Testing coils on a coil over plug system?

[art leong]

Originally Posted by buzzinhalfdozen

Art, I'll assume the cam sync lite blinks now? Do you mean it still doesn't start, or it starts and stalls when put into gear? I'd say if the coil is capable of jumping at 40,000 volts it's sufficient. So we're back to the basics, Air, Fuel, Spark. Perhaps we could try this test, hook your meter to the wires crank sensor wires @ the ECU, assuming the engine starts, set to AC voltage and start engine if possible raise RPM, the voltage should increase with rpm. The .4 volts AC seems pretty low to me however I'm sure different sensors can produce varying amounts of voltage. IF in fact the engine does start now you must have at least some trigger input to the ECU.By the way what supply voltage did you decide on for the cam sync? Also how much timing do you have ?

It starts but still has no power.
At idle I run 26 degrees timing. I put a couple of sewing needles in the connector for the crank sensor. And started it up. I get 9.5 volts AC when running.
One thing I did notice was the timing was jumping a bit on cylinders 1 and 2 It was sort of missing. It would miss and the timing would jump.(only on those 2 cylinders though) I'm going to get my wife to hold the timing light and try to tell me what goes on when I put it in gear. I didn't change the supply voltage. Because it ran fine before and I don't want to get 10 miles from where I started. When I make a change I always try to bring it back to the start point, to see if the change worked.

[buzzinhalfdozen]

OK, so the timing seems to jump a bit and you seem to have an intermittent misfire on 2 cyls. For the timing to move you almost certainly have to have a few missed samples on your target wheel ( crank wheel) that or if you have it set up this way it's falling into another "cell" in your timing matrix. Obviously if for instance the sensor "misses" a few teeth on the wheel it will have no reference to initiate triggering of the coil. Of course a "miss" on the cam sync would most likely cause the same concern. Have you measured the air gap of your sensor and if so have you tried moving it closer or farther away? How bout the run out of the wheel, does it have any radial run oput? A fluctuating run out of the trigger wheel can cause it to lose signal. Man so many possibilties. Would it be possible for you to rig up a test lite using a very small bulb... maybe a 194 hook one lead to power and the ather tap into the injector "drive" circuit, the ECU drives the injector by suppying ground to it. Rigging this up would indicate an issue if say it misses a few pulses... either the ECU driver failed on that cycle or it saw no trigger. Have you ever looked to see if your system shows a real time tooth count for either Crk or cam sensor? Some systems have this some don't, if it does it would make diagnosing the sensors very easy.