Hello All,

I have a 1992 240 wagon that dies when idling. I drove the car this morning to the marina and everything worked fine. When I started the car a few hours later to drive it home, it wouldn't stay started. It sputters and dies unless I keep the RPMs up with the gas pedal.

I drove it home this way (about 5 miles), and it seemed to run fine as long as I was moving and pressing the gas pedal. When I got home I checked the engine service codes. Pin 2 resulted in code 2-3-1 and pin 6 resulted in 2-1-4. These were only codes logged for each pin.

I found a page that lists the 2-1-4 as erratic RPMs from the RPM sensor, but I don't know if this is the cause or the just a symptom. Would the lambda sensor cause these symptoms (and also the 2-1-4)?

Any ideas?

Mark

 

With 2-1-4, most likely it is the crank position sensor which is mounted on the top of the transmission bell housing.

I would inspect the wires and clean up the connector first.

 

Thanks for the reply. I removed the sensor and cleaned both ends but it didn't fix the problem. The car wouldn't start at all while the sensor was off. I'm going to AutoZone this afternoon to pick up a new one for $50. I'll let you know if that does the trick.

Thanks again,

Mark

 

You might also try unplugging the air mass meter with the power off, and then trying to drive it that way - suggesting that the AMM is bad if it runs better.

 

Thanks once more for the advice. When I unplugged the AMM as you instructed, the car will stay started, though the idle is very rough. When I plug the AMM in and start the car, it will idle rough for a few seconds then die (as before).

Should I hold off on the new crank position sensor and instead replace the AMM?

Thanks,

Mark

 

So that points to the AMM - dies while plugged in, idles rough when unplugged (limp home mode). They are expensive new/rebuilt so I would look for one on ebay or at the junkyard.

Disconnect the battery before installing the new one since a new ECU "map" will need to be created, and codes cleared.

A good source for the Crank sensor is www.fcpgroton.com

 

One more thing, I checked the resistence between the second and fourth pin in the AMM. One way was about 10 ohm, the other (flipping the red and black multimeter leads) way was 1.5 ohm.

I also took a look at the price for an AMM. It makes me wish it had been the crank position sensor.

 

It sounds like you are measuring the resistance of the burn-off wire (white), so 10 ohms is OK.

The only real practical way to diagnose a AMM failure in the field is to swap in a known good unit, since the output voltage can vary by a small amount causing the car not to run.

Maybe someone can let you "barrow" one?