C4 broken ground wire to ?
Thread Starter
Cruising
Joined: Jan 2013
Posts: 14
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C4 broken ground wire to ?
I found a broken wire behind the battery when I replaced the battery in my new 90 convertible. I traced it in the wiring harness to where it grounded to the frame beside the alternator. Does anyone know what it is the ground for? Three wires ground at this spot. Two are grounded together-this wire is grounded separately.
Cruising
Joined: Nov 2012
Posts: 13
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I'm tore 9layers deep in my 88 right now. Looking for what I suspect is a Ground issue. If I find anything on that wire i'll let you know. My problem is all the "Accesssorys" quit working; Stereo, Climate Control, Seat operation, Interior Lights... Everything you need to operate the Car still works; Lights all around, Engine, Digidash etc... If you know what this problem could be please lmk. I suspect there all grounded to the same location. With your issue, being that it's a pain to find the other end of most wires on these Nightmars. Sometimes the easyest thing is to just unplug it and see what stops working
Thread Starter
Cruising
Joined: Jan 2013
Posts: 14
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I share your pain. Only the radio is dead in my 90. I put in a new chip and now the car only operates in limp home mode, but that is an improvement over how it was running.
Rather than a ground problem om your 88, since these accessories have multiple grounds, I would switch the two circuit breakers in the fuse panel -pwr wdo and pwr acc- and see if something comes on. If the power windows aren't working either, check both circuit breakers for continuity. If still no go, I would check the fusible links behind the battery.
Rather than a ground problem om your 88, since these accessories have multiple grounds, I would switch the two circuit breakers in the fuse panel -pwr wdo and pwr acc- and see if something comes on. If the power windows aren't working either, check both circuit breakers for continuity. If still no go, I would check the fusible links behind the battery.
Thread Starter
Cruising
Joined: Jan 2013
Posts: 14
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I know it is a ground wire because the grounded end is still attached to the frame just in front of the upper a arm mount. I pulled on the foot or so of wire behind the battery and saw the grounded end sliding into the loom where it popped out to go to ground. If the broken end pulled out of the firewall connector I cant find a terminal there that is missing its wire.
Cruising
Joined: Nov 2012
Posts: 13
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Fuses and Breakers all good. That was the first thing I tried. I have power at all of these components Audio, Climate Control, Blower Module, Door Dingie etc...I suspect Ground issue because they have power but, they don't work. They may all share 1 common ground location. There are so many wires behind this Dash it's like looking at a Chinese Autobiography
Thread Starter
Cruising
Joined: Jan 2013
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I will assume you know you have power "at" the radio, for example, because you actually probed the connector with a voltmeter. That said, why not run your own ground from the ground wire in the connector to ground ? This should tell you absolutely if a no ground condition is the problem. Caution, though, as other accessories may try to pull voltage through the only ground available to them.
Safety Car
Joined: Apr 2011
Posts: 3,660
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Look at the very detailed drawings in the FSM to guide your search...
The car is managed by control or "power grounds" for every function. The power source with fusable links is all grouped from a single spot as well.
The important ground bundle is on the eng block. Look at the trunk line under the wiper motor, follow the 5 drop downs to the block.
The car is managed by control or "power grounds" for every function. The power source with fusable links is all grouped from a single spot as well.
The important ground bundle is on the eng block. Look at the trunk line under the wiper motor, follow the 5 drop downs to the block.
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Thread Starter
Cruising
Joined: Jan 2013
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Thanks leesvet and Hellsrazor for your timely help. I don't have the service manual, yet, but it is getting easier with every new problem to justify buying it. Not sure if leesvet 's advice was for me, Hellsrazor, or both, but I will trace the drop downs as soon as I can get my propane tank refilled -high temp today was 21. Thanks again.
Thread Starter
Cruising
Joined: Jan 2013
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Chip is in new memcal. Compared new to old memcal and found both chips with notch on outer end. 90 memcal has keyed base that prevents reverse installation into ecm. I don't want to monkey with it yet because the company that made it hasn't had a chance to see what went wrong. So in your experience putting a chip in backwards doesn't always destroy it , despite dire warnings in instructions?
Pro
Joined: Feb 2010
Posts: 677
Likes: 3
From: Metairie LA
In my case, doing my own burns, the chip is placed into the zif socket of a Moates GP1 adapter. I have put them in backwards and then started it. It ran like crap and the CEL was on as well as the coolant fan. Turned the chip around and started- all good.
I'm not sure what setup you are using so - it was just a suggestion.
I'm not sure what setup you are using so - it was just a suggestion.
Thread Starter
Cruising
Joined: Jan 2013
Posts: 14
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Could you program a chip for a 90 with a broadcast code of 4294 ANHW to the OEM specs?
I'm trying to get rid of an old aftermarket performance memcal that is fouling out plugs in 15 minutes. It does, however, seem to run everything except engine management correctly. I have no experience with removing a chip from its carrier so I got a completely new memcal.
I'm trying to get rid of an old aftermarket performance memcal that is fouling out plugs in 15 minutes. It does, however, seem to run everything except engine management correctly. I have no experience with removing a chip from its carrier so I got a completely new memcal.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The chip with the programming in it is the large one on the left with the circular window (used to erase the old programming with ultraviolet light). This chip comes from the factory soldered into the MEMCAL, so it requires somebody with soldering experience to remove it. The easiest way is to pull the chip out with the pins still attached and then desolder the pins, remove the solder and put them back in the MEMCAL.
The two smaller chips are resistor networks that control the ECM in "limp" mode. This is a 1227165 ECM, used in '86 - '89.
The two smaller chips are resistor networks that control the ECM in "limp" mode. This is a 1227165 ECM, used in '86 - '89.
Last edited by Cliff Harris; Feb 3, 2013 at 03:03 AM.