All,
I just rebuilt my '93 960 engine after the timing belt broke. When I first tried to start the engine the fuel pump kicked in, but the fuel rail leaked. I turned the key off and reset the o-rings on the fuel rail. When I tried to start the engine the second time, the fuel pump wouldn't kick in. I thought it might be the relay, so I jumped the pins (as stated in the FAQ) and the fuel pump turned on. After getting a new relay from eEuroparts, I put it in and alas, the fuel pump didn't turn on. What else should I look at? It's not the fuel pump and it's not the relay.

Thanks,
Steve

Timing belt set up correctly? Got spark?



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David Hunter

Hey David,
The timing belt is setup correctly and I've got spark. The problem is the fuel pump doesn't kick in when the key is turned on, but the fuel pump operates when its relay is jumpered between pins 30 and 87/2. Looking at the FAQ, it looks like it could be a bad ECU fuel pump control circuit.

How much do these run? Are these something I can pickup from a chop-shop?

Thanks,
Steve

Are the injectors working, do you feel them clicking? The fuel pump should only run for about 1-2 seconds once the key is turn to on, then it shuts off and goes back on during the cranking stage. Is your connection to the RPM sensor sound, did it get cracked or bent somehow? The computer will also shut down the fuel pump when a no spark is sensed.

I had a problem, upon doing my head, there have been a few posts with this same cause. Upon reassembly I missed the ground point at the driver side engine mount. For me, the engine started and I ran it for about 5 minutes, then went in the house to clean up and the engine would not start again, but there I did not have any spark, after a couple of hours of fault tracing, that ground point was just resting on the engine mount, the vibration of cranking only allowed intermittent contact.

Another possibility is the lifters over pumped and the valves are not fully closing, by just hair that is, causing low compression, lawn mower syndrome it is called. Cranking with gas pedal to the floor to shut off fuel usually get it started after about 3-4 minutes of cranking.

My manual has some go to points to check on for missing fuel pump:
Diagnostic code absent
Starter motor functions
Camshaft position ok

Look for:

Break in signal or power lead to fuel pump
fuel pump relay signal lead short circuited to ground or live
break in ground or power lead to fuel pump
contact resistance in connections
defective relay or fuel pump


I would also check for an connection pins that may have slipped out of position.
Check the big plug on the front wheel hump for a pin that may have slipped out.

Good luck, let us know how it worked out.

DanR '94 964 332,000 miles (98,000 on the new engine)




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DanR

Excellent reply Dan,
I really appreciate it. I have a feeling that it is a fault in the wiring somewhere. I'll check it out tomorrow and report back my finding, good or bad.

Thanks,
Steve

Well Dan, you were right. I took my time to look around all the engine bay for anything loose and lo and behold there was a brown wire in the back next to the cam sensor. The wire had two brown wires and a loop connector. I ground it to the engine block and the fuel pump started right up when I turned the key. For anyone else who has this problem, there's also a white wire with a red stripe, but this is a diagnostic connection, so so don't anything with that.

Thanks - problem solved!
Steve