To rehash some stuff that was another thread, my GF's Blazer ran fine up until last Sunday morning. Jumped in, turned key and engine just spun over and over, wouldn't crank.....

Squirted some starting fluid down breather, it fired right up.

I checked for fuel pump noise when key was in ON position and heard nothing. The original pump may have been a littl noisier than others, 'cause I could hear it with the car running.

Swapped out relays, tried pump prime terminal, checked fuel line pressure at test port (0 psi), banged on gas tank. Still wouldn't crank.

Towed to shop, pulled tank, removed pump assembly. I ordered another pump assembly (AC Delco MU1733) and when it came in compared it to the original.

The new pump is about 1 1/2 inches shorter than the original and the float arm is positioned differently. Talked to several different parts houses and nobody can shed any light on this. Repairs are on hold until I can figure this puzzle out.

 

2 door and 4 door fuel pumps are different, which do you have?

 

The Rock Auto site lists two AC Delco pumps for the four door, one with 18 gal fuel tank (MU1733) and one w/o 18 gal tank (MU1772). I got the MU1733 and there is some difference from the original pump in the wiring harness as well as other aspects.

 

Is the tank plastic or steel?

 

You say you "Talked to several different parts houses".
My question is did you speak to RockAuto. There very good at solving problems like this on the phone. Remember they have a vested interest in your problem other parts houses do not.

 

^^^ X2 Good point.

 

Spitty, I did talk to RockAuto prior to purchase and afterwards. They tried to be helpful, but were not too familiar with the differences between the two pumps. A good bit of the confusion is the way the AC Delco pump is listed on the RockAuto site.

MODULE,F/TNK F/PMP(SENDER & PUMP) 4 DOOR; w/18 GAL TK(NE2); INCLS SEAL; w/o LOW LUBRICITY FUEL SYS SENDER(K55)

If they had added "plastic fuel tank" I would have known that the other pump (MU1772) was the correct pump for installation in a steel tank.

The RockAuto listing for the Delphi fuel pumps makes that clear. I also found a Delphi tech sheet that has some photos that make the distinction. See below

http://www.delphivictorylane.com/img...%20article.pdf

The last CSR I spoke with at RockAuto indicated that there would be no problem with a return, so back it goes tomorrow.

A tip of the hat to Captain Hook for figuring out the crux of the problem