1993 Chevrolet Silverado • 155,581 miles

Hi, I have a 93 silverado truck with a 5.7 and was doing some trouble shooting. I unplugged my fuel pump relay while the truck was running and it died. The manual said to replace the oil pressure switch, which I did.

It's been an on going thing with the truck shutting off when driving or when I turned the truck off it wouldn't start back up for about 45 min. To an hour.I had it to the dealer twice and they couldn't tell me. The problem wouldn't happen all the time. It could be twice a week, twice a month or twice a year, so by the time I would get it there the truck would be running and they said they can't find nothing wrong because the problem is not happening now. So I started trouble shooting myself. When the truck would act up I check for fuel or spark, had spark no fuel. So I started at the fuel pump relay, replaced that and it ran fine for a while. Then it happened again. So I put my shop manual in the truck and test light in the truck and waited for the next time. When it did I probed the relay plug and it was fine and when it came to unplugging the relay when the truck was running that's when I found that the oil press switch was bad.
May 16, 2012.

On some of those trucks they had issues with a engine ground. For some reason it used the distributor base as the ground. Next time it acts up take a piece of insulated wire and make a ground from the engine to the chassie have someone to turn the key on and you listen to see if the fuel pump turns on. Also have you had a engine scanner connected to it? Does the scanner and the pcm communicate? If it doesnt you may have a computer iussue the fuel pump driver may be malfuntioning in the pcm. Also you may want to get a repaire manual and check all your computer grounds if one is loosing its connection that could be the issue. I hope this helps with your problem.

May 16, 2012.
There should be a ground cable form engine to body at back of right cylinder head as well as one from engine to frame. Atruck tis old may have a bad ground cable from the battery especially if you see corrosion at he terminal end on the battery.

May 16, 2012.