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Join Date: Jul 2012
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Help? Calling all experts!

I messed up.
Friend came over and wanted to see if his chip was stock in his 1987 3.2.
In trying to get the nuts off his ECU box under the power driver's seat I pulled out a relay (seat?) from the rear and it shorted out on the metal floor. Sparked.
Re and re the ECU and my Weltmeister chip and put back the relay into it's plastic insulated box and now the car won't start.
All the fuses front left under hood are okay. Starter turns over but no ignition.
Is there a fuse for the fuel pump somewhere else? Any other fuses I should know about? Can't figure out why the ECU in and out would cause this problem, so I'm assuming it's the short-out of the relay that did it
Ideas?
Please and thanks. I feel terrible and he's just run out in my minivan to his appointment and I'd really like to have his car back in order when he gets back.
Cheers-
Sheldon

Old 05-21-2014, 12:02 PM
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86FlatSix
 
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Not an expert but I would look into your DME relay. Looks like it got toasted in the process. Looks like the one you pulled out under the seat is the DME relay.
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Old 05-21-2014, 12:08 PM
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What is a DME relay?
I didnt recognize it as being present in my car. Though it was for the power seats (I don't have them).
How can I check if the relay is toasted?
What do I do about replacing one if it is?
Sheldon
Old 05-21-2014, 12:10 PM
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Did you bolt the box back down? If not, you are not grounded and the car will not run right, or not start at all.
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Christopher Mahalick
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Old 05-21-2014, 12:31 PM
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Fleabit peanut monkey
 
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Quote:
Originally Posted by Pasophisto View Post
What is a DME relay?
I didnt recognize it as being present in my car. Though it was for the power seats (I don't have them).
How can I check if the relay is toasted?
What do I do about replacing one if it is?
Sheldon
See post 19.

911 3.2L G50 - DME issues

Suspect with sparking there was more juice going thru it than in normal operation.

I would just replace it. If you don't need it you have a spare. 3.2 owners talk of carrying a spare.
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Old 05-21-2014, 12:35 PM
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Here is what I'd do.
  • Turn the key on and see if the idle air control vibrates.
  • Turn the key to start and feel if the DME relay clicks.
    If it does put a meter on the fuel pump fuse in the trunk and see if voltage is present to the pump when you hold the key in start
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Old 05-21-2014, 12:44 PM
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I think that relay you pulled from under the seat is the DME Relay. I could be wrong but that's the only relay under the seat in my 85.

" 3.2 owners talk of carrying a spare."

My spare is in the glove box. These DME relays are known to be flaky.

I'd also check the fuse to make sure you have the proper amperage fuse. If something sparked and the fuse didn't blow, I'd think you might not have the right fuse.

I have a Bentley on CD for my 85 so if you need to know test procedures I can copy pages and send them to you as needed.

Last edited by cabmandone; 05-21-2014 at 01:10 PM..
Old 05-21-2014, 01:04 PM
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How big a spark are we talking here?

You pulled the cover off the DME relay and the circuit board inside the relay came in contact with the chassis?

Was it a barely visible spark or a flash with lingering smoke?
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Old 05-21-2014, 01:14 PM
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Thanks

Cool. All those replies in 30 minutes.
FIXED IT! You guys are heros.
Okay, so pulled the DME relay. Examined it next to a pic on this site as to what it should have looked like. One of the electrical solders had a bit missing in the middle- clearly disconnecting the two terminals. Looked ragged and new, like the Rocky Mountains- not the Alps. Must have blown it out with the short. Soldered a piece in there, re-installed it, fired her up. All is good!
Great to have such solid info.
Thanks again.
Sheldon
Old 05-21-2014, 01:18 PM
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I think a good question would be why were you messing around with the ecu/dme with power to them? I don't work on anything electrical with the battery connected unless it is a necessary part of the procedure. Never.
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Old 05-21-2014, 01:25 PM
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Quote:
Originally Posted by Pasophisto View Post
Cool. All those replies in 30 minutes.
FIXED IT! You guys are heros.
Okay, so pulled the DME relay. Examined it next to a pic on this site as to what it should have looked like. One of the electrical solders had a bit missing in the middle- clearly disconnecting the two terminals. Looked ragged and new, like the Rocky Mountains- not the Alps. Must have blown it out with the short. Soldered a piece in there, re-installed it, fired her up. All is good!
Great to have such solid info.
Thanks again.
Sheldon
Glad you got it running. Now tell your friend to go out and get a new DME relay, install it and keep the repaired one for a spare. Or better yet get two new ones and toss the repaired unit.
Old 05-21-2014, 01:27 PM
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Yes. Disconnect the power first. Lesson learned. I was just trying to get a nut off the ECU anchor and went to move the relay box without realizing that it would pop out of it's sheath. An accident, but an error none the less.
I popped my ECU relay out and gave it to my friend, then went online to buy another for myself- Our hosts sell them for a reasonable $35 or so but shipping (another post subject altogether) to me in British Columbia was $39.00. I called to speak to Wayne as his posts suggest elsewhere when the shipping doesnt add-up (1" x 1.25" x 2.25" = $32?) but they were closed and I got recordings. Bought one (same brand) on ebay for $41 plus $7.50 shipping. Probably should have bought two.
Old 05-21-2014, 04:53 PM
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correction

Don't want to slag inappropriately: My typos- the part from PP is $39. The shipping to Canada quoted was $32. USPS ground.

Old 05-21-2014, 04:56 PM
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