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Discussion Starter · #1 · (Edited)
I replaced the fuel pump assembly in our 1996 Voyager 2.4L about 4 years ago (200K miles OE pump died). I bought one from RockAuto with "Precise brand", which claimed high-quality (don't they all?). In the last 6 months, the fuel gage has become erratic when full to about half-tank. I don't mind the needle dropping down slightly, but it gives a warning chime each time, maybe every 5 seconds which drives you nuts. I finally pulled out the assembly to diagnose. Moving the float, I could reproduce it on the bench by rapping the top of the assembly. Note that the upper internal Metri-pak connector top was pushed off since the blue silicone weather-seal had swollen. I once tried using silicone vacuum tubing for the injector return hose in my 1985 M-B and it swelled up similarly after a week. Others have seen the same. Only Viton hose seem to last a long time in diesel or gasoline (used for fuel injector O-rings). That seal isn't needed since the mating side (part of housing) has no resilient seal, just the molded plastic which embeds the pins. That choice tells me the designers were clueless, plus the assembly wasn't tested in gasoline.

Another poster here said he fixed the same problem by bending the pins on the housing connector. I didn't get a photo, but I unplugged the inside connector and did the same. I had to pry it out while holding the release tab down. On the housing side, I bent the pins away from the wall a bit and twisted them slightly. On retesting, the level signal was stable as I tapped the housing. It varies from ~100 ohm full to ~1300 ohm empty. Note the housing connector routes one blue wire to ground, so just 3 wires on the van's connector (+12-pump, level, gnd for both pump return and signal-).

Re doing the job, you only need to remove the 2 strap bolts on the right side (passenger in U.S.) and tilt the tank down. The fuel assembly is secured with a large plastic nut which appears like something in the plumbing section of Home Depot. First time, I used a hammer and screwdriver to remove it, with tank off the van. That broke some of the plastic tabs off and was very tough. For re-assembly (and this pass), I bought the special tool shown ($17 used ebay), which made the job easy.

Can't tell yet if I fixed the erratic ding-ding. The engine wouldn't re-start, probably because I had run it down very close to empty and it wasn't quite level on the ramps and stands. I added 3 gal gas, but still wouldn't fire. I did get a good flow once from the test port while bypassing the fuel pump relay with a jumper wire, but as-left tonight no flow, even though drawing current to the pump. I hope I didn't burn up the pump while trying things. I'll check tomorrow after recharging the battery. The engine does run on starter fluid. If I do have to go back in and replace the fuel pump assembly, I might do as for my 2002 T&C. I found best price was an Airtex E7146M for only $61 on ebay. Listed for flex-fuel vans, I risked it would fit my T&C. Since can survive 85% ethanol, it should have better plastic (green). Fit fine and running for 6 months and fuel gage seems accurate. But, only fits 2001-2003. My 2002 has a different metal nut to secure it.

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Excellent post, the tank and above look very clean considering how old it is.

I have a 99 and I am considering doing a similar task as my fuel level gauge is messed up [ reads 1/8 tank when actually empty ].

A few questions.

Did you have to disconnect any lines to lower the tank? The fill line? I see a line running forward and some wires?
Do you have to drop it a few inches and reach in there to disconnect things before it can be lowered all the way?
Fuel lines brittle?
The fuel filter bolts to the tank, not the frame?

Looks so dang easy!
 

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Discussion Starter · #3 · (Edited)
Update. Finally got it started. Rather than just waste the battery and starter motor cranking, I bypassed the fuel pump relay to run it and vented air out the test port. That port has a Shraeder valve you can push in, just like your tires. On my 1996 2.4L, it is under the curving upper intake manifold. On my 2002 T&C 3.8L, it is under the air inlet duct after the filter. I was concerned I had overheated the fuel pump by running it too much when dry, even though the fuel level was high enough to run the engine when I parked it on ramps. After adding, 4 gal, it would flow out well then just dribble out the port. I think there was just a lot of air in the system since a lot of gas ran out of the fuel filter. I vented a lot of gas out the port (~1/2 gal), then cranked maybe 1 minute total before the engine would keep running. Even with venting, there was probably still air around the injectors. I had similar issues last time I replaced a fuel pump assembly. I had run the tank down to ~2 gal before starting the job this time.

To answer Drunken Elvis,

No rust in California. The undersides of vehicles look like when they left the factory. They don't salt the roads in the Sierras for environmental reasons, just sand which crunches to a white dust which coats cars, but washes off. This van spent its first 4 years in Atlanta, often parked outside under oak trees, but little rust from that time. The outside isn't purty after the brutal CA sun and a front hit on both the left and right (equaled out?), so the sheet-metal doesn't align perfectly, but good enough for my use as a utility van. I could always paint it a funky new color like grey-blue to look mod, but too many vehicles so need to thin the herd.

Yes, I needed to unplug the Metri-pak connector after lower the tank a bit. You can tell in the photo. Don't try this unless you have run the tank very low, or you won't be able to just let it hang under its own weight as I did. The blocks of wood were to support it while cranking on the plastic nut. First time I did it ~2016, the fuel pump had died. For some reason I couldn't get a tube all the way down to siphon gas into my other vehicle. I thought it was hitting a screen or such, but apparently just hung up on a shoulder of the fill tube. Anyway, I lowered it with ~15 gal in, which weighs ~80 lb and likes to slosh. Not fun.

If removing the fuel pump assembly alone, there are just the two nylon fuel tubes to disconnect, which go to the fuel filter atop the tank. If old, also change the fuel filter (~$15) so you could leave those attached until at the bench. A new filter comes with those tubes. The third nylon tube on the fuel filter goes to the vehicle. You don't need a special tool to release the fuel tubes. I used a little screwdriver to push each finger in, or pushed the collar in (forget), then wiggled it off. The O-rings inside are Viton which should last almost forever, so just re-use. The first time, the OE pump assembly plastic must have been brittle as one tube stub cracked off when removing the fuel tube. I was planning on perhaps just replacing the fuel pump (had a spare $20), but found a new assembly wasn't expensive. As stated, if you find a flex-fuel assembly as cheap or cheaper, as I did for my 2002, might jump on that since it likely more rugged plastic and "should fit" (did for me).

Note there is no return line from the engine since by 1996 an EPA mandate required "return-less" fuel systems (to not heat the gas). That is why the pressure regulator (shiny can) is on the assembly and just dribbles extra flow back into the tank. Originally, designers thought they must regulate pressure at the fuel rail, even adding an intake manifold pressure port to control the pressure drop. As an engineer who has designed controls that seems overkill since one can easily account for the normal pressure drop thru the system with an algebraic equation (other than changing drops in the filter) and Pman is already measured. Besides, that is just for a feed-forward estimate of needed injector duration which gets trimmed to the O2 sensor feedback anyway. So the EPA mandate was good and simplified the systems. Anybody who says today's cars are "too computerized to repair" has no clue and never dealt with carburetors or the even-worse 1980's early fuel and emission controls (electronic carburetors, air injection, Bosch Jetronic FI, ...).

I have read of leaking cracked nylon fuel tubes on other cars, and Autozone carries repair kits for those. On my vans, the nylon still appears fine and flexible. Perhaps they found better types of nylon by 1996.

If you do decide to remove the whole tank, you must remove the rubber fill hose and the vapor emissions nylon tubes on the outer side. Those are tougher to get to since not much room for hands. I removed the whole tank on my 2002 T&C because it has AWD so the driveshaft blocked the fuel pump assembly. Seemed easier and less risk than removing the driveshaft.
 
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