SUV was running great but broke the timing belt

Tiny
ANONYMOUS
  • 1996 MITSUBISHI MONTERO
  • 120,000 MILES

SUV was running great but broke the timing belt. I did a valve job but when done is not firing on two cylinders (same coil). Have replaced everything -- coils, ignition controller, crank and cam sensors, and the computer. I run the problem down to the connection between the crank sensor and the computer. Two of the prongs have connectivity (blue light on tester), but the third (on the dead coil) is open (no blue light on tester). However, the wire color (black with red stripe) on the bad sensor lead does not appear on the computer harness -- there is no black with red stripe wire on the computer harnerss! How the heck does the wire color change from end to end through the wiring harness fron the sensor to the computer? Anyway, to troubleshoot further I need to know which computer pin goes to the crank sensor. Also, any other idea on what could cause the problem?

Monday, October 22nd, 2012 AT 10:53 PM

9 Replies

Tiny
RASMATAZ
  • MEMBER

-Anyway, to troubleshoot further I need to know which computer pin goes to the crank sensor.

See below for a 24 valve engine

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Monday, October 22nd, 2012 AT 11:04 PM
Tiny
MMEHRMAN
  • MEMBER

Thanks. I am not an expert and the one diagram provided is not enought for me to understand the situation. Unless the blocks on the top are the computer, the connection to the computer from the blk-red from the crank sensor is not shown. But the block on the top right (connection from blk-red on crank sensor) shows blk-red wires and the computer has none of them connected, so I'm figuring the blocks on the top are not the computer pins.

Can you tell me what the blocks at the top are, and where the blk/red from the crank sensor exiting the diagram to the left goes? Can we run the blk-red on crank sensor to the correct pin on the computer?

More importantly, do you have any idea what could cause two prongs of the crank sensor connector to show connectivity (blue light on tester), but the blk/red to be dead (no light on tester, no spark on two coils driven by that sensor signal). That is the bottom line -- what to do next.

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Tuesday, October 23rd, 2012 AT 2:07 PM
Tiny
RASMATAZ
  • MEMBER

What made you replace all those things over a broken timing belt-Shouldn't be nothing wrong w/the wires on the CPS-try checking the CPS resistances-as per the wiring diagram this is all I got-BTW is it a 24 or 12 valves

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Tuesday, October 23rd, 2012 AT 11:20 PM
Tiny
MMEHRMAN
  • MEMBER

It is a 24 valve 3.0 V6. The engine was running fine (quite well really) but overheated when it broke down (the temp on the inticator shot up just as the breakdown occurred). Once I put the rebuilt heads on and the engine back together, one of the coils (two cylinders) was not firing. Four cylinders were firing indicating that the timing was set right. So I began to trouble shoot the ignition problem. One thing after another did not solve the problem, so now everything in teh ignition circuit is new -- coils, computer, ignition module, crank and cam sensors. But the same problem still occurs -- one coil is dead. Swap the coils, same thing. When I pull off the crank sensor cap -- on the side going to the computer -- the two working leads show connectivity (blue light on the tester) but the non-functioning lead shows no connectivity (no blue light on the tester). That is where it stands now.

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Wednesday, October 24th, 2012 AT 4:13 PM
Tiny
RASMATAZ
  • MEMBER

Do you have a blue light on the black and red on the camshaft sensor?

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Wednesday, October 24th, 2012 AT 9:59 PM
Tiny
MMEHRMAN
  • MEMBER

Nope, blk/red is dead on cam and crank sensor leads. The other two leads show connectivity on both.

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Thursday, October 25th, 2012 AT 2:45 PM
Tiny
RASMATAZ
  • MEMBER

Check that wire back to the computer

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Thursday, October 25th, 2012 AT 10:42 PM
Tiny
MMEHRMAN
  • MEMBER

That is what I am trying to do. The wire goes into a harness within a corrugated cladding and presumably through the firewall to the computer in the passenger compartment. How do I go about checking it back to the computer? Can you tell me which computer pin that blk/red wire connects to?

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Sunday, October 28th, 2012 AT 8:53 PM
Tiny
RASMATAZ
  • MEMBER

Pin no.26

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Tuesday, October 30th, 2012 AT 12:11 AM

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