Hello all, and Happy New Year.

My '00 DD 4x4 w/4.7L is exhibiting an issue which I believe is related to fuel.

I had first thought that changing the fuel filter might be a low-cost and easy start to the troubleshooting/fixing process. In doing some early research, however, it appears that the idea of changing the fuel filters on this thing is one left to professionals, or at least a dyed-in-the-wool hobbyist, of which I am neither.

Specifically, the FSM indicates that "[b]oth fuel filters (at bottom of fuel pump module and within fuel pressure regulator) are designed for extended service. They do not require normal scheduled maintenance. Filters should only be replaced if a diagnostic procedure indicates to do so."

My truck has just over 290K and so I have to wonder if the filters were designed to last that long. Even so, given the location of the filters, such a replacement job is not for the faint of heart.

Anyway, here is the issue I'm having: when climbing even a modestly steep incline, the truck bucks and balks...as if there is a fuel shortage. When traveling on level surfaces and declines, no such activity occurs. Understand that the truck is carrying nothing other than it's own weight: no extra-heavy passengers, no trailer and nothing in the bed. Just little 'ol me. Also, the fuel tank is nowhere near EMPTY.

So, with the DIY fuel filter replacement out of the question, I figure that my DIY options are: clean/replace fuel injectors OR clean/replace spark plugs.

(I wouldn't necessarily consider replacing fuel injectors as a DIY job, still....)

I'd be grateful for others' thoughts as to what might be both the issue and a remedy.

Thank you!

 

What makes you think it's a filtration issue and not just a weak fuel pump? I believe the filter is embedded in the plastic body of the pump and you'd have to break it apart to take out. Check your fuel pressure. Could even be a transmission issue.

 

My thought was that if it was a fuel issue, replacing the filter might be a relatively easy and inexpensive fix. I was going for quick, painless and low-cost troubleshooting related to fuel.

So yeah...I actually have no idea what the issue is, hence my question.

Thanks.

 

The filter is part of the fuel pump.. Far easier just to replace the whole fuel pump.. Should be a filter sock on the pickup in the tank than another screen in the pump itself... I high doubt you have 300k on the factory fuel pump they are usually around a 100-150k item.. I would check to see if you are getting enough fuel psi.. Any check engine lights on?

 

Hello, and thank you for your comments.

Can you tell me how I would check "fuel psi"? I'm guessing I'd have to take it to a mechanic. Also, I have had the "Check Engine" light come on several times. Once was for a leak in the PS system, and then another time for a battery that was dead.

Other than that, no "Check Engine" light on.

I will note that I put in one can of SeaFoam last week. This seems to have helped, altnough not completely eliminated the problem.

Thanks again.

 

Yes or if you go buy the gauge, they arent hard to check.. A private mechanic would prob do it for free vs the dealer who would want to charge you.

 

Ok, DRG85. Thanks.

 

You can also rent the gauge through the Loan-A-Tool program at some auto parts stores (AutoZone, for instance). It's easy enough to use - find the proper adapters in the kit, connect the gauge to the Schrader valve on the fuel rail (it should have a black cap on it, but looks like the valves on the tires ... for good reason!), and have someone else start the truck, listening for you to holler "CUT IT!" if you didn't get it on right or if it has a leak (what, you're going to leave fuel spraying at 40+ PSI around your engine bay? *grins* ) AutoZone can also print out what the pressure SHOULD be.

Does the incidence happen more or less with a full tank, a 1/2 tank, or a 1/4 tank?

To replace the fuel pump assembly isn't that hard, but most find it easier to pull the bed off (six or eight bolts around to the frame, a connector for the lights, four at the filler, and maybe one to a ground wire middle front, all but the filler from underneath) to gain access. Also, if you do the fuel pump, a) AutoZone can also print out the instructions, b) AllDataDIY and eautorepair.net (Mitchell1 for DIYers) have very good manuals on line, c) Ebay typically has the factory service manual available for not a lot, d) Bishko publishing also has the manuals, and was the publishing firm used by Chrysler/Daimler/FCA for the service manuals. I'd do at least one of them, and ignore the Haynes and Chilton manuals. (The latter two I find like reading about kissing someone as opposed to the four earlier ones being a few minutes of liplock with your sweetie ... )

But yes. Test fuel pressure. The manual will state what it's supposed to be. Low pressure can cause all kinds of strange performance issues.

