Ref: 1989 4Runner 3.0

Wont run unless I am giving it gas. After a while, I guess it floods and then dies.
I think I read that if you turn the key to the on position, with the gas tank cover off, you should hear the fuel pump humming / running for a few seconds.
I can't hear mine running at all when I do this.

So, I jumped Fp and B+ and then turned the key to the on position, and I could hear the fuel pump running.

Does this indicate my new fuel pump is bad?

Thanks

 

If it runs with the test connector shorted together, the fuel pump is good.

Get a wiring diagram and trace all the wiring for the fuel pump circuit to see what's not connecting.

 

Does the Fp B+ jump run on a separate wire? My thinking is that if the pump runs on the jumper, then the wires are good.

 

Jumpering FP to B+ bypasses the Circuit Opening Relay (COR). I don't know what you mean by "run on a separate wire."

Here's everything I know about the fuel pump circuit: https://www.yotatech.com/forums/f116...-quits-312747/

 

I used the link within the link sent about the Fuel Pump Circuit and performed a continuity test on the COR.
https://web.archive.org/web/20141114...96circuito.pdf
The Circuit Opening Relay Inspection diagram shows there should be:

Continuity btwn STA and E1
Continuity btwn +B and FC
No Continuity btwn +B and FP

My test revealed:
Continuity btwn STA and E1
No Continuity btwn +B and FC
No Continuity btwn +B and FP

Since I didn't have continuity with +B and FC, I thought the easy fix was to buy a new COR.
However the new COR does not have continuity with +B and FC. I am guessing this diagram is incorrect. Or I did something wrong.
I used 2 different testers with the same results.

 

If you're certain you got the right pins when you tested B+ to Fc, and the new COR is open between those two pins, you got a bad one. A glance at the schematic linked shows that clearly.
A coil, essentially an inductor, should read a short. Some of the bigger ones may start out showing open, and then the ohms drop as the field builds out around the inductor, but that's some pretty big inductors. The coils of relays don't normally do that. All that to say relay coils should read a short. Since B+ to Fc is reading through a relay coil, it should read a short. "New" or not, if that is the reading you got, it's indicating a bad coil.
It happens with mass production. I'd take it back, and check any others they give you to replace it. Right there at the parts counter, when they hand it to you. It only takes a few seconds, and can prevent this sort of frustration. Bring a print-out of the schematic with you, so you can show the parts guy just exactly what it is you're checking.

Good luck!
Pat☺

 

If you had no continuity FC to B+, then you would have "runs for a few seconds and quits." (The fuel pump would shut off as soon as you released the key from STArt.) You would not be able to keep it running by giving it the gas or otherwise.

Unless your "after a while" is only 1-3 seconds, I would expect the COR to be okay and there is a problem with your test procedure.

 

Thanks for the help!
I was able to get a third tester; better quality than the other two I used.
I was able to get continuity on the COR in the right places.
So, now I have two good COR's - oh well.

Will start over with the link provided for the Fuel Pump Circuit using the new tester and see if I missed something.

 

Step one: jumper FP to B+ and try to run it. Is it the same? Then your problem is not in the COR-VAF circuit.

Step two: replace the fuel return line from the FPR with a 6mm (1/4") line to a suitable container. Start the pump. There is no spec on this, but I get about 1/2 liter/min. This doesn't directly test the fuel pressure (that's set by the FPR), but it shows that the pump is pumping enough (if the FPR is approximately correct).

Step three (only if you pass the first two): check fuel pressure. For this you'll need a gauge, and some way to plumb it into the fuel rail. DO NOT think you can test fuel pressure by "cracking" a connection to look for a spray of fuel. Besides not telling you anything, every time one of those connections is loosened you must replace the two crush washers. One time use. And do you really want to be the guy explaining how he managed to burn up his truck, garage, and tools?