Confirm my bad fuel pump diagnosis (1 Viewer)

[Eicca]

1992 3FE, 218k miles. New battery. Recent spark plugs, wires, cap and rotor. Cranks strong. Runs fine for a good while, but will eventually start stumbling and stall out completely. Hitting the gas does nothing to help. When it does stall out and I try to crank it again, it sounds like it almost wants to catch but it won't quite fire. During this time I also get a strong partially burned fuel smell.

When it stalls out, the dashboard reverts to the ready state and the check engine light is on. No trouble codes.

This occurs completely randomly. Sometimes it may take a while before it'll fire up again, or sometimes only a minute or so. This leads me to believe it is an electrical issue and most likely the (original) fuel pump. Is this sound reasoning?

If I spray starter fluid in it, I can get it to start and limp it along by continuously giving it small squirts, and eventually it'll start running on its own again. Because it runs on starter fluid this leads me to believe the ignition system is still delivering a proper spark.

I'm limited on time to really dig into this, so hopefully there's nothing else it could feasibly be.

Your input is appreciated before I go order a new fuel pump.

 

[SUMMIT CRUISERS]

Change the fuel sock/ strainer first. Fuel pumps "typically" work or don't work. I've experienced the exact symptoms and it ended up being the strainer. I would also change the fuel filter (passenger side frame rail) at the same time.

 

[Eicca]

Change the fuel sock/ strainer first. Fuel pumps "typically" work or don't work. I've experienced the exact symptoms and it ended up being the strainer. I would also change the fuel filter (passenger side frame rail) at the same time.

The sock on the pump, right? Might as well change the pump too while it’s apart.

 

[flintknapper]

The sock on the pump, right? Might as well change the pump too while it’s apart.

Yes, if you remove the pump (and it appears to be the original) just replace it. No sense going that deep into the project and not replace the pump UNLESS it has been replaced previously. A decent pump and replacement 'sock' are not expensive.

 

[baldilocks]

If you buy a garbage pump then you might as well leave the original in there. Original pumps can go a very long time.

 

[gummycarbs]

Every time I've seen a fuel pump fail (only twice, I think), they've blown fuses. Larger and larger fuses until the thing just won't turn anymore. (not that I advocate running larger than specified fuses, but do as I say not as I do)

The only way to know for sure is to put a fuel pressure regulator on the fuel rail (at the very back, under the EGR area) and watch the pressure when the problem occurs. It's kind of a PITA, but I think it's a lot easier to get to if you unbolt the engine wiring harness from the firewall in order to get some slack in there.

On the other hand, it's pretty darn easy to replace the fuel pumps on these rigs. Just make sure to buy a reputable one, I guess... And you might replace the check valve while you're in there (you have to drop the tank a couple inches, I managed it pretty easily).

 

[SUMMIT CRUISERS]

The sock on the pump, right? Might as well change the pump too while it’s apart.

Yes, sock on pump. If you are on a limited budget or would like to spend the $ elsewhere, that should fix your issue. If you want to change the pump, that's up to you. The whole process of removing and reinstalling the 2nd row seats, carpet, access panel, fuel pump assembly shouldn't take more than an hour. Personally I would buy OEM on the sock (and retainer) or find one exactly the same. Some of the aftermarket one's have the plastic 90 that extends too long which allows your pump assembly not too bolt up right.

 

[Eicca]

RockAuto has a Denso pump for $80. I also remember my mom’s UZJ100 acting similar when that fuel pump died. No blowing of fuses, just stumbling and dying.

 

[inkpot]

Does sound like a fuel issue. I would start with a new fuel filter. Cheap an easy. Then go for a new pump and socket second if the filter doesn't solve it.

 

[ajax1]

I bought the denso from rock auto with sock, plug in play, you might want some new copper crush washer where the line bolts in

 

[Malleus]

The FSM says (I wouldn't have thought these would be first, but what do I know?):

In addition to the suggestions already made, since (I agree) it sounds like a fuel problem, you might want to check the fuel pressure regulator, if the filters don't do the trick. It's cheaper than the pump and much easier to get to.

 

[Malleus]

Here's the EFI section of the FSM:
1992 1FZ-F, 1FZ-FE engine manual (RM283E) - EFI section.pdf