Then, using the procedure in the manual, check fuel FLOW (i.e., how long to dump a gallon into a 5 gallon bucket, for instance.) If THAT'S off you'll have problems.

I'm about to bet that it doesn't happen on a full tank, and that the problem is that there's a small crack in the lower hose that exposes going up a hill, but is covered when the truck is level. Which would STILL call for a new fuel pump assembly, so the distinction is rather small *grins*

Oh. A few warnings.

1) If you tackle this yourself, take copious pictures disassembling and reassembling. Be SURE that all parts are turned the same way (for instance, the fuel pump assembly may fit in the tank two or three ways, but only one will allow the fuel gauge to work properl.)

2) Gasoline is flammable. And in the proper mixture with air, explosive. Do NOT allow open flames around that tank while you're doing the job.

3) Clean everything off before you remove the fuel pump from the tank. You don't want to try to pump a slurry through a new fuel pump.

4) Don't cheap out! That old Mopar pump lasted, what, 290K miles? When my Malibu was having fits, I went through Airtex pumps every 15,000 to 20,000 miles ... and until I went back to Delco parts, was a common occurance. My Delco lasted over 75,000 miles and was still going strong when the surge tank blew and the motor overheated, warped, and basically killed the car at 330,000+ miles. (!!!) There are other replacements, but buying on price only is not a smart move IMO. (Now, if you find the Mopar pump for 50% less at, say, RockAuto from the dealer price, no problem doing THAT. Just don't buy a "Honest John's Fuel Pump and Pizza Emporium!" 12.95 special ... )

5) Unfortunately, you have a quad cab. Forget what I said about removing the bed ... you'll have to drop the tank. At that point, I'll have to say take it to a shop, open your wallet, smile, and let the nice mechanic keep removing money until s/he's happy. (Pournelle's Law as applied to any work being done.) Or buy/rent/borrow a transmission jack, and with the mileage, I'd pick up some new tank straps before dropping the tank (they tend to rust and break during removal on older trucks - and 290Kmiles is older!)

RwP

 

RalphP...lots of great information. Thanks for taking the time to post this for me.

One of my favorite adages is from Dirty Harry: "A man's got to know his limitations."

I'd like to think I am that man...lol.

I mean, this does not sound like a DIY job for me. So, yeah...I'll probably be taking the truck to a mechanic as per your suggestion.

"Does the incidence happen more or less with a full tank, a 1/2 tank, or a 1/4 tank?"

Great question. I hadn't thought of that but I'll make a note to pay attention to the fuel level when it does in the future. Thanks.

"I'd pick up some new tank straps before dropping the tank (they tend to rust and break during removal on older trucks - and 290Kmiles is older!)"

Another good point. So noted....

"Don't cheap out!"

Indeed! The mechanic gets paid the same amount regardless of the pump's quality. So we'll be going with an OEM or better.

 

Heh. I had the infamous "Runs, stops, runs, stops" problem of a dying fuel pump about a year and a half ago.

Found out that it was easier (1st gen 8' bed standard cab) to pull the bed for me.

And the hoses were failing, along with the pump.

So natch new hoses, pump, rebuilt the fuel level sending unit, and replaced the hoses outside the tank.

Got lucky on the in-tank hoses, though - a local hose shop had some off-fall that was about 6" long on one side, 7" on the other size, and .. pulled them out of the trash can and gave them to me. Can't beat that, especially since a foot is typically $22 or so at the parts houses (since both the OUTER layer and the INNER layer have to be able to stand being immersed in fuel, including ethanol ... try that with your typical fuel injector hose, and see what happens to the outer layer.)

RwP