Sent you my e-mail,I still have power to my pump power plug using a test light,but gas gauge will show empty or move up slowly.I have noticed when this happens car will not start,turns over,no start.Is there something wrong with my sending unit, would this make my pump not come on even if it has power to pump?Not sure where sending unit is,if it is in tank on housing with pump or elsewhere.I see the plugs on top of housing,I think they go to the sending unit.Still can not find any obvious problems.

 

Casa - check your e-mail.....

Your pump should run briefly when the key is first turned on, assuming the fuel pump relay is getting sufficient power through it from the main power relay. Once the engine starts cranking, the PCM (engine computer) should restart/keep the pump running, assuming it sees a good crankshaft position sensor signal. If it doesn't, then the PCM will shut off the pump by opening the pump power ground circuit on the fuel pump relay.

Back to the no trouble code subject you reported earlier. If you used a code reader that only reports generic trouble codes, you may have missed manufacturer specific codes that these readers don't report. If you have access to a better scanner that can read these codes, then by all means take advantage of it.

Your sending unit shouldn't have a power effect on the pump. The pump It is driven from the fuel pump relay/PCM circuitry.

Anyway, I hope the info I sent you is helpful. I'll check back with you later...

RICK In PA - see info above. Hope this helps as well.....The pump should run for a second or 2 when the key is first turned on. After that, it depends on whether the PCM is getting the proper input and the relay circuitry is working properly. Possible relay or other grounding issues with yours? Have you scanned for any generic/manufacturer codes as well?

J

 

Highorder77- Thanks. Sounds like the cam & crank position sensors do not come into play when key is first turned on and before engine cranks, if I understand your post correctly, so I can probably eliminate bad sensors as the problem. The relay circuitry is all working correctly except for the ground terminal that the PCM controls. Will try probing the PCM wiring harness for good ground connections, I guess.

Casa-- sorry to hijack the conversation a bit. My problem is similar to yours and I thought we might both be able to benefit from Highorder77's helpfulness.

 

Rick - Not sure what year your vehicle is or what engine we're talking about (mine is a 99 w/ a 1.6). If you have that open ground, then also check the condition of your crank position sensor as the PCM may be looking for continuity through it when the key is first turned on-not sure of the program logic for that system. If it was bad, I would think you would have a hard trouble code for it. Since you did not report whether you had any codes, I assume there were none.

Casa - Will respond to your e-mails shortly. In the meantime, have you had a good look at the info I sent? I don't think the oil pressure circuit is directly tied into the fuel system in any fashion. Check the wiring diagram in the control system file I sent as I may be wrong.

Also - I suspect that the pump may not come on when the key is first turned on during a hot restart - again may depend on the programming logic and input from other vehicle sensors.

J

 

Well for the record my problem is a broken timing belt. As the car (it's a 2000 626) has 283k miles, uses 1/2 qt of oil a week, and is still on the original clutch(!), I believe I will sit on the hood, drink a beer in memorium, say a few appropriate words, and then call the junkyard.