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starved for fuel Lift pump? Tank Unit?

2K views 21 replies 4 participants last post by  D-Rex 
#1 · (Edited)
1996 12v 4x4 stock daily driver---broke down yesterday -driving fine suddenly sputtered and acted starved for fuel, stalled, restarted ran stalled. I have the Tritan marine lines recommended by illflem. I've checked them and clmps they appear OK. My fuel gauge got very funky shortly before this happened but I wasn't all that worried thinking it was the float/gauge thing- and that before to long yeah I should replace that tank unit. (when I did lines I fit under there and could just get 'em done without dropping tank or lifting bed)

I put a new fuel filter on. Didn't seem to have water in old one. Cracked bleeder screw on top of fuel filter and pumped the prime button. I have only done this once before -using the prime button to bleed it--and on that occasion maybe 10 pushes and I got fuel flowing from the screw. This time-- I've done a lot more got nothing moving.

That manual pump button sucks to push, I've got to round up a broom handle.
I've read other posts joking about having to push that primer about a million times to get fuel---- maybe I just haven't done enough yet?

I also am wondering-- with the 12valve manual lift if the tank unit was all shot to hell would it cause these symptoms? How would I know if it was in the tank unit or the lift pump? My feeling was, since tank units gauge is FUBAR maybe other parts of it are too.
thoughts advice?
 
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#2 · (Edited)
You might bump your engine over as the lift pump cam lobe could be on the high side negating push button primer pump action. You could have clogged screen in tank and/or on side of block if equipped.
 
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#3 ·
OK- so I took the shield off the wheel well so I could take a broom handle and push on that manual primer button much more easily. Got fuel running through clean and steady. Pumped quite a bit thru to make sure it didn't die out and that it really was steady flow.

Tightened the nut back up on bleeder screw---I hope I did that correctly--- I loosened the large 9/16 ? nut on the bleeder/bango set up not the smaller blolt head on the tippy top. Anyone tell me if that was right? I've only done this once before and it wasn't till I was done I though...oh crap I remmebr somebody sayin something about "do this not that" on that bleeder ;0(

Very annoying, hopped in to see if it starts....the tow truck driver that towed it for me had left the key in the ON position ;0( Bettery low rrrrrrr rrrrrrr weak weak . I didn't think to check that yesterday when they dropped the truck in my driveway.

I borrowed neighbors buick sedan to ry and jump it see what happens--- in pissing down rain--I still got weak cranking and no fire up. So--- maybe the buick just doesn't have enough to help turn it over / fire up.

anyone know what the best way to go now is--- hook my battery to a charger and go to lunch or call a tow truck to give me a more powerful jump?

I am kind thinkn charge my battery fully with my charger (because I'm pissed they theft it ON and ran the damn things down !) And even if I've got it bled and ready to fire up it could require a little effort and one or 2 start stalls.... fingers fekking crossed.

Checked the fuel shut off solenoid---it seems to be moving back and forth off and run positions.

any further advice based on this info welcome.
 
#4 ·
The bleeder bolt is 10mm, on top of the fuel outlet going to the injector pump. Charge you batteries, but from your other post I'm thinking you have fried the starter. Don't go to a auto parts store, their starters won't last long. More than likely all you need to do is replace the contacts. Larryb - LarryB's Dodge Cummins Denso Starter solenoid kit, 89-2006
 
#5 ·
so have I likely stripped/screwed something up by loosening that nut instead of the 10mm bolt? I'm assuming we are talking about the same thing, 2 bolts/nuts on top of the housing the fuel filter screws into.

If I have frigged it up where do I get a new one?

I have my batteries hooked to chargers--- I guess if they are fully charged and I still get sluggo crank I will know for sure to tap the starter
 
#8 ·
A quick search found these. A local Cummins shop might charge less. The bleed screw has a smaller gasket. Most Dodge dealer parts people will give you a deer in the headlights stare if you ask about banjo bolt gaskets, but you could try.

14MM Banjo Bolt Gasket-Geno's Garage
 
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#9 ·
Thanks GAmes you're the best! Yes-- I am familiar with the deer in headlights stare when asking for 12valve parts....I think they've been sent a memo to pull this crap because the dealership in my town I know for a fact the parts guy has worked there for a million years and I saw him driving a tricked out 12 valve 1 ton :buttkick:
 
#10 ·
Well I am running again---still need to road test---I have a hunch my fuel tank is cruddy and/or my tank unit is not in great condition

I am not equipped to check myself--have made an appointment to get the fuel pressure/flow from the tank checked--- hoping to get little more hint whether I need to go ahead drop the tank clean etc.

