Rear diff Service questions

[danno2944]

Pre prime without turning over is not even 5psi..

Turning it over FP Rose to 60psi, dropping 2 lbs in first min, will check again now.

10 mins later 56psi

 

[donalds]

Is my fuel pump bad 1999 ford explorer shoc 4.0. Lots of pictures on the replacement

Read this I had just about the same problem

The repair starts on page two

 

[danno2944]

I have read that thread thanks.

It is just I have no start, so no running test?

With preprime at 5psi I am sure that is a problem.

Just dont know how turning it over it jumped to 60 and has only lost 8psi in 30 min. It should start if it was able to build pressure? Which it did and died immediately this morning?

Real question is whether the fUel regulator is needed as well??

 

[danno2944]

Bled pressure tester, preprime is going to 60 psi now? Retried 55psi drained retried 45 psi than """" 62psi.

I am leaving at 62psi to check leakdown again? Check back soon

Holding for 10 mins at 62,

I just read that if preprime is at 60psi the fuel pressure regulator is the culprit, oNviously I will replace entire fuel pump assembly.

 

[donalds]

Sounds like the pump is fine at least to start and idle look for a vac leak

 

[donalds]

Have you done intake gaskets
Are all the vac and vent lines plugged in
the one on the air intake tube
Did you clean the iac valve
The throttle body

 

[danno2944]

All those repairs mentioned were done before winter and truck has been driving great since.

Won't start though, must be spark I guess, didn't think that would be since it started and stalled.

I read 60psi at preprime is sign of a bad fpr, but it should start?

 

[danno2944]

Really was convinced it was fuel pump, not sure what it could be?

 

[CDW6212R]

The 99 and newer Fords require about 60-65psi, under 60 and there's likely something amiss with the pump or lines. Have you ever had a CEL P0174 code, or similar? My 99 had a tiny split in the rubber line at the fuel pump. New pumps should come with a length of high pressure hose to replace the in tank sections. The Bosch pump on eBay was $45 total the last time I checked;
NEW Bosch Electric Fuel Pump Kit 69128 Ford F150 E150 Contour Explorer 1988-2004 | eBay

Place a large old rag over the pressure schrader valve before depressing the tiny pin, to let excess pressure out.

 

[CDW6212R]

My 99 was testing at about 60psi three times over six months, and finally tested at 55psi one day. That 60psi level is "okay", but under that is a good sign that some pressure is not getting to the injectors. My truck ran fine until that last day I got it showing 55psi, it had a slight power loss at higher rpm's. That was from the hose leak at the FPR, that regulator is very reliable. If your pump is old, and the filter is not old, it's a good time to replace the pump, and the short rubber hoses there too.