anesthes

iTrader: (12)

I feel like a newbie. This just started happening. (TBI)

Driving, once and a while would set code 43. Scanned it, verrified about 4 times.

Yesterday, started it up sputtered and died. Only way to keep it running was
a clear flood (pedal to floor while cranking). It fired, ran rough, stumbled, check engine light came on, and then it was fine. Drove ok with light on solid.
Same code 43.

So I changed the ESC module since I had one on the shelf.
Same thing.

I figured I'd do a tune up, so I changed the distributor (had one on the shelf in likenew condition) cap, rotor, plug wires, and plugs.

Unplugged EST, set timing and ran GREAT!

Disconnected battery, plugged in est, reconnected and - same thing hard start and ran like CRAP. wtf I say.

Unplugged est, starts right up. repeat over and over. It runs GREAT with the est off.

Now. I've had vehicles with the knock sensor UNPLUGGED and it never did this. The next step troubleshooting chart wise is to replace the knock sensor, but jeez, has ANYONE ever seen a condition like this!?

Oh, I tried a spare ECM too I had on the shelf (I have a big shop), and that didn't do a thing either.

I'll replace the KS today I guess, and if that doesn't fix it I guess I'll start OHMing out the harness. It can't be mechanical because it runs and drives AMAZING with est unplugged.

-- Joe

jwscab

so by EST you mean the single wire connector to set timing? If so, that means the ecm is not controlling the spark advance properly when connected. when unplugged, it's running the static advance built into the igntion module.

either the ecm is seeing an invalid knock and dropping timing, or the distributor ref signal is not getting to the ecm, or the est signal is not getting back to the module. since it runs, I would say that the ref signal is definitely working, otherwise, you would get no injector firing.

you can narrow it down by unplugging the esc module completely. if that helps, it's either the power to the esc, the knock wire or sensor, or the output wire is grounded.

if not, i would investigate the est signal back to the module.

anesthes

iTrader: (12)

Thanks for the reply. Thats pretty much what the alldata troubleshoot charts are telling me, but I wanted to post here to see if someone has had the same symptoms. I'll ohm some stuff out tonight and see if it isn't the knock sensor.

Thanks for the reply!

-- Joe

RFmaster

Joe

Check spark plug wires - make sure that you do not have spark plug wire running in parallel to EST wire. It is possible that a leaky spark plug wire is coupling spark energy onto the EST wire and that in turn confuses EST module (spurious pulse). Take a look at your timing with a timing light with EST connected and disconnected. If there is a lot of false flashes that may confirm above suspicion. Code 43 is set when KS voltage is above 4.8 volts or below .64 volts for at least 10 seconds.

Code 43 Possible causes: 1) Open or shorted knock sensor
2) Loose knock sensor
3) Excessive internal engine noise

4) Intermittent open in the EST line to the ignition module (or EMI from spark plug wires)



//RF

NowTheBadNews

iTrader: (3)

43 can also be triggered by a bad magnetic pickup coil in the distributor. Mine did and did pretty much what your describing. But mine would sometimes feel like it was running on 6 cylinders. But it also did that foot to the floor starting because without doing it car would crank over and never seem to want to start.

anesthes

iTrader: (12)

The problem was a flaky CTS sensor. Didn't trip a CTS code, but read so awfully strange that the ECM was dumping varried amounts of fuel and spark, then causing some pretty hairy knock codes.

New CTS sensor and it was fine. Then it went on craigslist, and was sold.

-- Joe