Engine/Transmission (1994 - 1998) Is Fuel 22PSI OK??????????????????????????

[guldam]

My life pump/fuel pressure issues

Pulled the pre-heater off today, put the strainer and bowl back on, and interestingly my fuel pressure was now more constant. At first it was about 10 psi with very little fluctuation, and then it would suddenly jump up to 20psi. It would do this for a few times and then settle down to 10psi. Hmmmm.



Before the needle would go from 10 - 20psi bouncing, bouncing, constantly.



So I pulled off the elbow hose at the stainer and lift pump, and put on a 6 foot piece of 1/2 hose, and installed a clamp. Stuck the hose in a 5 gallon jug of biodiesel, pumped the heck out of the primer, and started the truck up. It took an awful long time to pull fuel from the jug and when it did it never did fill up the hose. Fuel pressure was a rock steady 10psi.



I think my lift pump is weak.



And now I'm going back out and stick in a Chinese pump.



Joy!



GulDam

 

[guldam]

Update...

Spent four hours replacing the lift pump today. Figured out yesterday I couldn't get that fuel line off at the pump, so I took if off at the fuel filter housing. That was fairly painless. Removed fuel filter. Why is that o-ring on top of the fuel filter always loose and looks stretched out when I change filters? I try to gently seat it, but am not entirely sure it goes in the way it's supposed to. Has this been a part of my problem?



Then I removed the fuel line at the pre-heater, removed my brand new 90 degree elbow hose and I swear it felt like it was five years old after only replacing it yesterday and putting 50 miles on the truck. Is BioDiesel that rough on rubber parts? I did put a little dab of silicone grease to help the hose slide on to the barbs. Hmmm.



Unplugged the wiring to the pre-heater. Unbolted the lift pump and it, and the preheater came out one piece at a time from the top of the engine. Yep, I did all work from up top.



Unbolted the top fuel line, and the bottom elbow fitting from the old Made in USA Carter pump, and transferred it to the new Made In China Pump. Coated threads with Teflon pipe sealer. Put a little gasket stuff on the gaskets so they wouldn't fall off when putting the pump back on. Put a dab of grease on the plunger end, and climbed up the ladder and laid down on the engine and cursed, swore, and said bad words as I tried in vain for an hour to the threads started on the lift pump bolts. Bumped the ignition until I could finally get things in place. Put all the other stuff back on, and pumped and pumped the prime button, bled the air out of the filter, and pumped some more.



Started the truck and I had fuel pressure. It was steady at about 16 psi. . hmm. Revved the engine and the pressure increased up to about 30psi. Hmmm.



Took the truck for a drive, and some of my missing power was back. But not all. Pressure at idle stayed below 16 and after driving it went back down to a steady 12psi.



Scratching my head again.



Pulled off my new overflow valve and put back on my old stock overflow valve that I'd stretched the spring out to 1/2". Immediately had gobs more Fuel pressure at 20-25psi, but the needle of the fuel meter is bouncing all over again.



Gave up for the night and cleaned up my mess. I'm just about to give up and take the truck to a shop.



Boost doesn't want to go above 20lbs. EGT doesn't get above 1000 degrees.



GulDam

 

[WDixon27]

without something to snub the pulses of the lift pump the gauge will bounce with the pump pulses, it will break the gauge after a while, when i first got my truck and added gauges mine didn't bounce, but it also didn't pump fuel worth a damn either, i put on a new lift pump and it still didn't bounce but on the way back from a 2200 mile round trip it started the bounce, not sure if the pump finally broke in or what started it to acting normal but a pulse is normal on a 12v

 

[guldam]

I have a new torktek snubber installed. By pulse, I mean the needle jumps in 10 or more psi increments.



After replacing the hose elbow and ditching the pre-heater and finally the lift pump, and the filter, the needle calmed down. But the fuel pessure was still low. Put the old overflow valve on and the pressure dramatically increased, but it's back to the swinging needle. Power is still not back.



Going to just drive it and take a break.



I wonder if burning b100 is trashing all the hoses and o-rings and I'm just chasing my tail.





Guldam

without something to snub the pulses of the lift pump the gauge will bounce with the pump pulses, it will break the gauge after a while, when i first got my truck and added gauges mine didn't bounce, but it also didn't pump fuel worth a damn either, i put on a new lift pump and it still didn't bounce but on the way back from a 2200 mile round trip it started the bounce, not sure if the pump finally broke in or what started it to acting normal but a pulse is normal on a 12v

 

[guldam]

Another thing... . The new lift pump is not clicking it's little heart out. Old was making a racket here and there. CLick! Clickclickclick. . CLICk!!!

Guldam

 

[HEMI®Dart]

Quote: "Removed fuel filter. Why is that o-ring on top of the fuel filter always loose and looks stretched out when I change filters? I try to gently seat it, but am not entirely sure it goes in the way it's supposed to. Has this been a part of my problem?"



I noticed this too running B20. I don't see it running str8 #2.



Same goes for the elbow from the lift pump to the strainer. Mine started to leak after a couple of years w/ B20.



I wish I could help. I am out of ideas.

 

[HEMI®Dart]

I bought I snubber from TST a few years ago. Samething. Needle bounces all over.

 

[The patriot]

My filter gasket suffered a little "shrinkage" when I was running WVO there for a while.

 

[HEMI®Dart]

My filter gasket suffered a little "shrinkage" when I was running WVO there for a while.

Expansion here.

 

[fest3er]

I had a NAPA filter where the o-ring expanded after 'short exposure to fuel. I replaced it with a Cummins filter.

After sitting for months on my work bench, the o-ring is back to normal size. I think the o-ring on (certain) aftermarket filters is not designed for #2 oil.

 

[CToney]

I finally installed the overflow valve from Tork Technology on our one tractor and our combine. The tractor's fuel pressure was at 25 psi idle and at 34psi at rated speed. Our combine needs new fuel filters and or electric or mechanical lift pump as it has both. It was 15psi before and 16psi after new overflow valve. Too bad they are both parked for the season. I am sure they would run better. Their valves look good and the price is half that I paid for a new bosch a few years ago from a local diesel shop.

 

[guldam]

After all the work I did last weekend my new found fuel pressure appears to have weakened one of the hoses behind the engine, because I now have a leak there I didn't have before. Sigh.

Some company like Geno's really should consider sourcing the very best fuel line, o-rings and seals for a complete fuel system tune up / rebuild. I'd appreciate seeing these items be extreme duty and designed to work with B100 and WVO. I feel like a cat chasing my tail. I fix one silly rubber thing and another breaks right after.

I emailed FleetGuard asking about either filters with o-rings and seals designed for BioDiesel, and/or measurements/specs of all the o-rings on the filter I use. I got nothing but lame and lazy answers.

GulDam