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scojo · Joined: 04 Feb 2015 Posts: 2 Location: Boise Idaho

So for the past couple of weeks I've been starting this car using the "Jumper" method. 30-87-87b. It starts and runs great. I purchased a new DME and I hook it up, fuel pump powers up, car turns over however, it doesn't start. Hook the "Jumpers back up and it fires right up and runs great. Any ideas on how to address this problem. Thanks for any suggestions.

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

DME or DME wiring fault is all I can think of.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

So obviously you have power at 30 and good wiring for 87 & 87b.

You need to check for continuity between terminal 85B & the ecu. You should have a good ground at terminal 85 & power at 86.

scojo · Joined: 04 Feb 2015 Posts: 2 Location: Boise Idaho

Could this be an issue with the (85b to ECU) problem. Basically wire labeled "A" the red with blue connector was attached to post "A". It looks like someone connected it to the black and purple wire going into the relay next to the fuel pump relay. To me this doesn't look like a stock splice. I would like to get this back to stock so when I'm trouble shooting I don't have to factor in what someone has changed in the past. Any info appreciated.

http://i1061.photobucket.com/albums/t477/scojoraft/wires_zps35dc361b.jpg

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

If you want to fix it correctly, remove their spliced in wire off of the DME relay. 30,87 & 87b are working fine.
With the relay out check;
85 for ground
86 for 12V with the ignition on
Check 85b for a ground with the relay in & motor cranking. If none, check for continuity between the wire that goes on 85b & terminal 20 of the ecu. If you have continuity, temporarily ground terminal 85b of the relay without the DME wire (grey/black) hooked to the relay.
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