Hey there,

I've got an 850 that just up and died a few weeks back. Previously it had some trouble starting, and upon removal and re-installation of cam position sensor (not replacement, just took it out and put it back in), it worked okay.

This time, it quit out on the highway.

Current status: I'm only getting spark on cylinder #1 (closest to timing belt, yes?) Using timing light, I literally am only getting a pulse from coil for this one cylinder. I've looked at the spark signal (with the timing light) on a working 850 (neighbor's), and I get a spark through the coil cable once for every cylinder. On mine, only for cylinder #1, and you can hear it fire on that cylinder when you see the timing light flash.

Also, I have no error codes.

I replaced (with junkyard parts....) the cam sensor and rpm sensor, and verified timing belt is on and lined up correctly with marks on cam pulleys. Distributor is good (recently replaced), and coil was replaced and deemed to be not the problem. I also got an ECU from the junkyard (all salvage parts were from "working" vehicles when they came in, but who knows....), and I still get only spark on one cylinder.

Anybody see this before? Can a bad sensor only allow the ECU to fire the coil for one cylinder?

Anybody ever seen a pareto chart (shows parts that fail the most, and their failure frequency) for an 850? Seems like it would be very helpful!...

Thanks,

Mac

Something sounds fishy. If you get spark to one cylinder you should get it to all.

And if you aren't then there is a problem with either the Dist Cap or rotor.

Of could it be the highly unlikely case of all four of the five distributor cords are not working properly...?

:blush:

If there any way that a timing light will fail to flash if a spark signal is sent down a wire? The Haynes manual says not to check the spark with a "screw driver to the frame", etc, as it might hurt the coil, or whatnot. If a spark plug breaks, or a sparkplug wire breaks, and the spark isn't firing, wouldn't that prevent the timing light from firing, since there'd be no "current" for it to sense, even if it is connected around the ignition coil cable?

Has anyone else used a more positive spark test than the timing-light method, without hurting the ignition system?

I'm changing out the spark plug wires tomorrow, in any case.

Mac

Lets see how that goes...