They did not say there if were MAP DTC's. Just said it was shorted out? I did pick the truck up and completed a leakdown test today. When warm the truck makes 60psi. after ten minutes it leaks to about 32psi. Definitely a problem somewhere. Any way to test to see if the problem could be in the pump? Maybe a bad check valve in the fuel pump ?

 

If the MAP shorted out, it would set a DTC and turn the light on, guaranteed! If there was no check engine light on, (and it works) I would question the work.

Key ON, engine OFF, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes. If you're getting 60psi, that is the lowest allowable, but the drop to 32psi is a problem. The next step in diagnosis is to adapt the fuel pressure tester so it will connect directly to the outlet of the fuel filter. All fuel pressure and flow must "dead end" at the tester. When the pump is running, pressure must be 73psi to 108psi and must remain above 55psi for at least 10 minutes after the pump shuts off. It either part of the test fails, make sure the pump module is getting battery voltage, (grey wire) and resistance to ground, (black wire) is less than 5 ohms at the module connector. If those both check OK, the pump needs replacement.

 

Replaced fuel pump with a Delphi yesterday. Got my truck back! Haven't had it on a pressure gauge yet but it cranks up cold or hot everytime. I appreciate the help from everyone!

 

Cool, thanks for posting back with the fix. What about the MAF sensor and the $50 you spent on a totally incorrect diagnosis? The one that said the fuel pressure was good and the MAF sensor was bad.

 

Well that 50 bucks for me just just money down the drain. There are no codes and apparent MAF sensor is good. However, I know not to take my vehicles to that particular shop anymore.

 

Expensive lesson! I guess it could have been worse though. Check with us first next time

 

1.if i may.
my 95 has been acting up for a few months, ive given her a full tune up and tonight my son brought her home and she died in the driveway. with a code of p1351
its about 3 degrees here and she will crank over but wont start.
I have checked these items.
spark at coil and plugs, fuel delivery but not the pressure yet, too cold to do it right now.
pulse at the injector harness,vcm harness plugs and all ignition component plugs.

Any ideas, please tell me because im running out of cash and this thing is parked on top of my last nerve.
thank you

 

Here's the thread for diagnosis.

When you get the fuel pressure and leakdown numbers, I'm sure there will be more ideas.

 

pressure with key on engine off 60 psi
pressure after 30 min was 56 psi
initial pressure was at base limit even while cranking engine over.
but it was that when i put in the pump and sending unit 14 months ago.

 

Your 1995 is not the same as the original posters 1996 vehicle. Best to start a new thread so we can give you the correct diagnosis procedures.