Chevrolet Repair: Running Problem, oil pressure switch, fuel pump relay

Question
I have a 1993 Chevy Blazer S-10 Tahoe with a 4.3 Vortec engine.It has the high output CPI system.A few months ago I was driving home from work and it stopped running.It would turn over but would not start.I found that it was not getting any fuel to the engine.I replaced the fuel pump relay and it ran for about 2 months then it died on me again.This time I replaced the fuel pump and it ran for about 2-3 months and then I took it to the store and it was running fine but when I came out it would not start.I got it home and ran a wire from the battery to the fuel pump and it came on but still it would not start and it smelled like no fuel was getting to the engine.So I put some gas in the manifold and it cranked up and started running again.I was told it might be the pick-up coil on the distributor.I also should tell you that at no time did the Service Engine light come on.I did check for any Error Codes each time it happened and it had none.I would greatly appreciate any information you can give me to help solve this problem.My truck is in excellent shape.I have taken good care of her and this is the first problem I have had that has not been easy to fix.I have replaced the alternator once and the EGR valve and that is the only problems I have had with her.She has 151,000 miles on her.I look forward to hearing from you.

Answer
If the PICKUP COIL was at fault you would NOT have any ignition to the spark plugs. It has nothing in common with the fuel circuit.

If you want to test the pickup coil at the time that the fault occurs, I can provide you with the test sequence.

Here is HOW your fuel pump circuit operates:

As soon as you turn ON the ignition switch to start the engine a 2 second battery voltage signal is sent from the computer to the fuel pump relay and from the relay back to the fuel pump in the fuel tank.

Once the engine starts, The computer BYPASSES the fuel pump relay and now sends a constant contionous battery voltage from the computer to the oil pressure switch of which is now CLOSED because the oil pressure is UP because the engine is running. Therefore the battery voltage flows thru the oil pressure switch back to the fuel pump to run the fuel pump constantly until you turn OFF the engine.


What I would be looking for is a corroded or loose electrical connection at the oil pressure switch or at any of the electrical connectors from the oil pressure switch back to the fuel tank.

There is also a SINGLE BLACK GROUND wire that comes off of the fuel tank wiring harness near the fuel tank and is GROUNDED to the vehicles frame. If any of these circuits are loose or corroded it will start to cause a VOLTAGE DROP to the fuel pump of which will shut down the fuel pump until the circuit COOLS OFF.


If you want the PICKUP COIL TEST PROCEDURE:

Contact me at:


onlineautohelp@msn.com


In order for me to provide you pictures and procedures to fix your problem.



NOTE: This website is NOT mine and I am only a VOLUNTEER helping answer BASIC simple questions to those in need and this website does not allow pictures to be sent and or received.

Please include all of the information, MAKE, YEAR, MODEL, Engine size, and all necessary other information that you previously provided as well as the information that I just gave you when you contact me.



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