Today my truck just lost power as if it were running out of fuel. It will run fine at a light load but no more than that. Plugged fuel filter? Liftpump going bad?

Thanks for any help,
Brian

 

I dont think they just die like your describing "all of a sudden"
I would however check your FF. When is the last time u changed it? Got a fuel pressure gauge? install one.

 

Sorry, I guess I should have added more. The power loss wasnt " all of the sudden" , but over the course of a few days. It was acting up like a bad load of fuel. Hard to start sometimes, ran a little rough after started other times. Then I went to hop into traffic after work and it had no power after say half throttle. If I came to an uphill the truck would slow and as I gave it more throttle it would act as if it were running out of fuel. 35 mph up some very mild grades I will change the fuel filter tomorrow. If the problem persists I'll be back.

I'm also curious if the truck will still run with a failed liftpump? If so, how well will it run? Does the Injection pump also create a suction that could pull fuel from the tank? Sorry if these are really newbie Q's but I just dont know the answer.

Thanks for any info you can spare.

Brian

 

For your pocket book, I hope it is the lift pump and not the injection pump. The injection pump on its last leg on its way out will give the same problems you mentioned. Had the same issues and mine acted the same. Replaced the fuel filter, then the lift pump, and then finally figured out it was the injection pump the whole time. Theres also a filter in your tank, but from what you described, I say ip. Whats the color of the smoke coming out the exhaust when its missing and shaking and feeling underpowered???

 

If it persists after changing the fuel filter then look at the lift pump next or even the fuel lines.

Mine was acting like yours - loss of power going up hills or would just run out of steam on the road. It was the lift pump for me.

 

my lift pump went out as well, you might be able to see a rise in oil, where it could be leaking. but when mine was going out it was over about a month or two course, just getting worse. but it ran , but it would have very little steam.

 

The VE pump can draw its own fuel. My bud found out the hard way, we went clear to the top of Vermont and back (14 hour trip) on a bad LP!! oh yeah it was BFE, middle of the night, and -20* to 0* outside depending.
luckily his IP survived like this for a couple weeks. The only reason we found out the LP was bad was cause he wanted to check the LP fuel pressure, due to the truck falling on its face in the upper RPM's.

 

Good to know info, thank you. I'm not driving it to work today because I feared I might melt the IP. I think I'll pick up the new LP and filter, start with the filter and go from there.

Thanks again guys.

Brian

 

The design of the factory fuel plumbing, on these engines, doesn't lend itself toward simple quick fuel-pressure checks with hand-held gauges.

Without any place to easily tap fuel pressure, any diagnosis is merely educated guess work.

I replaced the hard lines between lift-pump/filter and filter/injection-pump with 3/8 rubber, doing away with the restrictive banjo-bolts in the process.

Then, I spliced in a TEE fitting, with a gauge port, and installed a dash-mounted fuel-pressure gauge, between the filter and injection-pump.

The gauge eliminates most of the guessing game.

As to the fuel-filter, I have seen dual-filters, on big engines, stop up in minutes from bad/dirty fuel.

We had a local, very busy, fuel stop to have the main draw-line, between the fuel-pumps and in-ground tanks, develop a huge split in the line.

This place is built on top of a swamp.

When this split occured, almost every truck that fueled there shut down within five miles, with fuel filters full of water and mud.

 

You'll probably eventually find the banjo bolts make for a more reliable longer-lasting fitting. But it does help to open up and chamfer the holes a little when you have them out. Just be careful not to take off too much so they become weakened to the point they break when you put them back in. You can also get what Genos calls "high flow" banjo bolts. Same thing, I think.

 

Filter first, then lift pump. If it's not them, you're still out less than $100.

 

.........it was the fuel filter. Yaaaaaa!!!

I'm going to use my flaring tools and splice in a tee for a fuel psi gauge.

Thanks again for the help.

Brian

 

While working on my IP I discovered my lift pump was completely bad. It wouldn't pump a bit but the truck was still running and had no power loss. I could still drive 90-100 mph. The IP has a vane pump that will pull fuel as long as it doesn't lose it's prime.

The only sure way to check the lift pump is to check the pressure. A good check is to remove the bleeder from the output banjo of the fuel filter and then work the lever on the pump. You may need to bump the engine so the fuel pump cam is in the low spot. If you can hand pump good spurts through the filter the pump is probably OK.

Edwin