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Hi, JD here. I have a 1997 K1500 4x4. . parts new. Fuel pump, spider injection, new fuel regulator, crankshaft sensor, temp sensor, distributor,new plugs,wires, new MAP, MAF, new steering box. Truck was running good. Parked it for 3 weeks to get new steering box on. Truck starts right up. Idles ok. Was missing some. Try to move it. Bucks and jumps won't pull itself.. backfires in intake. Won't take fuel. DIES.. put fuel pressure gauge on it.. 12 pounds of pressure is all I get. It should not start at all. It's supposed to have 55lbs to start.. I'm going nuts.. I've checked fuel relay. All is fine.. could it be ground problem?? Truck has been 80 miles on new fuel pump.. please help!!!! Thank you JD
Could be, unfortunately it's hard to get to the ground location with the tank in (unless it has a flatbed) so you will probably have to drop the tank. The test is easy enough using a DVOM check voltage on power wire and ground wire while you back there , on a side note pump failure is also a possibility I wouldn't rule anything out just because it's nearly new.
Tapatalk don't open the video for me. but I had thought about current however all the testing I did using current clamp wasn't definitive enough to call a ground problem or a bad pump as both would/could cause low current
Ben wrote: Tapatalk don't open the video for me. but I had thought about current however all the testing I did using current clamp wasn't definitive enough to call a ground problem or a bad pump as both would/could cause low current
I haven't watched the vid either but the description mentions measuring pump RPM. That's done by 'scoping the current and measuring the time across, usually, 8 commutator segments.
Low voltage across the pump will give low current and low RPM. A bad pump will be low current high RPM or high current low RPM depending on what's wrong with it.
If you can't get to the wires unbolting the bed and moving it back is a lot easier than dropping the tank, especially with a full tank.
We replaced a fuel pump on a 97 GMC with a long bed and we took out the eight bolts, 4 on each side, and disconnected the rear light harness and just slid the bed back and rested the back end on a 55 gallon barrel.
