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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8622
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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I have a 2001 montero ltd...been having ignition problems

Customer Question

I have a 2001 montero ltd...been having ignition problems caused by battery being installed in reverse. Ran fine prior, just needed a good tuneup. Upon correcting this mistake, the engine cranks but no start. I did many tests w multimeter and it pointed to either crank or cam sensor, igniter or pcm. I installed new coils (as I was going to do that anyway w tuneup) and still no start. I have power to coils but no spark even after switching out igniter for another used one. Starts to sputter like it wants to start. So my thinking is that either/or crank or cam sensor not communicating w pcm. My first question is...can crank sensor be changed w/o removing timing belt?
Submitted: 2 years ago.
Category: Mitsubishi
Expert:  Doug replied 2 years ago.

Hi,

The crank sensor can be changed without changing the timing belt... but it is exactly as much work regardless. All of the front covers have to come off to get to the sensor, and at that point the only thing keeping you from changing the belt is just removing the tensioner on the belt.

What I would do here before getting that involved is first check your voltages on the crank sensor harness. You should have 12V, 5V and ground on the connector while unplugged and the key is on. If you are missing voltage on either wire, double check your fuses.
If the voltages are present, then reconnect the crank sensor and back-probe the 5V wire then manually rotate the engine clockwise and observe the voltage reading. You should see it change (roughly) 5v-0v-5v-0v etc. If it does not, the crank sensor is bad (Same series of tests can be applied to the cam sensor).

If you have normal operation, I would be re-checking all of your fuses and fusible links. Normally when a reverse polarity event occurs you will end up taking out multiple fuses and the larger fusible links. It is highly likely you have either a fuse that blew that was not caught yet (either under hood or in dash) or one of the larger fusible links under hood popped and is just barely making contact etc. It is extremely rare for a reverse polarity event to go beyond that unless it was left hooked up for a while that way (not just quick connection and correction).