[DML] Fuel Pump Madness

["Todd Nelson" <tan5732@xxxxxxx>]

List:

I think I've done all I can do with this one, so I'm going to open it up to you all.  After taking the car out of storage for the winter I noticed that when I turned the key to the ON position the fuel pump didn't do its regular 2-3 second prime then shut off.  Hmm I said and continued to flick the key from ACC to ON. Finally the pump did its deal and the car started fine.  I shrugged it off as some corroded contacts and went on my merry way, only to find that the problem was back when I tried to restart again.  The same "solution" of flicking the key seemed to work.  I have been told that it may be dirty contacts on the ignition switch, but I don't think this is it since the main relay for the ON position always works, and everything else that is supposed to come on when in the ON position (dash lights, engine electrical components, etc) all work fine.  I first suspected the RPM relay, so I opened it up, cleaned the contacts on the relay and the same problem continued.  After A LOT of testing I came to the conclusion that the RPM relay was dead, I've heard they are prone to failure and I had an original one, so it all added up.  $57 later at my local foreign parts shop and my troubles continue!  But at least I have a spare RPM relay now.  During my testing I noticed that if I quickly (really quickly) plug and unplug the #1 fuse a few times things will work, but if I slowly plug and unplug the fuse things will not.  Same goes for the key, if I quickly flick to the run position a few times the pump will run for those 2 seconds as it should.  I've studied the wiring diagram of the car until migraines set in and I can't seem to find anything else on this circuit to prevent the pump from pumping.  It's not the inertia switch, I've bypassed that.  I was also thinking possibly the "main fuel relay/LAMBDA relay" as it is on the circuit.  But even with that unplugged the symptoms are the same, the pump will still function (sometimes) with that relay removed, so that can't be it.  I've cleaned all the contacts on the fuses, pump connections, relay connections and ground points.  Once I get the pump going the car runs and drives fine.

Any thoughts?

Thanks,
Todd Nelson
1561, Vermont
http://www.rit.edu/~tan5732


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