s4 T2 rebuild/swap won't spark
 

Alright rotor brethren I have an 86 s4 that was t2 swapped. A bad fuel pump, some lean running and a rebuild later we finally have the engine back in the car and getting no spark. The battery was put in the car backwards for a second but didn't blow any fuses.

Neither the trailing or leading coil will fire but the car will turn over and the fuel pump also works fine.

I have tried 3 or 4 different trailing and leading coils. As well everything seems to be well grounded. We also get zero bumps on the tach when starting.

Something else to mention and probably entirely unrelated. When the swap was done prior to blowing the motor and the subsequent rebuild there was a short in the ignition switch which kept killing the starter solenoids so eventually we bypassed it with a push button start. Most likely unrelated as it worked before....

Check your coil wiring and make sure they are receiving power.

Apparently there isnt any power getting to my coils. Why is that tho?. I havnt messed with them.

With the key to "on," the B/Y wires, which supplies the coils with voltage, should have voltage. Are these wires w/o voltage on your car?

EDIT:

Lets say the B/Y wires were w/o voltage when the key is turned to on. The B/Y wires receive voltage from the B/G wire which runs from a 40 amp fuse in the engine bay fuse box. So the B/G wire always has constant voltage regardless of the key position as long as the battery is hooked up properly, the Black wire is connected to the engine fuse box from the positive terminal of the battery and the fuses are good. The B/G wire passes its voltage onto the B/Y wire at the "main relay." So if there is no voltage reading on the B/Y with key to on then check for voltage of the B/G wire which is constant. If there is voltage on the B/G wire then the problem appears to be focused around the master relay itself or why the relay is not receiving proper voltage and or grounding.

http://www.teamfc3s.org/info/articles/demystifying.html

if you dont feal like reading, throw a CAS and then an ECU at it.

and if you didnt know.. i'll tell you, you can turn the CAS outside of the front cover and watch the spark plugs fire... and hear the injectors pulse, and get the piss shocked out of you. sounds like a bad ECU to me, but a CAS is easy to find as they dont usually go bad, and it's a quick easy swap, compared to the ECU.

My guess its because you plugged the battery in backwards. :icon_tdow

But now you have a wire to trace. :icon_tup:

also oddly enough every time i plug the retractor fuse in it blows every time and they are not bound up either

and the power to the coils on the b/y wire it was .1 volts......hmmm....

wire can read .1vdc coiled up in a bundle.

Then I guess the next step would be to get a voltage reading from the B/G wire. Wouldn't it?

plug a spare CAS into the CAS harness, then spin it by hand. does it spark now? just unplug one leading wire from the coilpack and see if you see spark coming out from the coil

fixed. The little cluster of ground wires that gets plugged into the strut tower near the trailing coils on the s4 was not plugged in. I removed every bracket in the engine bay to paint and clean and forgot that one...