Fuel pump does not run!
09-12-2002, 03:46 AM
#1
Cruisin'
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Fuel pump does not run!
Hi all!
I got a 911 SC 1978 model.
Now, when i turn the ignition on usually i heard the summing of the fuel pump working. As the topic here describes u would probably guess that it's not working anymore.
I did some testing yesteday and found that battery voltage is not present at terminals 87a and 86 in the fuel relay socket (with key ON). So, accordingly to my Bentley Publishers Service Manual for this car I should look for breaks in red wire between relay socket and fuse panel. I will check this today, but I have a feeling I've missed something. With the key ON i should see some oil-lamp and parking brake-lamp and such as well? I don't. All the fuses seemed OK when i measured them. So, is the battery voltage missing somwhere here? Could it be that the key-housing itself is faulty and does not deliver +12V to where it should?
~eJensen~
I got a 911 SC 1978 model.
Now, when i turn the ignition on usually i heard the summing of the fuel pump working. As the topic here describes u would probably guess that it's not working anymore.
I did some testing yesteday and found that battery voltage is not present at terminals 87a and 86 in the fuel relay socket (with key ON). So, accordingly to my Bentley Publishers Service Manual for this car I should look for breaks in red wire between relay socket and fuse panel. I will check this today, but I have a feeling I've missed something. With the key ON i should see some oil-lamp and parking brake-lamp and such as well? I don't. All the fuses seemed OK when i measured them. So, is the battery voltage missing somwhere here? Could it be that the key-housing itself is faulty and does not deliver +12V to where it should?
~eJensen~
09-12-2002, 06:05 PM
#2
Make sure that all the wires are securely fastened to the fuse connection terminal. Sometimes the small screws get loose and you can have an intermittent problem from the wire not having a good connection to the terminal. I have seen this happen many times.
09-13-2002, 10:14 AM
#4
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There should be a safety switch located near the air metering plate, it should be a blue colored bosch connector between the metering plate and the fuel distributor. Unplug it and the fuel pumps should run when the key is switched on. At least it doe's on my car.
Lane
Lane
09-17-2002, 06:08 AM
#5
Cruisin'
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Thanx for your inputs guys!!
I located the problem yesterday!
It was the wires behind the key ignition switch. A poor contact there somewhere. At least I pushed the wires with my finger and suddenly power to everything was back again! I pushed the wires so they got stuck in a different position than before and now got contact. Anyway, later on I guess I'll have to take the whole thing apart to really fix the poor contact wire(s)...
btw, the fuel pump does indeed run when the key is in "run"-posistion and the engine is not started yet. Could this indicate something else?
~eJensen~
I located the problem yesterday!
It was the wires behind the key ignition switch. A poor contact there somewhere. At least I pushed the wires with my finger and suddenly power to everything was back again! I pushed the wires so they got stuck in a different position than before and now got contact. Anyway, later on I guess I'll have to take the whole thing apart to really fix the poor contact wire(s)...
btw, the fuel pump does indeed run when the key is in "run"-posistion and the engine is not started yet. Could this indicate something else?
~eJensen~