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rsrmike rsrmike is offline
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Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
Hey Bill, Sounds like the control unit my be giving up. The DEI relays sure sound like alarm system. That may be something to consider as well. I've pulled many a aftermarket alarms off of Porsches and chunked them as far as I could. They can really lead to trouble depending upon how invasive a system it is and how crappily they were installed (scotchlocks, wires run through sheet metal with no grommets, etc.) Not sure it would affect your control unit unless whoever installed it was industrious enough to tie in some sort of fuel pump kill to your relay circuit. Probably not but you never know. Let me go get under the seat of this 91 and refresh my memory and see why that relay is there. I know the Ignition relay is mounted in the engine compartment so this obviously does something. The rest of the wiring was pretty simple once I figured out what I needed for it to run. I looked at the wiring diagram some more after my last post and noticed it tied into the ignition relay as well. I'm not sure why actually, not sure I ever figured that one out before. Now I wonder if that control unit also had some sort of time delay built in to power the ignition just a few seconds after shut down. I know the older cars had this built into the ignition relay so it's possible Porsche saw fit to include it. It certainly helps when the CIS gets older or if you've got your system pressure cranked up for hairy cams to keep it from popping upon shutdown. The mufflers catch enough hell, they don't need another ka-boom... I'll get back to you on this one
Old 02-02-2008, 02:26 PM
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