Random question---- I'm not one for conspiracy theories but I kinda wonder if a neighbor I'm having trouble with could have put sugar in my tank? I've always *heard* this frigs up a vehicle and is a popular way to screw with someone you have a beef with!---anyone tell what The real deal on that sugar in the tank things is????

Thanks for the help !
 
#11 ·
Mythbusters did a thing about sugar in gas. IIRC, they finally went to the extreme and put battery acid in the gas, or something just as caustic. Sugar didn't hurt anything.
 
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#12 · (Edited)
yeah my guess would be filters would catch many things a asshat might try to put in a tank---and that could stop up a filter which is a PITA but not kill the rig

I started another thread on the topic of things people might try to put in your tank to be evil---I'm curious! There is so much *said* about it
 
#13 · (Edited)
OK- few more questions:

So I got the truck started and running, drove it around 2 days and it is "OK" but I could feel it was not quite itself WOT and pushing the pedal down past a certain point seemed to not change the amount of fuel going thru. OK to drive around town while figuring it out--but it's not the norm function for the truck

I took it to garage to have fuel pressure/flow checked---my suspicion is the tank fuel module is falling apart and that the fuel pick up tube is probably funky/ disintegrating/ busted off etc so that it does not stick into fuel and draw up the way it is supposed to anymore. This makes sense to me for the, went over a bump gauge went crazy stalled out starved for fuel with 1/2 tank on.\ and no visible fuel leak.

Garage says that yes tank module is toast flow bad. They also think my lift pump is bad.

This is my question---if my tank module is toast and not supplying correctly---- will that fink up the reading on the pressures from the lift pump? Is it possible it's just the tank module and the lift pump OK?

I'm surprized the mechanical lift pump would be bad (this is a 12v not 24)

1.) how do I know for sure? My thought was-- meh, tank unit toast, replace it and then double check the lift pump---it will either still show bad pressures or it will be ok ???

2.)what's best solution for the tank module--Liberty from Vulcan? If the one that it is in it is rebuildable/ rehabable fix it up with just the Vulcan draw straw "I" (one) Mine is a stock work truck with no mods other than Triton rubber lines. What about these on Ebay that are oEM http://www.ebay.com/itm/Dodge-Ram-D...Parts_Accessories&hash=item19f05913a1&vxp=mtr

3.) If I need a lift pump who to buy from- found this one from TBDiesel which is great price $89 but is it iffy quality manufactured ?http://www.thoroughbreddiesel.com/stock-replacement/dodge-94-98-fuel-transfer-pump.htm
Thanx much for the cont. advice!
 
#14 ·
Hey not to intrude on the thread but I too am having a similar problem with my 01 24v. It will "cut out" or buck and fuel gauge was on E for days then just started working again(not sure if its correct it not). Also my air bag light will dong off and on when it wants to...more commonly when it bucks. Could my in tank pump/sending unit be shorting out causing this crap? Thanks for any input.
 
#15 ·
Intrude fine by me ;) Yours is 24v so you have an electric lift pump, you will locate vicinity of fuel filter google image search will get you a diagram and likely real photos. Mine is all mechanical. I believe what is in the tank is pretty much the same though.

Like me, you probably need to determine if your tank unit is messed up and not drawing the fuel up into the fuel lines correctly all the time and/or your lift pump is acting up.

I have taken mine to a garage where they could check the fuel pressure/flow from tank and lift pump- because I wasn't equipped to do it myself.

The tank units over time plastic finks up, metal parts rust and fink up----the gauge on E is pretty common because the float rusts and stops moving correctly...or is fallen off banging oround yer tank.

My breakdown occured after hitting a big bump---gauge went haywire then to E as I was stalling out beside road with no leaks and 1/2 tank full. Garage has confirmed my tank unit output is bad. ----so I'd guess your tank unit is a bit iffy too based on your symptoms

I have never had a 24v--based on what I know though, you also want to be sure your electric lift pump is OK---because if it fails it can cause you more problems

Not sure about your airbag light---makes sense that momentary buck mini stalling is tripping something in the sensors
 
#16 ·
Yeah the one on the block I replaced...$300 later..OEM even :banghead:

That's why I'm thinking the one in the tank is shorting out or something. But not for sure. I guess I need to take it to ha e fuel pressure tested.

