fuel pressure is low

[1986 danger ranger]

truck runs, but likes to stall if you let it idle. Idle is also inconsistent. has no power (not that it does anyway lol) and will sometimes hesitate/briefly sputter if you mash the pedal from an idle. When it doesn't sputter, throttle response is fairly good

Fuel pressure is a contant 26psi running at idle. It MIGHT get to 32psi by the time it revs to 4k. if you flick the key in the run position sometimes you get fuel pressure, sometimes you don't. IIRC you more often than not, won't get pressure. When you turn to key to the run position, you can hear the high pressure pump energize.

Just changed the fuel filter. what a pita. and it looked like it had never been changed. I had rust and water in the filter housing, and the filter itself literally fell apart just trying to get it out. fuel pressure is unchanged though. still 26psi at idle

Next obvious issue is either one of the fuel pumps, or the regulator. I'm thinking it's one of the pumps but would like an educated guess as to which one it might be based on my symptoms. After all, the pumps aren't the cheapest and these are older, aging vehicles. Around here the cheapest I can get the high pressure pump for is $165!

I'm not a gas guy. I know diesels, and more specifically to that, 12v Cummins motors. Any suggestions would be greatly appreciated!

Thanks guys

 

[Earl43P]

Try RockAuto.com for better FP prices.

I'd pull the input line off the frame rail pump and see if the in-tank pump is transferring fuel. Then I'd consider a new FPR and high pressure pump.

I'd also check the power and ground at the frame rail mounted high pressure pump. Low power from a poor connection would = low pressure. Could be as simple as a bad FP relay with fried contacts.

 

[1986 danger ranger]

and when I search it I keep coming up with a second fuel filter (canister style) that is in the line as well? what's the deal there? is there actually a second canister style fuel filter somewhere along the line or what?

and thanks for the headsup on rockauto. I've heard they are about the cheapest place out there, but never used it. Just looked at the prices and yup, that's where I'll be getting my parts from.

 

[1986 danger ranger]

anyone know about this second canister style fuel filter?

 

[Die.Fledermaus]

Well I have learned to ignore the TFM/catalogs on the in-line steel filter, all I can find on my 1986 B2 is the "old oil filter style" filter element.

 

[Jeff C]

U have fuel issues, I have answers...

truck runs, but likes to stall if you let it idle. Idle is also inconsistent. has no power (not that it does anyway lol) and will sometimes hesitate/briefly sputter if you mash the pedal from an idle. When it doesn't sputter, throttle response is fairly good

Fuel pressure is a contant 26psi running at idle. It MIGHT get to 32psi by the time it revs to 4k. if you flick the key in the run position sometimes you get fuel pressure, sometimes you don't. IIRC you more often than not, won't get pressure. When you turn to key to the run position, you can hear the high pressure pump energize.

Just changed the fuel filter. what a pita. and it looked like it had never been changed. I had rust and water in the filter housing, and the filter itself literally fell apart just trying to get it out. fuel pressure is unchanged though. still 26psi at idle

Next obvious issue is either one of the fuel pumps, or the regulator. I'm thinking it's one of the pumps but would like an educated guess as to which one it might be based on my symptoms. After all, the pumps aren't the cheapest and these are older, aging vehicles. Around here the cheapest I can get the high pressure pump for is $165!

I'm not a gas guy. I know diesels, and more specifically to that, 12v Cummins motors. Any suggestions would be greatly appreciated!

Thanks guys

OK, I have 87 Ranger and just went thru the same set of problems you are . I hope this helps you. On account of the fuel pump is still working, but cant keep enuf fuel pressure to run for more than a few minutes,but not enuf pressure to run under a load, this tells us the fuel pump is still functional, this is good,right? Right... A fuel pump either work's or it doesn't.What I did was drop the fuel tank removed in tank pump and saw immediately that sock or screen on pump was shot and, there was some stuff in the tank, from 23 years of use, 24 in your case. well i cleaned out the pieces of tin foil and sand and whatever else . replaced the sock/filter and bolted it back up. the sock cost me bout 10.$ verses around 180 for new pump assembly as I'm on a tight budget as I believe all of America is. Anyways.... Then i went and replaced the fuel filter , and replace the In tank fuel sock/screen, now truck runs great. If u can afford a new pump I'd say replace it as the tank is not easy to remove and since your going thru all the trouble to fix , may as well replace w new parts but that's your call.... anyways my 87 stx has 2 fuel pumps, Holy shit! yep 2 of em . don't know all details on 86 but would assume your does to, get a chiltons manual and the answers are there 4 sure.Hope this helps you. Jeff