'94 drivability problem

[channelmaniac]

There's no real way to test an intermittent CAS... unless you have an oscilloscope to watch the signals... and provided you know what you are looking for on the signals...

Best way is to swap 'em.

RJ

[boisking]

I'm about to head over to my "storage" and see if I can find that extra coil. It came off my 94, so no worries on compatibility for Bo.

My hero

[CraiginTX]

unless you have an oscilloscope to watch the signals... and provided you know what you are looking for on the signals...
RJ

On a (probably) unrelated note - anyone have a 'scope? I'm trying to chase the gremlins out of my newly rebuilt motor, and I'd like to verify that my injectors appear to be getting the correct pulses.

It's only running on 2 or 3 cylinders at the moment, but we seem to have fuel, air, and spark - so I guess we're down to quantity and timing of the elements now...

[Titus]

Are you sure the plug wires are connected correctly?

[CraiginTX]

Are you sure the plug wires are connected correctly?

If the question was for me - yes. I've even tried swapping wires with a known good set - though my Magnecores are relatively new. I've tried swapping 1&4 wires at the coil, as #1 runs great, 4 not all.

I'll start a new thread with the gory details...

[boisking]

Well, Adam's coil was not compatible. It was newer than he thought. I also had a cold ride to work today, since the car wouldn't start. I am ready for some ideas. Tests?

[boisking]

Car was running great for a few days, but decided not to start after work today. Of course, after testing for spark (none) and diconnecting/reconnecting connectors, she started. Contact surfaces in the connectors looked good to me. Wiring harness has no areas that I have found where anything is worn through. I am wondering if my wire shaking and connector adjusting revealed the problem or if it is coincidence.

[channelmaniac]

Car was running great for a few days, but decided not to start after work today. Of course, after testing for spark (none) and diconnecting/reconnecting connectors, she started. Contact surfaces in the connectors looked good to me. Wiring harness has no areas that I have found where anything is worn through. I am wondering if my wire shaking and connector adjusting revealed the problem or if it is coincidence.

NEED MORE INFO!

What connectors?

[boisking]

NEED MORE INFO!

What connectors?

Conectors for CAS and coils. Also, based on a tip from trackdog, I messed with the o2 sensor wires (Gary says a shorted o2 sensor wire has caused his car to cut spark, by shorting out the ignition/engine control fuse). None of the wires were loose or decaying, or anything like that. The copper contact points of the connectors were not corroded. Almost shiny, even. I also removed a small portion of the black stuff that bundles the wiring harness to the CAS and verified that the wire casing is still pliable. I am assuming that it is coincidence, with the car starting after messing with wires. I bet that there is a part going bad (still guessing CAS or coil).

[boisking]

Well, today my intermittent problem reared its ugly head again. This time, the symptoms were more severe. After work, It wouldn't start...nothing new. I have a trunk full of tools because of this problem. I get the car to start by just unplugging various wires, shaking the harness in various places, and cycling the ignition switch from OFF to RUN, not start, vigorously. There was no scientific method to this. I don't even remember what I did. I got approximately the distance of 2 blocks from my workplace (on 190 service road) and it stalled while driving. This is the first time I have experienced this. I get out and repeat the earlier "fix" method...and it starts again. I am planning on meeting the guys in McKinney for a movie, so I go east to 75, then north on central. As I approach Allen (just before Bethany ST), she stalls again. I coast across three lanes of traffic, across a bridge, and lose momentum 30 yards before the exit ramp. I am now sitting still on the shoulder of Central Expressway at 230-245 in the afternoon. Pretty heavy traffic traveling 65-75 MPH. "I like my odds" I think to myself as I hop over the passenger door and walk to the front of my car to try to repeat the SWAG fix aforementioned. No workie. I call for backup after 20 minutes of tinkering (I wanted to tinker anywhere except there). My brother, of course, is up to the door sills of his jeep in muddy water, and had to quit having fun to help me out. 40 minutes later, he arrives and pulls me to the nearest parking lot. Out come the tools. It is time to get down to the nitty-gritty. I start pulling everything out to inspect. All the plugs in the general area of the coil/cas are pulled and reinstalled. I apply my test light to all the connectors to make sure there is power coming out of the ECM. Good power signal, no start. I pull out the CAS, then disassemble it. I accidentally bend the little star thingy inside it, then bend it back. Then, I notice something that reminded me of Gary. The o2 sensor wires he had mentioned to me received another look. One was seperated. I swear it was not seperated when I pulled and shook on the wires back at work. It must have been barely hanging on by a single strand or something. I reassemble and reinstall the CAS, splice a new section of wire into the o2 sensor pigtail, and reinstall the wiring harness (I had begun to remove the engine harness from the rear of the head for more detailed inspection). It is running again......for now. My CAS currently has no rear cover on it (partial re-assembly for testing purposes). My timing is guestimated at somewhere between 0 and 20 degrees BTDC. I am just going to drive it and see if this problem reappears, but I hope that fixed it. I can handle looking dumb for not finding a broken wire sooner, if it saves me a few hundred bones in parts. Sorry for the long story. Bean, I assume you changed my signature for me. I like it, so I'll leave it alone.