2002 Montero Sport Rough Running, No Codes!!
 

About to pull my hair out.
I just completed an engine rebuild. Up until Sunday, aside from some minor issues, it was running fine. Sunday, however, my son calls me and says that it died on him. It restarted once, then died again for good. Camshaft and Crankshaft codes. Got the covers off and it had jumped time. Screw it! I replace with ANOTHER new belt and new concentric pulley. Tensoined it so the pin would slip out of the NEW hydraulic tensioner. Got everything put back together, and it's running terribly. The kicker is that it is throwing no codes.
Full disclosure here. While pulling things apart, I was lazy and did not disconnect the battery. When I pulled the alternator, it slipped out of my hands and did some "welding" on the motor mount, to the point that the 100A fuseable link for the alternator fried. Replaced that, and everything works, except that it runs so bad. Seeing as I am throwing no codes, I was afraid that I might have fried the PCM, however, I am getting full live data. The only anomaly I can see in live data is that the #1 fuel bank shows OPEN, and the ST fuel trim seems out of whack. (I had fuel injectors on hand, so I replaced them precautionary). So to confirm the OBD was operating, I pulled the connector to the 3/6 coil pack. It shut down, and I got the P0300 random misfire. So I am confident that, at least from a I/M standpoint, that the PCM is good. I removed and inspected the PCM. There are no burn marks or evidence of shorts.
I am at a loss. Is it POSSIBLE to time the engine 180 out?? As long as all three marks are lined up, the timing is correct, right? I have tried to rotate the crank through without having the belt on, but it stops at about 3/4 rotation. Seeing as this is an interference type engine, I can't fathom HOW it could be 180 out. I am going to pull the plenum this week and do a full compression check so HOPEFULLY rule out bent valves. I just can't figure out how it is running so rough without setting any codes. Has anyone seen this? Any words of wisdom would be appreciated.

You can't be 180 off the timing. This is because there is no timing mark at 180 rotation on the crank shaft pulley. You could time it one full rotation of crank shaft off compared to where you started a the camshafts, but that would not make any difference because the cylinders would be in the same place. How much did the timing belt jumped (how many teeth off)?. If it was just one or two teeth off, you should be OK, but if it was more, then valve damage is possible. Do run the compression tests to see if all work well in that area. Make sure to do a "dry" and "wet" compression. This will tell you if you are having a valve issues if you encounter low compression.

Thanks Hunter. Maybe 3-4 teeth. That's what throws me. He was sitting at idle with no stress on the engine. I could understand it jumping if he were accelerating hard. Would a bad valve throw a code?

You could potentially bend a valve being 4 teeth off timing. The fact that the engine was at idle might work in your favor and not result in damage. Run a compression tests to see what you got going there. Like I said, if you have low compression and it is not "corrected' by wet compression - you got a valve not seating properly (possibly got bent).
You might know this, but here it is anyway: "dry" compression test is when you just perform a straight forward test on all cylinders. The "wet" compression is done by adding a teaspoon of engine oil to each cylinder prior to testing. You always want to do "dry" test first, then a "wet" one, not the other way around. The purpose of oil is to seal any leaks due to worn out piston rings. If you have low compression with both tests - you got valve problems. If only dry compression is bad - you got issues with rings.

Some folks also say to remove all the spark plugs and test one cylinder at a time for compression pressure then the dry/wet as Hunter described.

My timing belt broke on me while driving on the freeway. It was a bit tricky getting the timing right on it. Mine wouldn't turn over at all initially until I got back into it and fixed the timing. I replaced the tensioner, water pump and both belts. My alternator went out almost immediately after installing everything so then had to change that out too. Runs like a clock now.. I guess what I'm saying is that I was driving on the freeway when my timing belt broke and I didn't bend any valves so don't I doubt that is your issue. Even though everyone was telling me I most likely bent valves and should just junk the car, they couldn't have been more wrong.

Glad you were able to get your car fixed. You should NEVER junk a car, unless it is totally not fixable. Replacing couple of bent valves is not a big deal. Its amazing how differently some situations play out - in your case TB fail at highway speed... All that it took was to replace with new TB. At another time the same scenario would play differently. Really glad it worked out in your case.

Yeah mine is a 2002 Mitsubishi Montero Sport Xls. I have over 2 hundred thousand miles on it. Never had any problems until that belt broke like that. It'd been making a ticking sound at idle a little while prior. I had a couple so called pro mechanics tell me it was rod knock and to junk car. Other so called professional mechanics say it was damaged lifters. It actually turned out to be my belt tensioner. I could have prevented the timing belt breaking while driving if I'd replaced that. Live and learn