Big problem

[Kendal Coker]

My car will not cycle the fuel pump when I turn the key on. Here is what I have done

5 diferent computers
2 tfi moduls
ignition switch
Checked grounds, Firewall, under computer, on turbo, beside battery, two on core support, under hatch beside striker.
Brown Relay above computer
Several green relays
Jumped clutch switch
Jumped Crash switch on rear.
Coil has power
Spins over fine
I also checked all the fusible links


I think there is some kind of ground problem. If I ground out the small red wire on the relay the fuel pump will come on. Yellow wire is always hot.

Any help would be most appreciated. This car ran before I took it apart for restoration.

[MikeFleming]

Check to see if EEC pin 21 in the harness is connected to that small red wire on the FPR. Also make sure the other small wire on the FPR harness has +12V (with a testlight) when the ignition switch is on (sounds like it does, but check). Next check the fuel pump inertia switch - it interrupts the primary side circuit of the FPR.

The fuel pump relay harness goes left to the rear chassis wiring harness and runs fore/aft along the left side of the iniside of the outer chassis rail. When it gets forward to the kick panel area, there are connectors that mate with the drop-down pieces of the dash harness. Make sure all of those are connected.

The far right side of the dash harness has two or three connectors that connect to the EEC harness at the far right end of the dash, above the kick panel area. Check those also.

Sounds like one of those is either not connected or not making proper contact. You should nbe able to follow the same wire color(s) from EEC pin 21.

[Kendal Coker]

21 and 22 are hot with the key on. The fuel pump wires under the drivers side kick panel, yellow hot all the time, red and white hot with key on.

I jumped the inertia switch.

Buzzer under the dash goes off when I check the red and white wires.

[MikeFleming]

With power off and EEC disconnected - does EEC harness 21 connect to the coil wire on the FPR?

Pin 21 will appear "hot" when key is on. The EEC provides the ground to the circuit.

Are EEC grounds (20. 40. 60) good?

[Kendal Coker]

#20 is good, I get nothing from 40 and 60


When I turn on the premium switch it grouds 40 and 60 and the buzzer goes off.

I checked the battery ground wires that go to the body next to the battery and they are good.

[MikeFleming]

What year SVO and what EEC? Was it "repinned" from a PE to an LA3?

No idea why any buzzer would go off - afaik, no buzzers are not associated with the fuel pump relay circuit at all key buzzer, door buzzer and crank/overboost buzzer are all I can think of). Starter circuit, yes, but not fuel pump. No idea why switching the Regular/Premium switch would activate a buzzer as there is n buzzer [normally] associated with that circuit.

EEC 20, 40, and 60 are EEC grounds and connected to the EEC circuit card and EEC case. iirc 40 & 60 are connected together and connect to chassis just forward of the EEC 60-pin connector with a 7/8mm hex head reen bolt to the chassis behind the kick panel. Make sure that ground is connected. See pic highlites. I can't find a pic with the EEC ground wire eyelet bolted in place.

With the EEC removed, ignition key in On, ground EEC connector pin 21. That should engage the fuel pump(s). And no buzzers.

[Kendal Coker]

84 ZBA and TE computers. No pin change

Got the buzzing when I grounded 21. Buzzing is coming from the brown relay above the computer. I have tried 3 of them.

[MikeFleming]

Ahh, so it's not a real "buzzer" buzzer then.

Did the fuel pump(s) come on when grounding pin 21?

[Kendal Coker]

nope pumps did not come on.

they do work when I jump the green relay.

[MikeFleming]

Is there connectivity between EEC pin 21 and the wire on the relay you are jumping to engage the pumps?

[Kendal Coker]

Finally got it. Bad wire on the tfi. Bad grounds on 40 and 60. Went back to the first computer and tfi.

[MikeFleming]

Glad to hear it's running again!

[Kendal Coker]

Thanks for the help.

[Mike Croke]

Congrats on the fix. Those sorts of electrical gremlins are often aggravating and time consuming to chase down.