Fuel pump/relay issues...help! (1 Viewer)

[H8PVMNT]

I am seting up an '86 pickup that sat for a few years before I got it. Had everything running good after tune up and freshening up some leades and grounds.

Here's my problem: my wife took it to the gas station and it quit. We found out it wasn't getting fuel. I replaced the fuel filter, didn't help. I then took out the fuel pump and tested it. The fuel pump worked fine. We figured out that she kicked off the fuel/EFI main relay and it was rolling around on the floor . After plugging it back in it ran fine for one day.

I took it to the store today and it quit. We towed it home and found out it has no fuel again! I yanked up the fuel pump and here's the weird thing... It pumps with the key on and the truck starts up as long as I am holding it so the pump is towards the top of the tank, not touching anything. If any of the tubage or the pump touches the tank it quits pumping and dies. When I put it back down into the tank where it should be it also quits pumping and dies.

Here's another thing: the truck is throwing a two flash code which on an '86 is an airflow meter code! What the heck??

Could the fuel pump be shorting out on a baffle inside the tank when I put it back into the tank? Do they only work if they are suspended in there not touching anything?

Should I suspect the relay that got knocked out?

Am I missing something?

I'm really confused because the trouble is intermittent and we had it running the day before. Any advice on this issue is greatly appreciated!

Three beers to the guy who figures this out!!

 

[2ndGenToyotaFan]

Here's some good info for you:

http://www.4crawler.com/4x4/CheapTricks/index.shtml#FuelPump

I dont' have any other ideas for you though, also I don't drink, so if I win, you can just pass 'em along!

 

[H8PVMNT]

I think this trick might at least get me driving again, I'll try it tomorrow and let you know! Reading over that link and others it sounds like my real issue is either the main relay or my air flow meter. I like the switches the guy made for the diagnostic jumpers. Very good information, Thanks!

How about three cups of coffee?

 

[H8PVMNT]

The jumper wire didn't work! After clearing my codes and trying again I have also ruled out the airflow meter. I checked the relay that turns the fuel pump on and it works too. I am assuming the ECU is also working right because from the wiring diagram if it was screwed up the relay wouldn't turn on either. All wires look OK.

This might be as stupid as replacing the fuel pump! I just don't understand why it works out of the tank but not in it.

 

[2ndGenToyotaFan]

Maybe something in the pump motor is grounding out, and when you put it in the tank it's completing the circuit and killing it?.... No coffee either..... I'm really a boring guy.....

 

[WristPin]

the fuel pump has an internal short. the air flow meter is what switches the fuel pump on. and since the pump is shorted, the AFM is making that code show up.
replace the pump.

 

[2ndGenToyotaFan]

Hey, I may have been right!!!! I just guessed, but that counts right?

 

[WristPin]

Hey, I may have been right!!!! I just guessed, but that counts right?

yeah! thanks for the beer!

 

[H8PVMNT]

Thanks guys, I ordered a pump yesterday. We pretty much ruled out every other component, so hopefully it's the pump...

My buddy Don Wolff who has a Toyota boneyard says that the early EFI pumps have an internal preasure releif valve that acts like a fuse. It can be tripped when you have gunked up filters or crap in your tank. This truck did. You can't reset the pump though, unfortunately. I'll let you guys know what hapens.

 

[H8PVMNT]

It lives...

I am a jackass!! The new fuel pump didn't work.

$150 later... I was playing with all the wires with a wrench stuck in the airflow meter and the key on to see if the right amount of wiggling would make the fuel pump run. It ran when I wiggled the harness by the tank. As it turns out, there is a little clear resin bubble that protects the positive lead connection as it passes into the tank through that plate. There is a little riveted connector in there, supposedly protected from the elements. I ripped off the resin bubble ad found that the connector was really rusty and almost cracked through!

I made a new lead and ran it through a grommet with some silicone for a temporary fix untill I can go to Don Wolff's boneyard and get a new piece. Thanks for all the help. I learned everything I need to know about 22re fuel systems and AFMs.

I guess my wife gets the beers because she said it was probably somthing stupid like a wire! Go figure!!

Anyway, IT LIVES!! so now I can finish my suspension, exhaust and flatbed.

 

[2ndGenToyotaFan]

Hey! Glad you figured it out! So it would run while out of the tank because the wire would be pulled at a different angle?

Sounds like you have a smart wife!

 

[WristPin]

good you got it going. so does this mean we owe you a beer?