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No Spark Leading Coil, CAS?

Old 02-13-19, 07:26 PM
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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....
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Old 02-14-19, 11:25 AM
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How did the problem arise? What changed before this happened or did it just happen out of the blue?
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Old 02-14-19, 11:46 AM
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Originally Posted by Rotary Alkymist View Post
How did the problem arise? What changed before this happened or did it just happen out of the blue?
I've rebuilt the engine myself and installed it although I bought the car with the engine already removed not by me, but by questionable people lacking some skills to be nice...But messing more with it last night,seems turning over the engine with a ratchet wasn't fast enough. I've got it to spark with the CAS installed albeit a weak spark compared to the trailings (showing 1.0-1.5 volts when it sparks on the lead coil green/yellow signal wire) not totally sure if this is enough voltage, I thought I read some where it needs to be 4-5V for the signal.

I'm thinking now some fuel injector plugs are mixed up and I'm gonna verify those are clipped on to the right ones.
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Old 02-14-19, 11:58 AM
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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 .
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Old 02-14-19, 12:01 PM
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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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Old 02-14-19, 12:08 PM
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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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Old 02-14-19, 12:17 PM
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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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Old 02-15-19, 04:25 AM
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Originally Posted by Rotary Alkymist View Post
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.
Ok she starts now and sounds healthy! After pulling the UIM and checking the injectors. I noticed when I jumpered the fuel pump check connector and applied fuel pressure one of the secondaries was just dumping fuel into the intake and was stuck in the open position. I swapped the injectors with a brand new set I had laying around and all is good I suppose I was chasing a problem that wasn't there with the ignition...BTW get quality injectors! The injector that was stuck open was a aftermarket, less than 3 years old , no name, no flow sheet or inj. data pro
bably china made.
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