Cylinder not firing, cas?

[invain]

I was having problems with cylinder #2 not firing a while ago, and after checking a few things out, found a bad wire coming from the plug off the cas on the distributor. I replaced the chunk of wire and everything was back to normal. I've driven the car a few hundred miles since with no problems. Today I took a quick trip into town, and on the way back I noticed a big loss of power/the car running like ****. When I got home I pulled the spark plug wires and sure enough, cylinder #2 is not firing.

There is spark from the distributor and we swapped in a different spark plug; no luck. I know there's spark, so we figured it's fuel. Just to make sure the wire I patched up wasn't bad again however, we pulled the ecu and did a continuity test; the wire was fine. Checked all the injectors, 11.6 ohms on all 4. Thinking the injector in cylinder #2 might be gunked up or stuck closed, we swapped injectors with cylinder 1. Fired it up, no dice. Cylinder #2 is still not firing. We checked the ecu for codes, only thing it showed was 77 (rear 02 sensor). Refreshed the ecu, fired the car up again. No luck again.

When I had trouble with cylinder #2 not firing before, it seemed to be really intermittent. One day I'd drive the car and it'd be fine. Next time I jump in it I'm running on 3 cylinders. I'd drive to get groceries, the car would run great on the way there. On the drive back home it'd start running like **** again. Everytime I pulled codes from the ecu and refreshed it the car would seem to run fine again for a little while, then the problem would come back the next time I drove the car.

Is there anyway to check the CAS? Could the CAS go bad and only affect one cylinder? I have no clue what else this could be, it's mind boggling. Spark is fine, injector is fine.

[grecco28]

check comp. test all cyls. and if poss. cyl. leak.. inyectors ground and harness...check exesive valve clearence..if ok, try another ecu...

good luck..

[invain]

Already done a compression test.

I do have another ecu, although not tuned, I can throw it in tomorrow to see if that changes things.

[invain]

I'm still curious if there's any way to test the cas.

[invain]

Just checked the voltage at the plug for injector #2 and it showed about 5 volts. Plug from a different injector shows 9 volts, which makes sense. So I'm getting a signal to injector #2, but it's not strong enough.

[invain]

Well, we swapped in another ecu I had and cylinder #2 magically started firing again, so it looks like I've found the problem.

[the converted]

Cool that you got it going again, but it does sound like you have some other problems going on. You should have 12v at the injector plugs so I would double check the connector by the headlight that has that wiring in it and make sure that its in good condition. Also I'd pop open the old ecu and make sure that the injector driver wasn't cooked.

[invain]

Damn thanks for the info. What connector by the headlight are you talking about? I'll definitely check that stuff out tomorrow.

[invain]

Are there any sites that show layouts of the ecu's as well? I've popped mine open to see if anything was visibly burnt but I have no clue where the injector drivers are.

[the converted]

You'll be looking for a transitor that is mounted up against the ecu case to use it as a heat sink. The connector is up by the battery. I can't remember exactly how many wires are in it but there are 4-8. The wire your looking for is red and is the common power feed for all of the injectors.

[invain]

Spent all day checking wires/connections and have made no progress. At this point I have no clue wtf is going on unless the cas is bad.

Can a malfunctioning cam position sensor cause only one cylinder to misfire? We checked all connections to the cas according to the fsm. We checked all connections to the injector. Fixed a small short in the power wire to injector 2 so it now shows the correct 12 volts. We've used two different ecu's with no change in cylinder 2.

[invain]

Is there any way to test if the cas is correctly sending a signal/s while the car is running?

[the converted]

I can't think of any way that the actual sensor could go bad like that. I would check the wheel inside and make sure all of the windows are in good shape. Other than that you could spin the distributor by hand and watch the voltage on a meter.

I just read everything over again and have you tried swapping plug wires or a new cap and rotor? Just another place to look.

[invain]

Distributor is pretty new along with the cap. We took the cap off and checked stuff out last night and the 4 windows looked fine. I've checked for spark multiple times and it shouldn't be an issue.

I'm gonna go borrow a noid light from a friend and do some checking to see if the ecu is sending any signal at all to that injector.