So you know I just put in a new motor in my 92 B4C, the trans (manual) is not in the car yet.

I wanted to drain the fuel out of the tank, so after hooking up a hose I turned on the key and nothing, so I pulled the pump relay and put on the new one that I keep just in case.
It still would not come on, so I jumped the + wire to the gray wire, pump runs.

Now my question, looking at the wiring diagram it looks like the Dark Green wire is the one from the computer that primes the pump, I am not getting power from that one at all. I checked the plug on the computer (A 11 Dark Green With white strip) when I turn on the key no power, so I am thinking that it’s the computer.

Any ideas?

 

I checked the (A 11) dark green w/ white strip wire at the computer, when I turn on the key no power at this wire.
This is the wire according to the manual that sends power to the pump relay, so no power out then the computer must be bad.

The only other thing is the O2 sensor, driver side head temp sensor, VSS and the neutral safety switch are not plugged in.

 

try connecting the neutral safety switch and try again before you do anything drastic.

 

Thanks for the reply.

I will do that, if it does not help then I will swap out the computer out of the Z and see if that fixes it.

 

please keep in mind the computer does not send power to the relay, it provides a ground path for the relay. there should be two hot wires at the relay (with key on) one is switched with the ignition, the other should be hot at all times.

Good luck.

 

I fixed it and yes the computer does send power to the relay for 2 seconds, I checked this on my Z, unplugged the relay and using a voltmeter I get 12 volts on that wire for about 2 seconds. .


With the relay unplugged I checked the Green W/ white strip wire from the relay to A11 at the computer, no open or short showing, then with the connector unplugged and the relay plugged in I applied power to that wire and the fuel pump cam on.


I found out that the fuse for the ECM had fallen out, I had taken it out a long time ago and had not push it all the way in.

 

Ghost, on my car there is a fuse by the battery that provides power to BOTH the ECM and the fuel pump.

I know this for sure since I blew this fuse last night during my fuel pump swap.

My fuse is located behind the passenger side headlights.
On Mr_Dude's car it is mounted on the fender wall by the battery.

See if it's blown. 20 amp fuse if I remember right . . .

 

Thanks Ragtop I fixed it (go see my post on the club board) and all is well now.

I got the system up to pressure and bleed the air out and found no leaks, the parts from Spohn should be here Wednesday and the car is ready for the tranny.

I hope to start it up next weekend.