GM Truck Club Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter #1
Back in the Fall of 2009, I replaced my fuel pump on my daughter's 98 Suburban with a new AC Delco MU1748. It had symptoms of deliverying pressures around 47-48 psi and basically got so it wouldn't start at all. Went thru the ignition system, FPR, and finally narrowed it down to the fuel pump. Mr. Shorty on this forum was a great help. Now the truck is starting to act up once again. Mostly on cold starts. Warm starts are generally OK. I measured the fuel pressure at the intake and it is about 58 psi. I recall hearing that 60-66 psi is typical range, so I guess the course of action is to make sure the FPR isn't bad (by squeezing on the return line while activating the pump)? I did get the intake manifold gasket replaced last Summer and wish i had done the FPR while in there.
 

·
Registered
Joined
·
7,979 Posts
Well another way to take a look at the FPR with out really having to do to much is to look down the throttle body and see if you see a wached out area between the #4 & #6 Cyls. If so then the FPR is leaking and will need to be replaced. Also if you smell raw fuel after its been driven some when you open the throttle with your head under the hood then that is also another giveaway.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #3
Will not start - suspect fuel pump??

So a couple of diagnostics just done:

1. Fuel pressure at the rail is about 51 psi. I'm using the red fuel pump lead under the hood to test. Occasionally, it will jump up to maybe 54-55 psi.

2. Suburban will not start

3. When I pinch the fuel return line the pressure does NOT jump

4. fuel filter changed in 2009 (when I did the pump)

guessing it is the pump once again - damn AC Delco. You'd figure they would build a better pump than Airtex, etc. BTW, Airtex was the brand that I pulled out back in Fall of 2009. I figured play it safe and go with Delco, MU1748. But they also just have one year warranty.

what do you all think???
 
1 - 3 of 3 Posts
Top