In another thread, the fellers said if I have one of the block then I don't have one in the tank? But how can you not have one in the tank? Gotta have a sending unit n stuff correct? And I have the plug/connected plugged in on top of the tank.
 
#17 · (Edited)
yes- you have to have a tank unit that sticks down into the fuel and like a "straw" permits it to get to your fuel lines --- your electric lift pump 24V(or mechanical cam driven pump 12V) generates the draw to pull the fuel from the tank----but that does you no good if the components sticking down into the fuel are disintegrating/busted/clogged whatever. The plug on the top of the tank module as far as I am aware just gives you your fuel gauge reading in the dash--based on the float in the tank attached to the module.

People that mod their rig--do things with Fass aftermarket fuel tank lift systems---which I have never dealt with--they are quite expensive

It is my understanding, that like most vehicles, the tank unit sooner or later will fail and it is a PITA. Some vehicles do have a electric pump of some sort inside the tank----this is viewed as a negative in general, same procedural PITA to replace and a more expensive part. If you do a google image search of Cummins 12v or 24v fuel module or send unit--- you will see the sorts of condition these things are in when people pull them from the tank.

The tank unit also has a screen filter on the bottom of it that get's gunked up. Also people recommend cleaning or deleting your fuel preheater --it has a screen that get's gunked up and is apparently a source of air leaks.

Getting the fuel and flow pressure from tank and lift pump was fairly painless for me via garage since I wasn't set up to do it myself just now.

I think it's worth a shot for you--- will either be a bingo or rule it out.
 
#18 ·
Let me post some accurate data here. There isn't a filter in the fuel tank. Gassers with in tank pumps have filters. The picture in Joe G's writeup is of a gasser module, otherwise they are the same. If the overvalved truck has an external fuel pump it will not have another one in the tank. The most common cause of inop fuel gauges is the arm on the sender loses contact with the variable resistor. I've never heard of one rusting up, if it did you would have more pressing problems to worry about. Modules do come apart. Somewhere around 600k miles I had to replace mine, but the only problem I had was an inop fuel gauge. If you don't have a hitch or an aux fuel tank in the bed, a lot of people find it easier to raise the bed to service the module instead of dropping the tank.
http://www.cumminsforum.com/forum/94-98-engine/58777-joe-gs-fuel-system-writeup.html
 
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#19 ·
yes- gotcha --It has that basket on the bottom that gets cruddy like the one at the fuel preheater

My garage suggests replacing the fuel OFV first--- because they think the symptoms are consistent with that. I think OK, I might as well it's easier to access and if all is better great...if not, I will access the tank. Yes, tilting the bed looks easier than dropping tank
 
#21 ·
yes- gotcha --It has that basket on the bottom that gets cruddy like the one at the fuel preheater
No, not correct. It is a basket, i.e., a container with an open top. Fuel sloshes over and around it as you drive. It doesn't get "cruddy like the one at the fuel preheater". The prefilter that is mounted below the fuel heater (which I hope you have removed and discarded by now) is a strainer and will clog up, but it takes a long time. I replace mine every 100k miles and it seldom has much in it. The basket is there to act as a reservoir when the tank gets low on fuel. It holds fuel while you are going up and down hills and is designed to keep your from starving the engine for a short period of time.

As far as a fuel pressure gauge goes, ditch the snubber idea. They are more trouble than they are worth. There are a few ways to monitor fuel pressure. I drilled and tapped the banjo bolt that connects the fuel line to the IP. I attached a flexible grease gun hose to it and on the other end I attached a needle valve with two female fitting. I screwed the sender for my Isspro gauge into the needle valve. With the valve closed I started the engine and cracked the valve open a red hair. No snubber needed and not enough shock to ruin the pressure sender.
 
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#20 ·
well this is annoying--- I left truck at garage yesterday with a run down on what had happened, what I did to get it running again, and that I wanted the fuel pressure checked because it seemed to be running OK around town but my pedal seems to do nothing from 1/2 way depressed to floor---like it changes nothing in the fuel supply zip zero.

Guys said yea yeah will do.

Well they did not do ;0(

They said they think I should try replacing OFV---which I agree OK easy enough..................but I did want to know what kind of fuel pressure was running too!

Will order the kit from Larry B's now do myself as well as new OFV
 
#22 ·
yes--- I like the description and pics from Illflem for hardware store do it yourself fuel pressure gauge in the check fuel pressure article
 
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