Car Starting Problems
GM and GMC

1991 gmc s15 turn over but will not start an we just but a new cap rotor an new egr valve on it an it will not start what would be the best thing to do?

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Wiki User
09/12/2011

Any time a vehicle will not start I always recommend that you go back to the basics. Many people assume that because there is a computer in the vehicle that whenever it won't start it's GOT to be something related to the computer. Actually, that's not right. Usually it's something basic, you just need to know how to work around the computer controls.If an engine has the 3 necessary components, Fuel, compression and ignition, it WILL run. Fuel must be delivered in the right amount, not too much or it will flood, compression must be at the proper level, typically somewhere around 100 PSI, and ignition spark must be hot enough and delivered in the right timing.First, did it run BEFORE you replaced the parts? If so, failing to run now is probably related to something that you did, most likely the cap or rotor. If it DID run before, check to make sure that the plug wires are connected right. Pull the sparkplug in the #1 cylinder, cover the sparkplug hole with your finger or thumb, then slowly turn the engine by hand until you start to feel compression build. Then continue to turn the engine by hand until you see the #1TDC mark line up on the dampener pulley. Now look at the rotor. It should be pointed directly at the #1 plug connection on the distributor. If not, you've found the problem.Post on my message board if you'd like to discuss this further.