lift pump

[DeepRoots]

so truck has been giving a mild surge last week (bout 450miles this week).
also, once out of every 15starts it'd crank for ever with no fuel until it finally popped.... for no apparent reason.

anyway, today I filled up, ran the last errands since I finished at the jobsite....
ran fine in town. Got out of town on the way home, 55mph was mildly hard, and the truck had a mild surge. I pulled over, no massive leaks.... fuel filter is 600miles old.

Got it home even tho last 10 miles were 35mph on country roads... it barely did any faster than that.

threw on a pressure gauge, 1psi fuel pressure at idle.... 1in vac at 1500rpms.

I'm changing the mech lift pump in the morn. If anyone else has a better suggestion, feel free to throw it at me.


least this could solve that weird intermittent surging I couldn't figure... (i thought it an air leak).

thanks
Drew

 

[Exekiel69]

Unless the veggie is clogged in the lines, which in your case I very much doubt, I also think it is the LP. How old/miles is it? Maybe is a good time to put an electric pump, easy to replace.

 

[DeepRoots]

ummm bout 10-15k miles on IP.
clogged lines? impossible, there is only 2inches of shared fuel lines.

no smoke either... if the IP was shot it'd smoke something....

 

[Exekiel69]

No IP I meant LP (lift pump). It really sounds like it since You say 1psi pressure and 1inch vacuum.

 

[Agnem]

Well if you only have 1 psi of fuel presure, then you're problem is upstream for sure. Either the lift pump is bad or you are sucking air with it.

 

[DeepRoots]

uhhhhh found the problem.
The previous owner told me he always had the ford dealer do the work on the truck....
lift pump had been replaced in the past (It was the newer style arm). Unfortunatly one bolt (that pesky one towards the rear) wasn't there. I can only assume it was either forgotten about or only hand tightened.

Guess that explains the intermittent problem. Also explains why the front of the motor was always REALLY oily (I assume the pump was loose for along time before it fell off this week).

luckily it fired right up with no problems. I can only imagine the camshaft has a few dings in it.

 

[icanfixall]

Glad your back up and running plus it didn't require any parts but... Any jerk that will not install a bolt is not a mechanic but a hack. Sure.... Maybe the Frod "mechanic got in a hurry or had the runs and somebody else finished the pump installation and didn't check all the bolts. All 2 of them. Geezs, what if the fuel outlet line was left loose and they told you "that will seal up in time. Let a little dirt and grease cover it up"...

 

[DeepRoots]

*shrugs*
ohh well it worked out.

I'd have been more pissed if it'd broke and trashed the motor.....
I did buy the part anyway, but heck.... never hurts to have an extra fuel pump under the seat.

either way, tightened up... locknuts in place, ready to roll for the next job monday.

gotta build a retaining wall out of about 700railroad ties... should be a blast.

 

[Diesel JD]

Hey, now that you found that problem it will cut your oil consumption in half or more. Maybe it didn't damage anything. A mechanic ^should^ be able to fix a lift pump, but to be fair, that back bolt is a tough one for a lot of folks.

 

[icanfixall]

Its not that tuff. I use electrical tape on the bolt to socket to extension just like the top starter bolt. Pull it off when your done and thats about it...

 

[DeepRoots]

new developments.
after another 700 miles we've developed another problem.
I drove about 300 miles today, went to go set up a propane furnace for someone...
anyway, surging was back, it was mild unless trying to go over 55mph. Feels like there is a blockagefor 30 seconds and than bam, revs up 400rpms or faster for 30seconds.
Truck runs fine under 2000rpms in gear, runs without a peep up to 3000rpms no load (in park).
I havn't checked the fuel pressure on this new pump.

So annoying on the trip out, I pulled over at a gas station, and re-routed/disconnected all my veg oil lines, to make sure they weren't part of the problem. I even swapped fliters (I've got three in use on the truck, one for each tank) Same problem. This is not a problem (that I know of) on veg oil, as I havn't used any since before the lift pump incident.

No smoke.
Problem is not overly obvious when I start out, but 5-10miles of cruising and it gets worse and worse. Shutting down the truck/or idling for a few min fixes the problem for another 5miles.

my thoughts:
IP trashed from running with a dead lift pump (That'd suck since it's a new pump, I'd probably cry)
camshaft lob worn and not pumping the fuel (solution, get a electric pump)
or really bad air leak I can't find.

whenever I get the time this week I'm going to check the IP inlet screen, check fuel pressure, and add some clear line/check for air.

 

[93turbo_animal]

I was having a surging problem and it ended up being that the screen in the end of the IP had a film on it I'm assuming from my use of WVO but I cleaned it as best as I could and it ran great after wards

 

[DeepRoots]

great, that'll be what I do tonight, any tips on removing the ip nose to get to the screen?

 

[93turbo_animal]

I hope this ain't to late but be careful the only reason I did it was because I had seen one taken apart before and knew exactly whats in there I kinda waited to post this hopping you would find a different solution to your problem. First I would double check your fuel preasure again as this is far easier but to get to the filter you have to remove the supply line to the IP and I had to remove the top 2 lines to get my wrench in there but then ther is a allen bolt through a stop that has teeth on it that keeps the snout from turning remove this then I used a soket on the fitting where the main supply line goes to unscrew the snout CAUTION behind this snout is the IP internal fuel pump which is an offset ring with 4 spring tensioned blades if you remove the ring around them they will fly out and you will be pulling the IP there is also a small locating pin that will come out with the stuff in the nozzle this is important you see where it comes out it goes thru the fuel pump ring and into the pump it holds the ring still while the blades spin inside making it pump but the filter is in the snout when you get it out just dump the stuff out in your hand and you'll see the filter then the only hard thing left is getting that little pin to line everything back up but then just put it all back together I started at the fuel filter head leaving all the lines loose till I got fuel working my way towards the injectors bleading all the air

 

[DeepRoots]

i was just asking for instructions
I would pull the IP to do this anyway.

I'm in the middle of a job, so I wouldn't have the time right now.... I did remove the supply line and drain the IP. Hooked back up cranked it over, and removed it again.
Seems that was indeed the problem, as it runs a world better (nice to have my truck back).

only hickup is at 55mph it seems like the truck pushes forward/holds back... hard to feel, but it's there. I can live with that for the moment.

thanks
Drew