# Digifant ECU repair due to bad ground



## Str8pipingti (Oct 10, 2010)

Well I Did not install the ground wire that runs along with the o2 sensor wire, big brown wire. now the car will not start. I tested all the resistors and diodes in the ECU itself. Someone out there knows what I am looking for and I am needing some help on identifying what would make no spark due to not properly grounding this one wire. This is next to the 3 wire o2 sensor, runs right next to it. Now i got it on the intake manifold. I burnt up 2 ECU's bc of this. It is very easy to fix, but I am not sure exactly what I need. 

Thanks.


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## Fat Rabbit (Nov 18, 2001)

Your post makes no sense. The ECU ground usuaslly connects to the cylinder head at one of the bolts or studs for the hose flange at the transmission end of the head. The injectors work by grounding through the ECU. Without that ground connection the ECU flashes over internally to find a ground. That ruins the ECU. You are still two ECUs short of the Vortex record which is four ruined ECUs. There is likely a way to repair ruined ECUs if one is talented in electronics repair. Most folks simply replace them. FR.


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## Str8pipingti (Oct 10, 2010)

well let me clear this up. the ECU grounds are in the right spot. Main GND from battery to trans/block bolt, Main ground to fuse block, ground from harness to chassis GND(under dash on the post) and the GND wires from the harness to the battery. AS for that GND I was talking about, it is the one the runs next to the 3 wire o2 sensor harness coming from the rain tray area next to the coil. When i looked it up through A2 resource.com. It told me it was ECU ground,brown. 

The issue I am having is no spark. New coil. 
It is not flooding the cylinders, so I think the ECU is still good. 

All these parts cam from a good running car. The original harness was a digi1 and i had a bad tps and could not get a good one. So when I did the aba swap i swapped to digi2. Also b/c I already had a chip for it.

Sorry for the unclear post. I was a little P.O.ed at the time. Never had this happen to me before. I've done 16v, 1.8t, vr6,24v vr6 swaps and no major issues like this.


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## Fat Rabbit (Nov 18, 2001)

I thought there was more to the story. A2 Resource is correct. The brown wire in with the O2 wiring is the ground from the ECU. You could check the grond by locating the connection at the ECU harness connector and checking for continuity to ground. It sounds, however, like you have an ignition issue instead. Most manuals have procedures for checking the Hall sender and the Ignition Control Unit. I would start, however by checking the ignition switch then working through the system from there. Those switches tend to go bad and often won't energize circuit 15 - the run circuit reliably. I usually check for power in that circuit at the coil terminal. It should be powered in the start and run positions of the key. I have also had issues with the connections on the back of the fuse and relay panel pulling out slightly and causing the car not to run. The simple fix is to firm up those connections by reaching around behind the panel. FR


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## Str8pipingti (Oct 10, 2010)

Ok. this is where I am at now. The distributor is a new one from GAP. The coil as well. I also swapped in the old parts to test with. I do have B+ at the coil in run position. The Hall is getting 12v. Timing is spot on. Should I get another ICM?


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## Fat Rabbit (Nov 18, 2001)

You should be able to test the ICM without buying one. Also don't forget to check the wires for opens and shorts. Junkyard parts can work just fine. FR


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## Str8pipingti (Oct 10, 2010)

Would you happen to have a spare DIGIII?


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## Mr.loops (May 27, 2010)

Str8pipingti said:


> Would you happen to have a spare DIGIII?


PM sent


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