Is it safe to remove the coolant sensor and run without it?

1990 VW Cabriolet, Digifant, runs 3 hours at highway speed, and gets caught in city rush hour traffic. Stop and go, slow moving. Engine suddenly loses power, will not go above 2000 rpm. Black puffs of smoke at tailpipe, will not rev up, either in gear, or out of gear. Idle drops to 650rpm, and is choppy and rough. Mixture is too rich, too much fuel.

I let the car sit for 20 minutes, and it is fine, until it gets to stop and go traffic again, then symptoms repeat. Car runs fine at highway speed though.

This car did this 3 years ago, but symptoms began at highway speed, not when arriving hot into city speeds. o2 sensor is fairly new, so might not be the problem.

Symptoms stop when Coolant Temperature Sensor is unplugged. (Small blue clip at front of engine). It could be either the sensor, the wire from the sensor to the computer, or the computer itself.

Is it safe to run with this sensor unplugged?

I am told the sensor should only operate when engine is cold, will increase fuel to mixture, and open the thermostat.

I need to go 1,000 miles with this car, can I unplug it and make the run?

I had to circle 4 hours back from Dallas today, back to E Texas, and I really really need to take this car 1,000 miles to Denver.

Hubby is diagnostic mechanic, but has no access to test equipment peculiar to VW, so cannot pull an error code up.

Have you ever had this glitch?

Reply to
Dresden
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Actually, after reading your post, I am now inclined to think it may indeed be the computer, or one of the boards in it, as the failure was massive, yet subsided as quickly as it came on, after I let the car rest and cool for

Reply to
Dresden

None that I know of. it still might end up telling the engine to run kinda rich though.

I do know in my A2 repair manual it says something about not unplugging it while the engine is running (or maybe it's while the radiator fan is running...can't remember for sure) so just make sure you do the hook/unhook when the ignition is off and the fans aren't on.

Reply to
Matt B.

Like someone else mentioned, replace the switch for under $20.

I'd guess the O2 sensor even though it was recently replaced. Check the splices to make sure they're all good. It doesn't sound like a bad temperature switch. That car will run fine without the blue temperature sensor connected, however, it may be hard to start (especially when cold :)

Reply to
Darryl

I have the EXACT same problem you are having only the temp sensor was replaced (a couple of times) and I still have the same problem. We have looked at all the wiring, the computer, the mass air flow meter, everything. My mechanic even consulted some Bosch technicians and still nothing.

I have been running my car with the temp sensor unplug for a month or so now. I think you'll be OK.

But if anyone here has any suggestions I would greatly appreciate it!!

Reply to
sonodude

Reply to
Dresden

Ditto, Ditto. When it was first doing it, I would stop and turn off the engine for 5 minutes and it would be fine for a few days. Then it would do it again. Then it go so after stopping and turning off, it would be fine for the rest of the day. Note that it would only first happen in the morning (ie subsequesnt start ups during the day were fine).

Now, it just happens all the time. After about 1 minute after start-up, every time, it goes into that infernal chugging mode. So I just leave the temp sensor unplugged.

For what its worth, I highly doubt its the computer. We tried that on mine and no dice.

Sill looking for a solution.

I'm so depsarate, that I might actually go to a dealer! Yikes!

Reply to
sonodude
*feels an instant sense of bonding to Sonodude*
Reply to
Dresden

Same problem here. Traced it down to O2 sensor. 90 JettaGL 1.8 Dig2

Reply to
<randypolk

How did you go about tracing it down? Trial and error?

I had the O2 sensor replaced in February 2002. Can it go bad in one years time?

Reply to
sonodude

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