1999 Montero Crank Position Sensor Failure

[Taylor1]

I think the crank position sensor failed on my Montero. Any confirming theories or suggestions are appreciated.

Symptoms started when I split the small coolant hose in center of engine above the timing cover leaking coolant down the front. I wad close to home so, no overheating based on the gauge.

New aftermarket crank sensor was put on with timing belt, water pump, cam and valve stem seals about 7k miles ago. Preventive maintenance I thought...

So two weeks later, cold start is normal, but after 5 minutes idling or driving up to operating temp it will cut off. It may restart once, but after 10 minutes it will cut off and not restart.

ECM generates P0335 crankshaft position sensor circuit A.

I testing and retested all harness connections before tearing it down today. Swapped crank sensor with the OEM Mitsubishi (part 240k miles if original) watching voltages generated on the blue signal wire as the taller wheel tab passes into sensor turning engine by hand. Consistent 4.9 or 5 volts with the OEM sensor..
Sometimes 4.8 sometimes 2 volts or less with the aftermarket sensor.

Random failure with poor parts or failure related to the coolant exposure/overheating?

Any ideas?

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[PacS14]

I think the crank position sensor failed on my Montero. Any confirming theories or suggestions are appreciated.

Symptoms started when I split the small coolant hose in center of engine above the timing cover leaking coolant down the front. I wad close to home so, no overheating based on the gauge.

New aftermarket crank sensor was put on with timing belt, water pump, cam and valve stem seals about 7k miles ago. Preventive maintenance I thought...

So two weeks later, cold start is normal, but after 5 minutes idling or driving up to operating temp it will cut off. It may restart once, but after 10 minutes it will cut off and not restart.

ECM generates P0335 crankshaft position sensor circuit A.

I testing and retested all harness connections before tearing it down today. Swapped crank sensor with the OEM Mitsubishi (part 240k miles if original) watching voltages generated on the blue signal wire as the taller wheel tab passes into sensor turning engine by hand. Consistent 4.9 or 5 volts with the OEM sensor..
Sometimes 4.8 sometimes 2 volts or less with the aftermarket sensor.

Random failure with poor parts or failure related to the coolant exposure/overheating?

Any ideas?

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Aftermarket parts are usually prone to fail either right away or have a short life, so whatever it was, as long as you are able to do the proper repair/replace, you are already ahead. Good luck!

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[Salonika]

Crank sensor is a big job, so I'd only use Mitsu parts there........cam sensor however is way easier, so you can roll the dice there....imo.

 

[Taylor1]

Any comments on SMP Wells crank position sensors listed in the parts list sticky being equivalent?

Ill go back with Mitsubishi. All in favor to put Mitsubishi part number in the sticky ... I'll post there as well.

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[nckwltn]

Crank sensor is a big job, so I'd only use Mitsu parts there........cam sensor however is way easier, so you can roll the dice there....imo.

You can replace the CAM sensor in the 99 by removing the timing belt cover on the driver's side. It's a little fiddly, but not too difficult.



Also, when my crank/cam sensors were out, I read online (and confirmed) that you can mash the gas pedal to the floor and that will do some kind of computer override, and the engine will start... if the sensors are out, it will run like crap, but run long enough to trigger the check engine light and let you read the code.

 

[Taylor1]

nckwltn- you mean the cam position sensor behind the drivers timing cover?



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[jlocster]

For what it's worth, I've been running the SMP INTERMOTOR PC191 Sensor, Crankshaft Position from the sticky for about 15,000 miles with no problem. That said, if in doubt, go OEM.

 

[Salonika]

You can replace the crank sensor in the 99 by removing the timing belt cover on the driver's side. It's a little fiddly, but not too difficult.



Also, when my crank/cam sensors were out, I read online (and confirmed) that you can mash the gas pedal to the floor and that will do some kind of computer override, and the engine will start... if the sensors are out, it will run like crap, but run long enough to trigger the check engine light and let you read the code.

No idea how this works since the crank and cam sensors are the only way for the computer to know engine timing. If they are out, the ignition wouldn’t be able to know when to spark, injectors when to open, etc.....when my crank sensor was failing, when it acted up I would have no spark. Seems like there would be a big risk of ignition at the wrong time if the computer started adding fuel and spark without knowing timing?

 

[nckwltn]

nckwltn- you mean the cam position sensor behind the drivers timing cover?

YES, thank you for pointing that out..... Edited my post

 

[nckwltn]

No idea how this works since the crank and cam sensors are the only way for the computer to know engine timing. If they are out, the ignition wouldn’t be able to know when to spark, injectors when to open, etc.....when my crank sensor was failing, when it acted up I would have no spark. Seems like there would be a big risk of ignition at the wrong time if the computer started adding fuel and spark without knowing timing?

I had a bad crank sensor, and car would start intermittently and run really badly..... pegging the pedal to the floor would get it to every time.... thinking that it might over ride the computer to some default setting and ignores the sensor feedback.

It could also be that I'm making a connection between two unrelated things

 

[Taylor1]

The Montero is back on The road. The new Mitsubishi crank position sensor solved the problem.

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[MrGalantguy]

I was going to say...when is comes to sensors, try to stay with OEM Mitsubishi.

Glad to see your Montero is back up Taylor1

 

[bikerjosh]

Replaced mine during the winter, then last weekend during a trip. Hopped back in to start and popped the P0335 code. Voltage checked out. Eventually got it running but not sure how. and no I didn't use a OEM crank sensor

 

[Taylor1]

Replaced mine during the winter, then last weekend during a trip. Hopped back in to start and popped the P0335 code. Voltage checked out. Eventually got it running but not sure how. and no I didn't use a OEM crank sensor

Frustrating stuff. Simulate and test all possible conditions in the driveway to avoid the suprise failure and tow truck fun I had at midnight.

Mine was fine from a cold start. After failing to restart one evening, I could clear the same code and go the next morning... for about 10 minutes.

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[bikerjosh]

Well, can't ignore the P0335 code, popped up twice in less than a week, first time managed to get the truck to start ran really rough for about 5 seconds then smoothed out; second time it happened couldn't get it started and left it. Came back next day w/full bag of tools hopped in and it started w/o popping the hood. Ahhhhhhhhhhhh! Drove it home and parked it. Need to buy another Crank Pos Sensor, not hard to replace just time consuming especially if it doesn't last that long. Going to see how much more the OEM sensor is, just don't want to tear this apart again until the timing belt needs to be done in like 50k.