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89 FC S4-ignition-bypassed board problem

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Old 12-12-17, 10:28 AM
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89 FC S4-ignition-bypassed board problem

before i start. Please dont be a dick. I have read alot of threads. I have not found anything like my buddys problem.
He has a S4 FC vert. He crashed the car last year. We did a chassis swap with all his gear. It ran before the swap.He was a little over eger at times and started yanking wires that had been installed after market for bypassing the ignition coils ( i guess) with a toggle for deflood/Fogging the engine from what he told me. The previous owner is missing in action. The way he did it was on the ecu board itsself. With a nest of white wires coming from under the cover. Does any body know of a mod out here on the net, that does this? Everything works on the car. Just no matter what we try, even swapping to another harness no spark from the coils.
There were a set of 6 white wires. White in color, twisted pair with milar sheilding inside. They looked to me as standard avionics wire. The first pair went to a toggle switch in the center console just behind the shifter and ebrake. The other four wires went through the firewall on the passenger side to some where on the engine. He had pulled the engine before i got there and did not think to ID the wires with tape. Then he didnt remember!! where they went..OH! joy! lol.
He has power to all things. Signal leaves the CAS to the ignitors,but nothing leaves the coils to the engine. We have swapped coils to new ones and back again ,with no change in condition. I think he and another friend even went so far as to swap harnesses as well and try another different ecu from what i have been told. No changes in condition. Engine spins at the normal start speed. Has fuel.New plugs proper gap.
I dont know what else to do to help him. other than Brand new harness.

Last edited by CAF- FC; 12-12-17 at 10:49 AM.
Old 12-15-17, 08:22 PM
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Originally Posted by CAF- FC
He was a little over eager at times and started yanking wires that had been installed after market for bypassing the ignition coils ( i guess) with a toggle for deflood/Fogging the engine from what he told me. The previous owner is missing in action. The way he did it was on the ecu board itself. With a nest of white wires coming from under the cover.
Wait, so these wires are hanging IN the ecu itself?? Also, this would make it a flood switch. You're supposed to cut fuel, not ignition.

Originally Posted by CAF- FC
The first pair went to a toggle switch in the center console just behind the shifter and ebrake. The other four wires went through the firewall on the passenger side to some where on the engine. He had pulled the engine before i got there and did not think to ID the wires with ta theype. Then he didnt remember!! where went..OH! joy! lol. He has power to all things. Signal leaves the CAS to the ignitors,but nothing leaves the coils to the engine. We have swapped coils to new ones and back again ,with no change in condition. I think he and another friend even went so far as to swap harnesses as well and try another different ecu from what i have been told. No changes in condition. Engine spins at the normal start speed. Has fuel.New plugs proper gap.
I dont know what else to do to help him. other than Brand new harness.
The situation seems pretty dire unless you find the previous owner or trace the wires to where they come from in the board and where they go.

Also, have you verified your fuses and relays?
Old 12-18-17, 04:18 AM
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What is the N number on the ECU?..
Old 12-18-17, 12:12 PM
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With a nest of white wires coming from under the cover.
I dont know what else to do to help him. other than Brand new harness.
I don't understand why you think changing the harness will help? Are the wires spliced/jumpered at the harness or are they jerry-rigged and coming out some weird part of the ECU?

Either way; it'll help us to have an ECU number and some pictures of exactly what we're looking at. Hard to diagnose wiring issues without a schematic, physically being there to test it, or at least understand what's going on. If the wires are coming out of the ECU I'd be interested in seeing what the internals are looking like also.
So: ECU number, pictures of harness, wiring at console and in engine bay, and under the ECU cover if wires are literally coming out of it.
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