No Spark Leading Coil, CAS?
Background; Series 4 Turbo 2, stock wiring harness, PFC ecu, banzai PnP harness adaptor, fresh rebuild (great compression! new housings:), runs on trailings only no spark to leading plugs..
I'm totally stumped right now as to why this car WILL NOT fire the leading plugs when the CAS is installed/stabbed in the front cover. It WILL fire the spark plugs properly when it is removed and I turn it by hand. I have verified this with the spark plugs removed and still connected to the leading plug wires and visually watching them spark. I have taken the cover off the top of the CAS when it is installed in the engine and verified it does turn when I crank it over manually by hand with a ratchet. Some things I have replaced/tried: two other working CAS's, two other lead coil assy's, different plug wires, stock ecu, added grounds...also a note the trailings fire properly as they should no matter the location of the CAS. Also this car has ran before with this exact set-up very well! although prior to a front iron cracking and spewing oil...ANY help is appreciated, I've been fighting this the last 4 days and reading/searching and I'm running out of ideas to try.... |
How did the problem arise? What changed before this happened or did it just happen out of the blue?
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Originally Posted by Rotary Alkymist
(Post 12330256)
How did the problem arise? What changed before this happened or did it just happen out of the blue?
I'm thinking now some fuel injector plugs are mixed up and I'm gonna verify those are clipped on to the right ones. |
Just spit balling here: You could check to see if one or more of the 4 wires(ECU terminal N,P,Q,T(CAS signal wires)) have any relation to ground while plugged into the front cover.
You could also try grounding the braided shield that all four wires run through. Edit: Ok so you are indeed getting spark. That's good then :). |
If you turn by hand and observe voltage reading you should see two jumps per revolution of 5v(hope I'm remembering correctly here)... it's easy to move past it with a digimeter. An analog meter would work much better but you should see the jump with any meter.
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I've done this test several times but with a DMM not an analog and I only see 1.0-1.4 volts max during a cycle...I need a analog meter really, I may go get a cheap one if I can find it just for this test. Or call a buddy with a good running 7 and check their signal wire on the coil.
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Have you tried moving it in really small increments? I mean, reallllly small. I can remember that I had to move it really slowly and that once you find it it will stay at 5v until you move the crank again, but only at that exact spot. Hope this helps.
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Originally Posted by Rotary Alkymist
(Post 12330268)
Have you tried moving it in really small increments? I mean, reallllly small. I can remember that I had to move it really slowly and that once you find it it will stay at 5v until you move the crank again, but only at that exact spot. Hope this helps.
https://cimg7.ibsrv.net/gimg/www.rx7...971b63aabb.jpgbably china made. |
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