SR20det weak spark in cyl 3

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Cerevo
Posts: 74
Joined: Mon Feb 01, 2010 8:08 am
Car: 97 240 base

Post

I'll save the long story, Car starts and runs, has a dead miss in cylinder 3. I know this because you can unplug the coil packs one by one and they all make a difference except cyl. 3. Same thing for the injectors. All the injectors pass the "cardboard test" and spray on the cardboard.
We took the coil off cyl 3 and put a plug in the end, and held it to the valve cover and got a large orange flame instead of a neat spark. We did this same thing with the cyl 1 coil and got a neat small blue spark. We did this two separate times to confirm it.

I feel like the ignitor is bad. This is the second engine I have had in my car with the exact same problem. I've changed and gapped all the plugs, changed ECU's, changed all the coils, changed the coil harness, I have a wiring specialties conversion harness so all the wiring and connectors are new. The only thing I have not changed out is the ignitor because I don't have a spare.

Can an ignitor cause only one cylinder to have a weak spark?


Cerevo
Posts: 74
Joined: Mon Feb 01, 2010 8:08 am
Car: 97 240 base

Post

Several things: ecu was tuned and running pig rich, cylinder 3 had low compression due to a screwy intake cam, also had some vacuum leaks.


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