark at number 4 that looks like 1,3,5,or 7? If not, swap a plug and wire from a good cylinder and check again. If still NG, pull the cap off the distributor.

If spark is ok, confirm the injectors operation. First check pressure is to spec. Then confirm injector pulses with a noid light. If both those check out, pull the fuel rail up so the nozzles are visible and confirm 4 is firing like 2 while someone cranks it over.

I caution the use of the noid light. Many have made a poor connection with the light only to mistakenly believe there was no pulse. For that reason, an inductive pickup noid light is best.

12SCNDZ

Josh, Are your wires "custom fit"? Might be something wrong there, if they are.

Frank
CPT

2000GTP

I would double check and make sure the plug wires have tight connections to both the opti end and the spark plug. And as noted above, if you didn't assemble the wires properly, that could be an issue as well. Either pull a wire and hold it to ground and see if it arcs or a safer way, test the continuity of the wire with a voltmeter.

key3

Yeah Frank they are the Taylor made OVC. I am going to use one of my old plug wires today to see if I got any spark. All I know is I think I bit off more than I can chew. How can I tell if all the cylinders are getting fuel to them?

thanks
Josh

2000GTP

Speedygonzales went over it pretty well in post #2.