Possible Bad PCM
Thread Starter
CF Beginner
Joined: Aug 2018
Posts: 17
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Well yes and no.
The mechanic got it running, but as to how we have no idea. He froze the PCM to tighten the components back up, probed some wires and his helper turned the key and it started. After that, I went and picked it up, started and ran the engine several times over the course of the weekend, and drove it home. In total I put about 48 miles on it.
Then there was some bad winter weather on the following Monday, and on Tuesday I went out to start it and drive it down to the car wash to use the vacuum cleaners, and it wouldn't start just like before.
Since the tachometer isn't moving at all while turning over, that means that the Cam sensor is having poor to no connection again, since the tachometer reads the CMP, and the entire timing process is determined by it, so if it doesn't have a connection, it's not going to start no matter what.
We think the solution is to replace the whole circuit (almost) altogether. I've gotten a new harness connector for the sensor, and new wire so I can replace the two signal wires that go straight from the sensor to the PCM. There is a third wire, but it's a power wire that also runs to many of the different parts of the engine, which all work, so we don't suspect it. Just gotta hope for a warmer day soon so we can do it.
The mechanic got it running, but as to how we have no idea. He froze the PCM to tighten the components back up, probed some wires and his helper turned the key and it started. After that, I went and picked it up, started and ran the engine several times over the course of the weekend, and drove it home. In total I put about 48 miles on it.
Then there was some bad winter weather on the following Monday, and on Tuesday I went out to start it and drive it down to the car wash to use the vacuum cleaners, and it wouldn't start just like before.
Since the tachometer isn't moving at all while turning over, that means that the Cam sensor is having poor to no connection again, since the tachometer reads the CMP, and the entire timing process is determined by it, so if it doesn't have a connection, it's not going to start no matter what.
We think the solution is to replace the whole circuit (almost) altogether. I've gotten a new harness connector for the sensor, and new wire so I can replace the two signal wires that go straight from the sensor to the PCM. There is a third wire, but it's a power wire that also runs to many of the different parts of the engine, which all work, so we don't suspect it. Just gotta hope for a warmer day soon so we can do it.
CF Active Member
Joined: Feb 2018
Posts: 185
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From: Currently the Candian Gander is wintering over in New York.
Wow, good and bad news. The cold weather and whatever humidity got in there and likely caused an open wiring connection.
You could use a meter and check for excessive resistance.
At this point, I think you may have found the culprit in the connector. Maybe you could spray it out with electrical contact cleaner You might look at it close to see if it has sprouted green fur, a sure sign of corrosion from copper.
You could use a meter and check for excessive resistance.
At this point, I think you may have found the culprit in the connector. Maybe you could spray it out with electrical contact cleaner You might look at it close to see if it has sprouted green fur, a sure sign of corrosion from copper.
Thread Starter
CF Beginner
Joined: Aug 2018
Posts: 17
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Hey quick update, we got it running again without replacing anything. We literally just unplugged the corresponding harness plugs from the PCM, plugged them back in, and it started. We're pretty sure now that the wires are good, and that if there really is an issue it's with the plug.