Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Ok, test for spark.
You can make a test plug with a new spark plug and some wire, a mini hose clamp and an alligator clip. First open the spark plug gap to around 0.075" and strip both ends of a 16 gauge wire about 4 foot in length. Attach the mini hose clamp around the threads of the spark plug cause that is a ground and secure it with the mini hose clamp with the bare wire end in between to make a good connection. Next, take the other end of wire and secure to an alligator clip.
Now, you have a test plug. Remove any spark plug boot you want and insert your test plug onto the spark plug wire end you just pulled off and ground the alligator clip. Lay the spark plug in some shade somewhere under that hood and then crank the engine and look for spark. It should crackle with sound and should be blue but red is ok, orange is a little weak. If it can jump that 0.075" gap you should have no problem igniting an engine.
You can also use that to check coils on some vehicles.
Also, there is a red wire at the fuel pump relay. That is the test connector. if you hook a fused jumper wire there from the battery you should hear the fuel pump run.
Let me know what you are missing, fuel or spark or both.
The coil you can test with an ohmmeter. the voltage to the coil with a 12 volt test light.
For instructions on testing the coil, click here.
Actually there are 5 pins on the relay, the other must be the ground.
It should be under the hood most likely on the firewall on passenger side. Let me see if I can find out exactly where it is.
Actually its on the drivers side fender. Click here.
The test connector is C8 and the relay is 15.
there is a cluster of wires. there is a red screwed to the box assuming that is a ground. then another red wire but it is like a battery cable size wire then the cluster. if i have dash lights and no fruel pump dont i just have a bad fuel pump??
ok will check when I get home at work till noon my time which is 8
;45 now. the relay has 5 prongs. They are numbered 86, 85 30 and such. there is also a diagram on the top of it, with wiring diagram on it
Thanks I will check it out....
need help on a 1999 Chevy K3500 pickup with a 7.4 L