i got a 94 deisel 3500 i was reading the newbie thing anyways went to check the lift pump operation, the pump on the 94 does not prerun with the glowplogs apparently, so i had the engine running i cracked open the t valve for about 3 seconds fuel poured out of it and the engine did not burp or stutter it never missed a beat..... did i have the valve open long enough? and does this mean my lift pump works?
If you get fuel with the engine running and it does not stall right away I suspect that the LP is working.
A better test would be to hook a fuel presure gauge to the line connected to the tee-valve and check running pressure-that will tell you for certain if there is pressure at that point and how your lift pump is working.
94-95, the lift pump will NEVER pre-run. It is like that from factory. Nothing to worry about. You can mod it such as Kennedy LP/OPS harness will pre-run with key "on".
In this same year, the OPS controls the LP during engine run. So bad OPS can cause LP not to run. This is the part of the OPS which controls the LP not the one to the gauge.
I just replace the lift pump on my 1994 6.5 turbo diesel because it wasn't running when i had the truck running so i replace the pump and still same problem. i also replace the fuel pump relay. Does anyone know what it could bo wrong whit it?
Today. I got to replace the OPS on my truck and my lift pump its working again. thaks for all the help guys.
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