Youngmott

Hey I'm new to the forum basically I have a 1989 Chevrolet Camaro 305 tbi and while I was driving and made a turn I felt something different on how the car was driving come to find out the wire that runs to the ecm had cut in half leaving just the oxygen sensor other portion hanging, it only cut about a few inches , I've tried to replace the wire and crimp it with a heat shrink connector but since the problem happened the car runs good for about 30 minutes then cuts off but will crank right up, I'm wondering if I there is an open or short in the wire circuit since it was cut while the car was running, any suggestions?

ShiftyCapone

iTrader: (7)

Which portion of the wire was cut? On the sensor side or on the harness side? If it is in the harness you should be able to solder the two halves together and heat shrink it. Any idea how it was cut? Did it look deliberate or was it more of a tear from road debris?

Youngmott

Thx for the Message I think it was close to the steering column because when I turned I felt something rub against the column and then I seen it was cut while the car was running, was on the sensor side the O2 side was good but I still replaced it with another sense it might have shorted it out.

Schurkey

Huh? It's cut on the sensor side, but the O2 side is good?

Is it cut on the O2 Sensor side or the vehicle harness side of the sensor connector?

If the break in the wire(s) is near the steering column, it'd more-likely be the vehicle harness that's affected, not the sensor.

Youngmott

Yea I meant the O2 sensor wire wasn't affected because it wasn't cut , just the signal wire to the ecm, I still not sure where the O2 ground wire is, isn't it behind the drivers side cylinder head ? I'm pretty sure it shorted the O2 sensor signal wire because it will run good for about 30 mins then die intermittently but starts right back up

Schurkey

I'd have thought that you'd have a one-wire O2 sensor. There is no "O2 ground wire". Am I wrong?

ShiftyCapone

iTrader: (7)

You are correct. It is a single wire. I still don't know if he has found a damaged section of his engine harness yet or not. He found a "cut" but don't know if he found the other end. The OEM wiring should be free and clear of the steering shaft.

Youngmott

O no basically what it was I put a cable tie around it lol not realizing that it turns it was only the O2 sensor signal wire I did this after replacing the oxygen sensor z should of just left the wire where it was but jus didn't want it to move because of vibration sorry for the misunderstanding. When I discovered the wire it had the oxygen sensor connector part cut and was jus the stray wires on the ecm side I've tried crimping it with heat shrink connector after replacing the connector that was missing that connects to the oxygen sensor about 4 or times but the car still stalls after running for a while I'm guessing there's an open in the wire that's causing it to not give a good reading to the ecm

Youngmott

Anyone have any suggestions?

8t2 z-chev

something besides the O2 sensor wiring is causing the stalling-you need to find if you are losing fuel or spark-if the stall happens at idle ,watch the TBI spray with air cleaner lid off and see if fuel stops right before stall . The o2 sensor just fine tunes the fuel flow and the ECM switches to closed loop operation when o2 warms up and puts out voltage signal -if no o2 sensor volts after a couple min.CEL will light.

Youngmott

I just assume it's the signal wire because before it was cut it was running good not stalling at all

Schurkey

Connect a scan tool, verify EVERY sensor and computer output.

What is the fuel pressure?

How old are the usual tune-up items--distributor cap, rotor, plug wires, plugs? Inspect the PCV and EGR systems. Verify initial ignition timing, and electronic spark advance including the knock sensor.

Youngmott

Haven't checked those yet I just am like 90 percent sure it's between the wire to the ecm or ecm itself because it was running great before the wire was cut while driving and I noticed it like few minutes after driving definitely wasn't driving it longer than few minutes before i seen the damage

Youngmott

Hey I did a bit of troubleshooting and I'm getting ground voltage on almost all of my ground wires ecm ground had like .45 and sensor ground had about .50 any idea on why? I'm thinking when the o2 sensor was cut it might of short to ground I'm jus not sure how to see which one it is since they hard to get too behind the cylinder head

Schurkey

Clean BOTH ends of the negative battery cable? (Three ends, if it also bolts to the fender.)

Youngmott

Use electrical cleaner ? Didn't think it would have anything to do with that cable but I'll clean it

Schurkey

No. Remove both (all three?) ends, polish with Scotchbrite pads and/or a wire brush until all mating surfaces are shiny. Battery post(s) and cable end(s), cable end + fender, cable end + engine. Reattach firmly.

If you've still got half-a-volt on the ground cables, you probably have corroded cable under the insulation. Would then need to replace the cable. Around here, parts stores love to stock flimsy, crappy, undersized battery cables (6-gauge) when OEM is typically 4-gauge, and 2-gauge is kinda nice. Thicker than 2-gauge is unneeded, wasteful, and heavy.

Youngmott

O ok would that cause my car to run rich? I used multimeter to measure oxygen sensor voltage while car running it stays in high 7-900 millivolts but soon as I press gas it fluctuates up and down from 1-9 like it's supposed to

Youngmott

And with the ground having voltage that would cause an intermittent stalling? Because that's the main probably I had since the wire had been cut

Schurkey

Voltage on the ground cables can't be helping, but that's not the first thing that I'd think of for a rich idle and normal-fueling above idle; or for stalling.

Wild Guess: Leaking injector(s) causing a rich idle. Possibly a failing MAP or TPS sensor signal leading to over-fueling.

Connect a scan tool, verify ALL the sensors and computer outputs.
Verify fuel pressure.
Assure that all the usual tune-up items and procedures are good and correct.