Fuel Pump not coming on- Help!

[getchasum]

Fuel pump is not coming on. I guess first I need to give history of current events. Car was running prior to replacing old fuel pump, timing chain install and a detail cleaning of the engine bay where I did have the engine compartment striped.

Here's what I got or found so far. The stock wiring harness is reading 8.4 volt at the plug prior to the plug going in the tank. When I turn the key on, it still has the 8.4 on center pin and .46 volt on one of the outside pins. The fuse under the dash is good, and if I try to jump power to the lead under the alt I get nothing ether. This was a brand new walbro 307.

What all could be wrong….keep in mind I did have all plugs in the engine compartment disconnect.
I was hoping to get her cranked today…….


Later & More testing results.....


The center red wire from the stock wiring harness that plugs into the purple wire of fuel pump has 8.40 volts. The tan wire w/ white stripe that plugs into the gray wire of the pump has 0.00 volts with key off or on. Fuse good and I swapped out a known good fuel pump relay with no change. I think the purple wire is for the sending which is reading correctly.

 

[milldorr]

I have the same problem. With the key on, I get the center wire ( fuel guage ) to show current. However the brown/white outer wire has no current. Change fuel pump relay and checked FP/inj fuse under the dash. I know that pump is good from a bench test.

Can anyone help?

 

[Boost231]

I have the same problem. With the key on, I get the center wire ( fuel guage ) to show current. However the brown/white outer wire has no current. Change fuel pump relay and checked FP/inj fuse under the dash. I know that pump is good from a bench test.

Can anyone help?

i had this problem once. just recently got it fixed. i didnt go as far as checking voltage but this is what happened to mine. so how the ecm fuel pump resistor got blown. i would pull the ecm and try it in another car and see if it turns on or not. if it doesnt its probley a problem in the ecm. send it to bob bailey and he will take care of you. once i got it back it still didnt prime put a new relay in it and bam all is well now.

 

[TurboBuRick]

What all could be wrong….keep in mind I did have all plugs in the engine compartment disconnect.

Fuel pump relay on the pass. side fender plugged in? If it is, check the signal from the ECM to the realy. Green and black wire. When the key is turned on that wire should come alive for a couple seconds and the relay should pull in. Note: It will only send a signal for a few seconds from inital key on. Then it shuts back off until the car is started.

 

[CHRIS W]

Ecm

I had the same problem twice. Sounds like the ECM to me. Try gyrhead, good price and no problems since.

 

[Boost231]

I had the same problem twice. Sounds like the ECM to me. Try gyrhead, good price and no problems since.

if its the ecm bob bailey can fix it.

 

[mec108]

My fuel pump relay makes a click sound when I turn the key to the on position? No pump or pressure? Is the relay bad? THANKS

 

[TurboBuRick]

If the relay clicks, it's getting a signal from the ecm. Did you check fuses?

 

[forzfed]

Mec108...If your relay is blown, you need a minimum oil pressure set point to bypass a blown relay and start the car.

 

[mec108]

Thanks

 

[cetme1]

Sounds exactly like the problem I am having. I am wondering if we all bought our pumps from the same place?

Mine was running before I purchased and installed my "new" pump.

I am into about my 2nd month trouble shooting, and I'm getting tired of it.

 

[TurboBuRick]

Don't take this the wrong way but if you guys knew how to use a test light or a multi-meter, you could figure it out in a mater of minuites. Without that, I don't know what to tell you.

Trouleshooting is the key, guessing will get nowhere.