Ignition coil signal...for the smarties

[simbey1982]

Ok all,

 

here is the situation. As many of you know, I am putting a 99 2.5 SOHC (MAF Based) in my 97 impreza body. I have the new engine in, the right ecu and the wiring is spliced in. Fuel is getting to the engine and the air intake seems to be fine, but we are having trouble with spark.

 

I get weak spark across one coil and none across the other. There are four wires going to the coil/ignitor one for ground (reads at like 2ohms so its grounded), one for ignition switch power (reads at 12V) when the car is on run, then there are 2 signals, there is continuity from the ECU to the coil over the wire. When the engine is kicked over, one of them gets an alternating voltage (like it should) and the other gets NO voltage.

 

My only guess is there is something else that controls the signal coming from the ecu to spark...what is that??

 

Oh yeah i have ruled out the coil pack itself as i had a car there with one and mine worked fine in it and the good one from the other car exhibited the same problem when in mine.

 

Lets just say this all makes and engine that doesnt work, We are wondering if the timing being off would retard anything or keep it from sparking as a safety feature or something??

 

Any help would be a Godsend....im desparate :-\ :-p

 

The above emoticons show the emotional roller coaster of an engine swap

 

Cory

 

PS i had a little engine ground wire that was cooking to death from over current. The engine ground is hooked up and secure but i still had to add another strap to keep it from cooking...dont know if this helps but i thought i would include all relevant info

[idosubaru]

a wire that was cooking? did you find what wire that was and remove it? i'd trace that wire and see if it compromised anything else. i've seen shorted wires burn through master cylinder caps, speedo cable coverings, wires, etc.

 

what kind of wiring changes did you make? did you have to swap any wiring or was it a plug and play type of deal? a 99 2.5 should plug right into a 2.2 harness right?

[simbey1982]

it was like a 18 guage ground wire going from the engine to this block of solenoids and vacuum tubes...thats what was cooking...so i added a beefier strap to that

 

i had to get the engine side of the harness from the 2.5 its very diffrent from the 2.2....so i had to splice in like the ECU power, air conditioning, grounds, fuel stuff etc that exists seperate from the sensors but is either monitored or controlled by the ECU.

[nipper]

Timing belt off by a tooth, the car will not start. Why are you so sure it is not the coil pack. I would look at the ignitor (which actually fires the coil) first, then check the cam and crank position sensor. i am not sure, but it should be running off the cam sensor.

 

 

nipper

[simbey1982]

thanks nipper...we have been very apprehensive about wether its the timing...so we are gonna tear into it. The ignitor and coil are all one unit in the newer models