fuel pump wiring diagrams (engine)

Hello,

Here is a guide to help you check the wiring and the engine/fuel pump wiring diagrams below.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

I need instructions on how to change the fuel pump wiring harness on my 1998 Jimmy.

If you mean the connection on the end that connects to the pump it is a simple cut and paste operation. Basically you will cut off the old connector, go up the wiring an inch or two from the original connection. Now slip some heat shrink tubing onto the old wires. Twist and solder the new wires to each of the old ones following the same wiring colors. Once they are all soldered together smear some liquid electrical tape on them. Then slide the heat shrink over the connections. Shrink it into a tight fir. Now apply some more liquid tape on the outside. You want those connections sealed so they don't cause problems.

I have replaced the fuel pump, wireing harness, and check the fuse and the relay under the hood. I even check the relay behinde the glove box. All system seems to be a go. Yet it's not running yet. Now the GMC dealer tells me about this ( gas-oil ) switch! But they will not tell me where it is. Can someone please tell me where to go look. One of the relays has power in, and 4-wires coming out: only 3-wires have fire. Could this relay be bad?

You got 2secs to check for power at the gray wire on the fuel pump connector-if its there and the fuel pump is till not pumping check the ground side and also look for a voltage drop on the gray wire- On this ,Now the GMC dealer tells me about this ( gas-oil ) switch! they are talking about the fuel pump/oil pressure sending unit-see below how its wired.

The fuel pump/oil pressure sending unit is located on the no.6 below-its on top rear of engine near the distributor.

About a year ago I had to replace my fuel pressure valve on the spider fuel injector harness. After that every once in a while the car would just stop. After waiting about 5-10 minutes it would start right up and run fine. never could figure out what the problem was. Now when driving the engine speed surges and also hesistates when i give it gas. I thought I would first change the fuel filter but after that I am not sure whether it might be the fuel pump but that is only about two years old, or if I need a need the whole new spyder assembly or if I have to replace the injectors. Please help your advice would be greatly appreciated.

Sorry for the late reply. I'd use a gage and check fuel pressure first. With spider system, 60--66 psi, key on engine off. Sometimes the fuel poppets need cleaning.

Just to add, when the problem occurs, have a helper crank it, while you visually check for spark at the plugs. You can use a known good spark plug or spark tester, keep in the glove-box for future issues.

I was changing my distributor cap and roater and my truck will not start. I want check the wire order on the distributor cap. What is the correct order

4.3L Engines Firing order: 1-6-5-4-3-2 Distributor rotation: clockwise

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