1991 Isuzu Pickup Won't Start

It's in the fuse/relay box in the engine bay on the passenger side. It is the one that is surrounded by the other relays

Don't most vehicles have some sort of safety switch to shut off the fuel in case of an accident? Maybe in the truck of a car--I don't know about a PU.

maybe the fuel filter

One posibility is that debris in the fuel tank could be obstructing the flow. Remove the fuel filler cap to vent the tank. Enter the fuel line as close as you can to the tank, apply compressed air to blow back into the tank. Close the fuel line, reinstall the cap, go for a ride. If it runs better you now know that you need to drop the tank and have it cleaned by a professional. ( I had this problem on one of my boats )

bring it to a garage or a scrap yard.

If the previous owner reported that he had to bear down on the pedal to keep it running, that sounds a lot like the fuel filter needs to be replaced. Of course it might also be the fuel pump, so you might try running a jumper wire from the battery to the fuel pump to see if that will pump fuel down the line.

Usually, the fuel pump relay either works to activate the pump or it doesn't. So, it is a go/no-go situation, not dependent on the position of the accelerator pedal.

Please post back when you have it figured out to let us know what it is. Thanks.

OK the man I got the truck from told me and has the rceits to show he had the tank removed, a new fuel pump put in and the gas lines blown out and the tank cleaned. I traced the wires for the fuel pump and thought I was not getting current to the pump, But the key has to be in the crank possition to get current to the pump. I took the line off going to the diofram by the fuel rail and had a helper hold it in crank possition to make the pump work But no fuel came out. I put 5 gal of fuel in and still nothing. The fuel pump makes a wineing sound so I assume it is working. I can't figure out what is the matter. If you take the air cleaner off and shoot starting fluid into it the truck runs as long as you keep spraying the starter fluid and dies when you stop.

Ok... and you replaced the fuel filter?

yes the mecanic said he replaced the filter,fuel pump and cleaned the tank

Something is not adding up. I've had mechanics tell me they did work on my vehicles that was later proven they did not do. I won a law suit against one because he didn't check the fluid level in a transmission that went dry after driving 1k miles. He had charged me for an oil change and lube just days before we took off for the holidays. That cost him (his insurance company) the $1,000 to fix the tranny, plus his lawyer's fee.

Can you unhook the filter from the fuel line and activate the pump? The mechanic may not have changed the filter or he may have put in a bad pump. You should be able to hear the pump for a couple of seconds on initial turn of the key, but it probably should not be whining, as you describe.

I have a electric fuel pump I took off one of my bikes that I know works. I am going to hook it up and see if I can get fuel through the lines, If not I will pull the tank myself and check everything from the tank forward again, the fuel pump is in the tank so if I can't find anything wrong from the tank to the fuel rail it has to be a collapsed line or one kinked I would think.

Did you find the problem to your fuel delivery issue yet?

I have the same problem with my son's 91 Isuzu pickup. Have replaced the fuel filter, but have not yet replaced the fuel pump. It still won't start except with starter fluid spray. Once started, it will idle for about 45 seconds, then dies.

I have heard that this problem can be the fuel pump relay or the alternator in addition to the fuel pump. Have you tried replacing either one?