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Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 6953
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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2004 Montero Sport - Initial maint.: Rough idle, oil leaks,

Customer Question

2004 Montero Sport - Initial maint.: Rough idle, oil leaks, A/C not working well, runs out pretty good with good power but after driving & engine heat up good it will not start back up until cool off a lot.
Troubleshooting: Oil leaks around valve cover gaskets, spark plug holes were full of oil up over the boots, caused a light misfire
Repair: replaced valve cover gaskets & due to mileage also replaced plugs & wires while top was open
Troubleshooting: when vehicle was not starting I found we had no spark, no signal at coil, no signal at ignitor, no rpm signal, finally found the crank sensor not working after runtime & heat up but after cooling for a time it would begin working, no codes
Repair: replaced crank sensor & while front opened up inspected timing belt, found many cracks close together in belt & it was still the original belt so it was replaced also
Troubleshooting: A/C was little low on Freon, small charge & seemed to be working well. Drove between 10-15 miles each day for 2 days testing transmission, steering, & running issues after all repairs. Runs very well, good idle, still ok on power but felt little hesitant.
Repair: changed fuel filter & pump
Troubleshooting: drove 1 more day approx. 20 miles off & on, runs great, great power, A/C great, start & stop great, All is good.
Gave back to Todd & he drove 1 mile to gas station & it would not start back up after shut off.
Troubleshooting: will not start even after cooling off, found no spark, no rpm signal, no communication with OBDII scan tool, vehicle equipped with immobilizer but all my research found it only affects the fuel pulse to inhibit starting, cannot get communication with pcm, not even a service engine/check engine lamp check when turn key to on position
Repair: replaced pcm
Troubleshooting: turn the key on & we have all communication with scan tool but no rpm signal, no spark, no codes, found the newly installed aftermarket cranksensor not working, also found cam sensor not totally reliable with output (seems to work & then quit, work again & quit)
Repair: replaced crank sensor with o.e.m. & cam sensor
Troubleshooting: finding no spark, no signal for spark before the ignitor, no codes
Repair: ?????? cannot find another source to go to, I do have pulsing voltage signals in range from the cam & crank sensors when I apply 12 volts & turn engine, also verified 12 volts on harness & power at ignitor. ??????
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.

You are right about the immobilizer... it will only inhibit the injector ground signal, though with excessive attempts to start (think 30-40 times etc) it will shut down the crank position sensor which will result in no RPM and no spark.

So with that all said... do you have RPM signal via scan tool while cranking now? Am I correct in understanding that both the cam and crank sensor were both replaced with genuine units purchased personally from a Mitsubishi dealer (not ones bought from OReilly or similar but sworn that they were OE)?

Customer: replied 1 year ago.
no rpm signal via scan tool while cranking... crank sensor is oe... but cam sensor is Oreilly
Customer: replied 1 year ago.
original cranksensor failed...but getting signal when replaced with oe
Expert:  Doug replied 1 year ago.


If you put the original cam sensor back in what happens?
Did anything noteworthy happen regarding the key?

Customer: replied 1 year ago.
no change
Expert:  Doug replied 1 year ago.


When reading the data list on a scan tool, what does it read for ignition advance while cranking? Injector timing?
We have verified all three coils are not firing, not just two that are not firing right?

I apologize in advance if there are delays coming up, our network is getting rebooted in a few minutes.

Customer: replied 1 year ago.
a. in the wiring harness to the coil, all three coils do not have a pulse.
b. i will have to get back with you sometime this weekend with the readings for ignition advance while cranking and injector timing.
todd c.
Expert:  Doug replied 1 year ago.

No problem Todd.
When you get a chance to check that out, if you have the ability I would like to check the low voltage pulse going into the PTU as well... it is the first three wires on the six pin connector (the other three are 12V, 5V, ground, then the three pin connector is ground output of course). I'd like to see what the exact voltages are while cranking on those three input wires from the ecu to the PTU).
I will be in off and on throughout the weekend, we can pick up whenever you are ready.

Customer: replied 1 year ago.
k thx
Expert:  Doug replied 1 year ago.

You're welcome