2001 Blazer, ZR2; Purchase a KAL fuel pressure gauge off ebay. Connected to fuel pressure test port, turned key to on/run, no pressure indication. Did not hear fuel pump run - don't know if I should. Started the engine then the fuel pressure builds up slowly, maybe 5 to 10 seconds, to 52psi and remains steady regardless of engine speed. Drops to zero after engine is turned off. Repeated the above several times and always have the same results. I am really puzzled by the slow pressure build up??? - thanks

 

Your pump is either dead or you're not getting power to it or the ground is no good. By the master cylinder there is a red jumper wire for the fuel pump. Run a wire from the positive on the battery to the jumper wire.

 

For the umpteenth time:

96+ Fuel System Diagnosis

 

Thanks for the input, couldn't find the RED wire.

 

There is no red wire. That's only on first gen trucks, IIRC.

 

I have one on mine.

There is a test terminal next to the fuel pump relay, that you can put 12v power to , and should have power back at the gray wire on the fuel pump connector.

2001 PDF wiring diagram that shows "fuel pump prime connector" at the top right
https://www.box.com/s/11e02d5fbc14b308efb7

 

I did figure out where the test connection is, I saw it on the schematics, but none I have seen indicate where it is located. I was able to measure fuel pressure at the filter output. Drops to less than 10psi immediately and then bleeds off to zero. So it's off to the parts store to get a new fuel pump. Thanks Everyone - more later

 

WOW! Not something I would want do more than once. Got the fuel pump replaced. One thing I found was the old fuel pump, which was a Carter, it had been replaced. The white plastic had almost fused to the nylon fuel line connectors. In fact, two of the inserts that hold the spacer and O-Ring into the nylon quick disconnects were stuck to the pump and were pulled out of the connector. I gently removed them and reinserted them into the quick disconnect. There was a green plastics ball in the tank, which I think should be in the fill tube, I removed this and several large (1/8") chunks of solder and a one inch piece of wire with a solder ball on it - who knows.

So fuel pressure; Running pressure is still around 55psi, was at 30psi after 10minutes.
No hesitation, starts right up now - used to take a couple starter cycles.

Lessons learned,
1) for a two door do not try to remove vent and filler tube from the tank, as per GM manual - just unscrew the three screws that hold the fill spout to fill door assembly.

2) don't forget to bring whole bunches of patients

Once again, thanks to everyone for your inputs

 

If you didn't install an AC Delco or Delphi pump, you'll be in there doing it again shortly. Aftermarket pumps don't make the grade on these vehicles, as you found out with the carter pump The most common mistake people make on these is to try to save some money and install an aftermarket fuel pump. If you want to save money, go to the bank, if you want your vehicle to run properly, install an AC Delco fuel pump.

The fuel pump test terminal is exactly where the schematic shows it.... in underhood fuse panel, right next to the fuel pump relay. It's a single, unoccupied female terminal, smaller than a fuse socket.

Might want to check fuel pressure and leakdown again, GM does not publish any "engine running" fuel pressure specs for this fuel delivery system. Engine off, apply battery voltage to the fuel pump test terminal, pressure must be 60psi to 66psi while the pump is running. Remove voltage from the test terminal and fuel pressure must remain above 55psi for at least 10 minutes.

 

As to the location of fuel pump test terminal, all the schematics I have seen show that it's located somewhere on the fuse/relay box, although it does make sense to locate it as close as possible to the relay. I have yet to see a diagram showing where that terminal it is. I have the GM 2001 Service Manual Set, it states to monitor fuel pressure for 1 minute and that it should not drop more than 5psi - difference year or manuals?