93 Caravan Computer problem

I'm hoping someone has heard of this problem. Drove my '93 caravan, 3.3, 4sp auto, 200K miles through a puddle and it started misfiring. (I thought time for new wires). Next day she fired up fine and drove fine for a week. And then it rained. She died after going through a puddle. I believe the speedo jumped from 30 to 60MPH then bounced down to 0, then back to normal (it does not have a speed sensor, I think this is from the computer putting it in neutral while dieing). Then the check engine light blinks once, then its dead. Cranks but won't start. Went ahead and replace the wires and coil. Engine code shows code 42, Auto Shut Down. Diagnostics computer shows crank senor good, cam sensor good, Auto shut down "ON". Computer won't reset. Disconnect battery, won't reset. Disconnect computer, won't reset. Disconnect/connect crank sensor, car fires one cylinder then "ASD". Replace both crank and cam sensors with known good sensors, fires once, then ASD. Replace the computer with a known good one. Car starts and runs. Yea! Runs fine for 19 miles and I hit a puddle. ASD!!!!!!! Disconnect and reconnect good computer, nothing. disconnect/connect sensors, fires once then nothing. Take good computer out, put bad computer in, it starts. (@#$%) Idles fine, revs up fine. put it in gear, idles fine, hit the gas it starts bucking then ASD (more @#$%).

Three questions.

  1. Has anyone heard of this? Any guesses?
  2. Could it be the tranny wiring harness is getting wet? If so, does anyone know the wire colors of the crank sensor?
  3. Right after it died the last time, I heard a very faint whinny alarm sound coming out from between the battery and the tranny. It was not coming from the computer, the tranny computer, nor the shift control module on the tranny. It stopped when I turn the van off and back on. Does anyone know what this alarm is?

Thanks to all who answer.

Reply to
OrigDirtyOldMan
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The common element is water. You have an electrical problem. This is NOT a computer problelm. Water is shorting something out.

In days gone by I have had water splashing on bad high-voltage ignition components like plug wires and shorting out the system. In my older cars, it caused rough running first, and then it would stall under load.

So start with the simple stuff. remove and inspect your plug wires one at a time. But if these are the original wires... time for a change.

Otherwise, start looking at wires and connectors. Look for worn insulation and corroded contacts.

Good luck. Sometimes these are hard to f>I'm hoping someone has heard of this problem.

Reply to
NewMan

In my msg, I had said that I replaced the plug wires and coil. This is not a ignition problem. I can hot wire the coil. The computer is not sending the fire referance signal to the coil, it has also turned off the fuel pump (solved with either or hot wiring the relay). This is because the "COMPUTER" has tripped the "AUTOMATIC SHUT DOWN" relay (code 42). The computer believes the engine is unsafe to start. The purpose of the code is to shut the engine down if the timing belt breaks. The 3.3 uses a chain and I can watch it through the cam sensor hole and it is fine. I've also found messages from others with the ASD / fire once after reset problem. However the fix was never posted. In their msgs they don't mention water. There were some referances to the oxygen sensor. But the manuals say the ASD turns off the O2 heater not the other way around. I do not think the problem is the water, but the coldness of the water is pissing something off.

I took all the eng> The common element is water. You have an electrical problem. This is

Reply to
origdirtyoldman

P.S. The computer will also trip the ASD if the fuel presure drops. I have ran a hot lead to the ASD causing it to engage which allows the fuel pump to energize. The pump runs and has good volume. I have 3/4 tank of gas. The hot lead also energizes the coil. I have good 12 volts and ground on the coil. Just not the referance signal.

Reply to
origdirtyoldman

The "$15,000 Snap-On" diagnostic tool tells you what it sees. Common sense is supposed to be supplied by the person "operating" the tool.

How many times does the PCM have to tell you that it's detected a problem in the ASD circuits before you check those circuits out?

Reply to
bllsht

Right off the bat.... replace the ASD relay...... My van did a similar thing.... ASD relay had gotten water in it and corroded the contacts.

Now, I dont know if the 93 has the same layout as the 94 (which is what I have), and the ASD is in the power distribution/relay block... unbolt it and remove the bottom and check the contacts and wires. I checked this area on my van, and found a few wires backing out of their terminals.

Have you cleaned the contacts in the harness that plugs into the PCM? Try that and see if it helps.

The Snap-On scanner (weither it be a Solus, Modus, or the MT2500) can only tell you what the PCM of the van tells it.

Reply to
Homer Simpson

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