HELP!!!! fuel presure issues

[stngllhm]

Hi every one been searching your site for a few days trying to find answers and found quite a few so thanks. But I'm still not sure what's wrong with my 92 ranger 4.0 I was having a stalling or cutting out problem which I have traced to only having 28 psi of fuel presure. I changed the filter and fpr and I'm trying to stop just throwing parts at it. When I disconnect the vaccum line on the fpr I get about 34 psi. I grounded out the pump terminal in the test connector and still it won't go higher than 34 psi. And if I let it sit it bled 10 psi in 15 min. I disconnected the fuel line right before the filter and hooked my gauge up there and jumped the connecter and got it up to about 58 psi and it has bleed 18 psi in an hour. Also I have no viseble leaks so I assume the bleed of is in the tank. Is it my pump or do I need to keep looking. Thanks for the help.

 

[Roadrunner777]

I would try and do some volume tests, before the filter, and maybe the output of the FPR. What is the pressure with the FPR vacuum connected now? I know you said it was 28 PSI before changing the filter and FPR; I'm wondering if it changed.

 

[stngllhm]

Bought the presure gauge after replacing those items, so 28 psi is after changing. Yea I could have saved myself the money if I had bought the gauge first, but now I have it for next time I also replaced the fuel relay.
Could you explain the volume test how much should I get do I just piont the hose into a pitcher?

 

[Roadrunner777]

Essentially, yes, just put the hose into a container and jump the connector to run the fuel pump. You should get about a pint (16 ounces, 475ml) in 15 seconds. See if you can figure a out a way to do this at the fuel return line of the FPR. If you don't get a pint or so, test again before the fuel filter. Your pressures look good, which means we either have a volume issue (a pinched line, etc...), or we are not catching the pressure problem 'in the act', or it is something else that seems like a fuel issue.

 

[stngllhm]

Your pressures look good, which means we either have a volume issue (a pinched line, etc...), or we are not catching the pressure problem 'in the act', or it is something else that seems like a fuel issue.

I had been led to believe that 28 psi was too low. Isn't it suppose to be like 35 - 45 psi.

 

[Roadrunner777]

I'm running great on 30 PSI...

 

[stngllhm]

So once you said my presure was ok I started looking for other causes I cleaned the maf and I got better but was still there so I bought a new maf no improvement. Then I seafoamed the moter twice and it does run better but I still have a miss/cut out below 3000 rpm once the moter is warmed up. It doesn't do it when running in open loop. Any ideas

Sorry got mixed up on open and closed loop. It doesn't do it in open before everything is up to temp.

 

[stngllhm]

Any other ideas or places to look

 

[Roadrunner777]

You said it doesn't do it when it is running closed loop. That can be a big clue, I just want to understand your conclusion. How did you decide this to be the case?

 

[stngllhm]

Sorry I got mixed up on which is which it doesn't do it in open loop.

It only does it once everything is warmed up to normal temp. I will try disconecting the o2 sensor so it stays in open to verify what I said is true

 

[MrShorty]

Did you measure the fuel pressure (28 psi) when it was stalling/cutting out? I have seen enough "intermittent" fuel issues that I think it is important to test the fuel pressure when the symptoms are occuring.

Before you start disconnecting sensors, I would suggest you pull codes from the computer and see if there is any clues there. Once you start disconnecting sensors, we won't know if the code was generated because something was disconnected.

 

[stngllhm]

I just pulled the codes I got 111,111 long pause then 157,157 this was just the key on engine off. 157 indicates a maf right? I just put a reman from orielly on what's the chance I got a bad one(I did pull the battery cable to reset the computer after changing the maf). Also the miss stutter only happens while driving how do I check the presure then

 

[Roadrunner777]

This site has good diagnostics for MAF sensors, voltages and grounds:

http://easyautodiagnostics.com/ford_maf/maf_sensor_ford_1.php

 

[stngllhm]

Thanks for the link on the maf it checked out good