92 chevy farm truck 4.3 keeps stalling

[Jhn]

92 k2500 4.3 v6 5 speed. It has electric fuel pump and tbi. It keeps stalling due to running out of gas. If I shut it off when it's about to stall and let it coast for a minute and then start it again it is good for about a minute and then starts running out of gas again. I put a new fuel pump on early in spring, and checked the fuel filter and it blew thru easy. (It seems they usually don't get blocked with fine screen in tank) it was working ok for a few months until this past week. I took air filter off which made no difference. I don't know if it could be something with tbi and there isn't another filter on the tbi fittings like a carburetor has is there? I'm wondering if I try hard wiring the fuel pump when it starts sputtering if it's possible it's not getting enough current.

 

[omahagreg]

on my 96 Silverado I was having stalling issues. It had 2 positive battery cables directly connected to the battery. It had corroded and would sometimes, sometimes not make connection. The second cable went directly to the fuse/relay box on the fender liner. Replaced the battery bolt and the inner cable-no more issues

 

[Dennis Minn]

JHN,

I had a 4.3 that was troublesome. Perhaps, like in my truck, the EGR needed to be blocked off. Massive vacuum leak. Leave the EGR plugged in to prevent the check engine light.

Hope this may be of use.

D.

 

[Steve@Advance]

Trying to remember how the pump is powered. There is an oil pressure switch and a relay involved.

I'm wondering if the oil pressure switch (not the gauge sending unit) is failing. If the diaphragm is leaking internally, it will false sense low pressure. Then when shut off the switch will reset and repeat.

There is also a relay, on the firewall under the plastic cover?

 

[504]

Check to see if it will run without the gas cap, a plugged vent on the tank could cause your problem.

 

[wore out]

(quoted from post at 09:32:31 07/30/22) Trying to remember how the pump is powered. There is an oil pressure switch and a relay involved.

I'm wondering if the oil pressure switch (not the gauge sending unit) is failing. If the diaphragm is leaking internally, it will false sense low pressure. Then when shut off the switch will reset and repeat.

There is also a relay, on the firewall under the plastic cover?

The 'puter controls the fuel pump relay.

The oil pressure switch is a backup system.

For the pump not to run BOTH the primary control from the 'puter AND the oil pressure switch backup have to fail.

This could be solved very easily, monitor the fuel pump voltage and current at the relay, and the fuel pressure.

There is no test port, an adapter is necessary to connect a gauge.

Personally, the first thing I'd do is replace the fuel filter. I can't imagine being at this point and NOT having changed the fuel filter!

The statement ''It seems they usually don't get blocked with fine screen in tank)'' is pure bull puckey.

Note that with key ''OFF'' or 5 seconds after key is switched ''ON'' you can power fuel pump by applying battery voltage to ALDL pin ''G''.

While doing that you should be able to hear the fuel pump start and continue to run as long as power is applied to the test pin.

 

[gab]

A lot of those trucks from that time frame would split the short hose above the fuel pump, my 90 GMC included. The only time that truck died was when I slowed up for my mailbox. It restarted just long enough for me to back up a few feet and coast it into the driveway.
I think pump pressure is about thirteen to fifteen pounds, I got a gauge and the tool for the gas line port.

 

[4play]

What is the oil pressure gauge indicating?
One symptom of the oil pressure switch providing FP power is a long crank to start, because the engine has to build oil pressure to power the pump. Another symptom might be what you are explaining. At hot idle the oil pressure might be dropping just enough to open/close the contracts powering the pump. If this confirms what is wrong, your engine might have really low oil pressure at idle, or hopefully the oil pressure switch is failing too since I think it only takes 4-7 psi to power the pump.

If it's still there, there's a plastic cover on the pass firewall (above valve cover). Under the cover is the fuel pump relay. There is also a single wire connector right at the fuel pump relay harness that you can supply 12v for fuel pump testing, I think the wire is red. That bus bar to the left of the relay is a good power source for a jumper wire.