Red Dodge Diary

Have you ever had a vehicle that seemed to “eat fuel pumps”?  Maybe it’s just me, but in my opinion, in the life of a car, you shouldn’t have to replace a fuel pump more than twice unless you plan on keeping your car until it reaches Antique status.  My story today is about a 1998 GMC Jimmy, V-6 4.3 liter.  We bought this one brand new, and for the most part I liked it, but was happy not to be the everyday driver of it.  If you happened to have read the article on my 1989 GMC Safari mini van, you’ll notice these two vehicles share the same engine. I like that V-6.

So the story here is that at roughly 75,000 miles, the Jimmy had it’s first fuel pump failure.  It had been driven to a grocery store, parked, and when shopping was finished and it came time to go home, it absolutely refused to start.  I had it towed to the house.  At this time, I would like you, the reader, to troubleshoot the problem and think what it might be.  If you said “fuel pump”, you would be correct! Good job. Did the article title help in your diagnosis?

I’d like to say at this point that changing the fuel pump on this vehicle is not fun in any stretch of the imagination. Sure the professionals have all kinds of lifts, fancy tools and so forth, and it’s not such a big deal, but for folks like me at home with only a decent tool set and a slab of concrete to work off of, it’s a lot more challenging. Naturally the pump had to die with a nearly full tank of gas. You do remember the fuel pump is inside the gas tank, right?  Great.  I’ll tell you right now, if they had designed a removable hatch plate into the back deck of this car located above the fuel pump area, it would save thousands of lives. Ok, not so much lifesaving, but it would have made life worth living again for ease of access.

The Gas Tank

“Bombs Away!”  Time to drop the tank to get to our dead fuel pump.  After fashioning a gas tank removal jack out of my regular hydraulic floor jack by fabricating a wooden platform and attaching to the jack, I positioned the jack under the tank to support it while I removed the straps holding it in, and the fuel tank filler and vent tubes. Once the filler and vent lines were disconnected, I needed to siphon out a lot of gas to keep it from running out of the disconnected filler neck. I lowered the jack sufficiently to view the fuel lines attached to the top of the tank. I had to reach through the wheel well with the wheel removed to even reach these lines. They have to be disconnected to get the tank out of there, and where the lines connect to the tank you will find quick connect fittings which take a little finessing to get disconnected unless you have the special little tool in your box for them.

Fuel line disconnect tool

Basically there is a couple of tabs on each fitting that when pressed, you can work the coupling apart. Be ready for fuel spillage. Finally! I’ve got those lines disconnected, and the electrical plug too.  Everything looks free and clear, now I can lower my tank and roll it out from under the Jimmy.  Lunch time!

A fried bologna sandwich and an ice cold Pepsi later,  the tank is now on the ground and I can remove the pump module. The module contains the pump itself, the fuel level sender, and all the tubes, wires and fittings needed to make it all work.

The Fuel Pump Module

There is a locking ring that has to be rotated and removed in order to remove the module.  First I cleaned off all the accumulated dirt and crud around it. I don’t want crap falling into the tank.  I had already been to the auto parts store and bought the new pump module, which rang up somewhere around $250.  It was sometime later on that I discovered I could have just purchased the pump itself and changed that for around $60. I really didn’t need the new housing, fuel level sender and all that jazz. It’s more work to change out the pump only because you have to remove and replace it within the module. To save cash, I’m changing the pump itself from now on.

Now I have removed the module, and it’s time to inspect and clean the tank interior. You’d hate to drop a new unit in there with a load of junk waiting to ruin it. From this point in the story, let’s accelerate things a little. The new module is in, the tank has been reinstalled, basically a reverse procedure from the removal. A new fuel filter was installed, which thankfully, was very easy. I elected to do that since I had opened fuel lines, and who knows what the dead pump had shoved into the filter before it died. Everything is put back together, I turned the key to “on” (not start) and listened for the whirring of the fuel pump. Yep, there it is!  At this time I did an under car leak check to make sure all those fittings and hose clamps were good.  Turned the key to “start”, and off we go. On the road again.
Alas, the Eye of Sauron is upon us…

And it came to pass, that the joy of lasting fuel pressure was not to last. I don’t remember now how many miles were covered by the second fuel pump, but it was seemingly a short span, or perhaps it was the difficulty and frustration experienced during the first pump change that caused it to feel like I had recently finished that job. It probably wasn’t more than 16 months or so.  But it’s DEAD! Number two is history. Finished. Toast.

After replacing the pump once again, with pretty much the same level of fun and excitement experienced during the first change, the itty bitty nano gears in my brain began to turn. I wanted to know, “what caused these pumps to fail?”  With pump number three doing it’s job, I now had some spare time to investigate.

‘Twas not made from shards of the Narsil Sword!

I will share my failure analysis of these pumps in the next article…