Paxky99

Ok so I hope this question isn't to stupid. So when I am turning the engine over trying to start it and finally get a little bit of kicking over only two cylinders at the headers are getting warm. Cylinders 1 and 7 would this be normal? The left bank ( 2 through 8) are ice cold. Cylinder 1 being the warmest.

Injuneer

To have combustion you need spark, fuel, and compression. The spark is easiest to check, one cylinder at a time - pull wire, hold near block (not with bare hand), look for spark. If you have an old fashioned timing tight, hook that up to one plug at a time. The fuel is a bit tougher. First check the fuel pressure with a gauge. If pressure is OK, pull the rails up, injectors intact, put a jar under each injector and crank the engine briefly to see if fuel is flowing. (Best done cold engine, outside, fire extinguisher at hand). Compression - if you've got fuel and spark to every cylinder, time to test compression.

If you have spark and the injectors are firing, the optical cam position sensor in the Opti is OK. But the rotor screws can fall out and the timing of the spark is wrong, so no combustion on some cylinders. Or someone indexed the splined drive shaft from the cam sprocket to the Opti incorrectly. Someone might suggest a “jumped” timing chain, but I've never seen that happen on an LT1.

GaryDoug

I apologize up front for not following all the conversation. But I had the same problem with my Chevy 5.7L boat engine several months ago. It drove me crazy for a while. No codes. The cause was a bad IAC valve. I eventually tried pushing the throttle up manually. Once the engine was started for about a minute or more it ran perfectly, and all day long. I was embarrassed ;-)

Paxky99

Problem solved. After chasing all the ideas I read here ( thank you everyone that helped) I went and replaced the optispark and it runs great again. I did pull the old opti apart and had a lot of moisture I think the seal on the spline drive was bad I dried it out and sealed the cap and thread locked the rotor screws and it ran good but we had a big rain storm and it died again. Thanks again everyone.