1990 4Runner V6 Fuel Pump Problem

[Currituck22]

The fuel pump will run when you put the key in the start position, but when returned to the run position, the fuel pump quits running. I can start the engine but it obviously quits running because the fuel pump quits running. If I reach under the hood and flick the throttle by hand rapidly, I can keep the engine running as if the fuel pump cycles with a flick of the throttle, but if I hold the throttle open, it stalls. If I let the throttle close, it stalls. I have checked the main EFI relay, and the Citcuit opening relay behind the passenger kick panel and they are both working as per the shop manual. I have not yet checked the air flow meter which is also in that circuit according to my manual, but I can't figure out why the fuel pump will not keep running. Anyone have any sudgestions?

Thanks

 

[blck90sr5]

This sounds like a problem that i had after an engine swap and to find out it was because the mass air flow was disconnected. The fuel pump kicks on to pressure the system when you start the vechile the computer tells it no air so it does not send any fuel. hope this helps

 

[n8buddy]

maybe the problem is in the air flow meter. When air is flowing through the meter it closes a contact which turns on the fuel pump. so if the contact is shot it could not operate the fuel pump properly. just an idea.

 

[Currituck22]

Thanks Guys

That is what I'm going to try. I've pulled the top of the air cleaner and will go through the AFS today. May have to take a ride to the Pick and Pull.

Thanks

 

[Currituck22]

Update stupid mistake

The air flow meter was not working because there was no air flowing through it. I bought this 4R for 500 bucks and it has had a tough life. The last owner had pulled all the air intake hoses off between the air filter and the intake manifold. When they put it back on they mashed and deformed the bottom part of the hose that fits over the bottom portion of the air cleaner. As a result, the air was comming in through that opening and not through the air cleaner. The air flow gate was not moving at all and the contacts in the air flow meter were not closing. Got the hose back on the bottom and the engine started up and ran.

The guy that owned it before me could not figure this out so they cut the fuel pump power wire under the back of the vehicle and ran a piece of speaker wire through a hole they punched in the fire wall, down the frame, and tied it to a body stiffener under the rear end. They then twisted the wires together and wrapped duct tape around it. They jammed the other end into the fuse box at a fuse that ran when the key was on. SCARY STUFF. I have also had the started re-built and replaced the start relay. They had run an 18awg wire straight from the battery positive post, through a ragged hole in the fire wall to a push button, then back through the same hole down to the starter solenoid wire. Again using the twist and duct tape method of connection. They had no fuses in this lash up at all which causes me to wonder how the $ Runner never burned to the ground.

Still a lot to do, but I only paid $500.00 for it so for now I'm pleased to have it running.

Thanks for the help and advice.