Project Shrek: electric riddle
03-05-2010, 12:30 PM
#46
Have you checked the flywheel sensor gap - sorry to bang on about it but the symptoms you describe kinda point to it. The pump primes then waits for a certain rpm from the flywheel before running - if its getting no signal it wont run.
03-05-2010, 09:35 PM
#47
Rennlist Member
That is a normal prime function as the above poster stated also. It's what happens AFTER that. If you are losing power to the fuel pump, then one of the pin out checks on the DME relay CANNOT be correct. This is where it gets power from. Something is missing for this to happen. Whether it be a flywheel sensor, alarm issue, whatever, but something is missing. Thats why it's important that you do the pin out test on the DME relay, so we can figure out which way to go from there.
03-09-2010, 06:42 PM
#53
Burning Brakes
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Dear GeorgeK
"It does raise a few questions." It's a Porsche miracle
"Is there in fact really an overload protection somewhere in the DME?" Copper wires in the pump motor have the inherent characteristics of increasing in resistance as heat increases and if resistance increases conductance decreases in turn built in thermal shut down. But not likely enough heat can be generated in the 1/2 second it runs and I would think the fuse would blow before it got to that point.
"Does my mechanic in fact know what he's doing?" He has the advantage of sight, sound, smell and touch physically being there. Maybe his ofactory sensors detected burning wire insulation - a tell tale sign of taking too much current but then again I would think the fuse would blow before it got to this point.
There's no substitute for experience.
Bill
"It does raise a few questions." It's a Porsche miracle
"Is there in fact really an overload protection somewhere in the DME?" Copper wires in the pump motor have the inherent characteristics of increasing in resistance as heat increases and if resistance increases conductance decreases in turn built in thermal shut down. But not likely enough heat can be generated in the 1/2 second it runs and I would think the fuse would blow before it got to that point.
"Does my mechanic in fact know what he's doing?" He has the advantage of sight, sound, smell and touch physically being there. Maybe his ofactory sensors detected burning wire insulation - a tell tale sign of taking too much current but then again I would think the fuse would blow before it got to this point.
There's no substitute for experience.
Bill
