I recently had my pickup die on me while backing out of a driveway. It just died like it ran out of gas, but then fired right back up. So I was thinking maybe the fuel pump is going bad on the front tank, switched to the back tank and it died again sometime later. When I got home I did some pressure tests and I would like to know what you guys make of them. I also checked for both KOEO and KOER codes and didn't have any except for the code that comes up for smog pump removal, I cant remember the number, 331 maybe?

Idle w/FPR connected: Front tank-32 psi Rear tank-32 psi
WOT burst w/FPR conn: F/T 33 psi R/T 33 psi
Idle without FPR connected: F/T 40 psi R/T 41 psi WOT same readings as idle
Idling under load (A/C on, transmission in reverse with parking brake firmly applied): F/T 34 psi R/T 34 psi -- I did this test because this is the condition that it died in.

To me that looks like the pumps are alright since front and rears are the same, but I don't know what the pressure readings are supposed to be so maybe FPR is bad. I thought a WOT burst should put pressure at 40 psi because there would be no vacuum to FPR but what do I know.

All this is for a 1995 F150 with a 302 and dual tanks. Thanks!

 

I dough that your fuel system had anything to do with it dieing.
The KOEO & KOER would not tell us anything in this case.
Did you have any CM codes?
The CM codes is what you are after.

 

Your pressure readings look fine, the WOT test should produce the same numbers as removing vacuum from the regulator but only if it's super short throttle blip... enough to fully open the throttle plates and drop vacuum to it's minumum but not long enough for the motor to actually rev up very much, so more of a quick stab of the throttle. If you hold the throttle at all the motor will build vacuum and fuel pressure will drop again.

 

There weren't any CM codes either. I always forget those codes because they come after the KOEO codes so I think they are the same thing.

So do the pressures look good or are they a little off?

A little more history. The day it died it was probably 110 degrees out and the engine had been running for about 5 hours straight with a lot of idling time. Also it hasn't been starting real good when the engine is warmed up. Sometimes it won't start the first time and I have to floor the pedal to get it started like it was flooded, and sometimes it kind of just sputters to a start, but every morning after its sat all night it will start perfectly. I've checked the ECT and ACT sensors and they come out reading exactly where they are supposed to.

 

Conanski, that WOT test is exactly how I did mine, I opened the throttle all the way really fast and watched the pressure gauge the whole time and it never went above 33 psi. So is that an issue. I have noticed decreased fuel mileage lately and not quite as good of performance.

 

Bump, to see if anybody has some more information.

 

I will go ahead and tell you what you all ready know then.
You either have a very slow (sticking) FPR or an poor fuel supply not able to supply enough quantity (pinched line or bad fuel filter).

 

Ok so the things you mentioned, would that also cause the hard starting when warm?

I did another test to see how fast it builds pressure. First I released the pressure at the schrader valve, just till fuel stopped coming out. Then I put my pressure gauge on it. Then I just cycled the key on so that the fuel pump would do its usual prime before starting. First time I primed pressure went to 9psi, second time 15psi, then 22 psi, then 30 psi, then 36 psi, then 38psi, then finally 39 psi.

To me this seems like it took too long to reach the high pressure, would this also stem from a sticky FPR or pinched fuel line, or could it be something completely different?

 

Well that would not be the FPR as it should be closed all the time you did the test.
You may also have sock filter inside the tank that is plugged.

Of course it could be something completely different as sometimes the my crystal ball gets cloudy and I can not see the problem item clearly.