darren roar

iTrader: (1)

The problem I'm having is I can't hear my fuel pump turn on. Can you fire a engine without having the ecu reflashed? I'm using a walbro 255. I used the pinout chart from lt1swap also. This is my 1st efi swap. I'm not a wiring guru.

gagliano7

You should hear it run for 2 seconds with the key on then it will stop until you start it. DO you have a fuel pressure gauge? Put one on the rail and turn key to see if you get pressure. If you push the pin in on the schrader valve fuel should squirt out but be careful. You will still need to get vats turned off on your ecu before it will run.

JetMech442

iTrader: (1)

lolz, gagliaSo you have the ECM "fuel pump out" pin signal a 12V relay? The Walbro is a lot quieter than the Holly "Red" pump..a lot quieter. (just assuming you had one of those as they are muscle car favorites).

It only cycles for 2 seconds at key on. you could put a voltmeter on the output of the relay while you key on to make sure the ecm is triggering the relay properly.

If the ECU has not been reflashed though, you might be running into VATS(Vehicle Anti Theft System). If the ECM doesn't see the PWM signal from the VATS then it won't turn on the fuel pump or injectors. Now that I think about it, this is probly your issue if you havn't disabled VATS.

Hope these thoughts help.

EDIT: lolz, I've been writing a response in between meetings -looks like gagliano beat me to it.

garys 68

iTrader: (1)

Just to be sure, you know the fuel pump ecu pinout provides 12V to the relay, not ground like the other functions.

darren roar

iTrader: (1)

Thanks guys. I put 12v from another battery on it. The fuel pump works. The wire from the ecu needs to be on terminal 30 on the relay, correct?

-Siggi-

No.

30 is fused power
87 goes to the pump
86 is the wire from pcm
85 ground