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Discussion Starter #1
Hi all,

I'm dealing with a rough idle and I can really use some help and advice.

To begin with, my Evo is a 2010 SE and it's completely stock. I’m logging with Evoscan and a tactrix 2.0 cable using the the MUT III ECU setting.

The issue started when I was checking lash adjuster clearances and I managed to drop one of the valve cover bolts onto the valve tappet on the exhaust side and I didn’t notice. I checked the clearances on half of the engine and when I turned the engine over to check the other half, I turned it pretty hard by hand without thinking. The stray bolt marred the side of one of the cam lobes and basically bent at 90 degree angle, but didn’t seem to do any real damage to anything else. Just glad they are aluminum. The scratch on the cam lobe was above any contact points, so it seemed like everything was ok. So, I put everything back together.

When I started the car it had a rough idle with a lot of popping in the exhaust. It basically sounds like a Harley at idle. I suspect valve overlap, or something like that. The RPMs fluctuate between 1.5k and 1.25k, periodically dipping down to 750 at which point it sounds like it comes close to stalling before jumping back up. It throws a P0017 CEL which is an “Crankshaft/camshaft (exhaust) position sensor phase problem". So, I figure I did more damage than I had originally thought, so I replaced the cam sensor which didn’t help. I also noticed that unplugging the exhaust sensor didn’t make any difference. Running down the list of problems associated with this code, I’ve checked the timing belt tension and position and that looked fine. Pulled out the oil control solenoid and bench tested it. That checked out. Changed the oil, partly just to make sure there were no metal flakes in it. That was fine. Running down the list, the next thing to check out is the VVT sprocket and the crankshaft position sensor. I doubt it’s the crank sensor and before I remove the cam shaft to check the VVT, I wanted to compare my VVT values at idle to a good set. I did notice that the exhaust side fluctuates at idle along with the movement in RPMs, so I’d like to know what’s going on there.

I attached my log which includes the VVT readings and a few other measurements. Two things I noticed were that the VVT readings oscillated between 51 and 57 (degrees) for the most part. The reading would drop into the high 40s after a little while, 15 seconds or so, and then move up into the low 60s before settling down again. This seems to track with fluctuations in the RPMs as well. When I eased into the throttle, it would drop to -14, with a drop in RPM until I gave it more throttle. Then it comes back up to normal readings and the RPM rises. I don’t know if this is normal or not. The drop in RPM certainly isn’t. This is where a healthy idle would be nice to see. The other oddity I saw was that the exhaust VVT tracked perfectly with the intake VVT. Maybe this is normal under no load, but again I can’t be sure without a comparison. Another possibility is that the VVT values could be the target values rather than the actual values. I'm not sure what the readings are in MUT III. I understand that a patched ROM will allow both values to be displayed. Is there a preferred ROM to use?

If anyone has any advice or sees anything of note in the log that I should look at, please let me know. I want to get back on the road!


Thanks for the help,
Scott
 

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The issue started when I was checking lash adjuster clearances and I managed to drop one of the valve cover bolts onto the valve tappet on the exhaust side and I didn’t notice. I checked the clearances on half of the engine and when I turned the engine over to check the other half, I turned it pretty hard by hand without thinking. The stray bolt marred the side of one of the cam lobes and basically bent at 90 degree angle, but didn’t seem to do any real damage to anything else. Just glad they are aluminum. The scratch on the cam lobe was above any contact points, so it seemed like everything was ok. So, I put everything back together.
That sucks, nothing is easy is it.
Taking a step back... why were you checking your valve lashing if you are 100% stock?

There is a chance your MIVEC phaser is broken, and you would be able to see it not tracking correctly in the logs target vs actual. Step 1 should be updating to RAX logging. I have RAX logging enabled and at idle my VVT-Target = 0 and my VVT-Actual = ~0.3. Get RAX enabled, there is a sticky on one of these forums and the instructions are still accurate. Then upload your new log to Datazap. It makes reading and sharing these a lot easier.



Have you checked compression yet?
 

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Discussion Starter #4
I'll check the oil filter, I think I still have it. Hopefully nothing in there. I'm working on getting the ROM updated as well. Taking a little while because of limited time, but I'll get it. I was just checking the lash adjuster gap as part of the 60k checkup. No signs that there were any problems. I did a compression check as part of the checkup, but I can do another one now and make sure that looks good.

Thanks everyone,
Scott
 

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I had a little time to work on this during the week. First thing I want to do is backup the currently installed ROM on my ECU. I tried reading it with ECUFlash but it's complaining that there is no definition found. It seems like it should find it with all the definitions that came with ECUFlash. I would think it would fit one of the 2010 USDM SST definitions, but no luck. Is there a way to determine the id associated with the ROM? Despite the fact that it's called OpenECU, ECUFlash doesn't appear to have any open source code so I can't figure out what ROM binary looks like. I tried reading out everyone location of the binary as a 32 bit integer, both signed and unsigned, but nothing was in the right range. The definitions that came with ECUFlash have 55580005 and 55580006 for my year, market and transmission type but I also found a 55580009 rom somewhere without a definition. I'm wondering if that is the one I have. I'll keep at it and figure this out but I'm wondering if anyone has any suggestions?

Scott
 

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Discussion Starter #7
After failing to find a definition for my ROM, I made my own definition which seems to work properly. This is mainly so I can flash back to completely stock if I want to. I flashed the 2010 MR ROM with RAX logging enabled and logged the VVT values. I uploaded the log to datazap here: https://datazap.me/u/scog/log-1560737729?log=0&data=17-25-27-28-33

It looks to me like the exhaust VVT phaser is broken or not working properly. The log shows that it's stuck at -10 when the target is 0. I'm curious if anyone else has any thoughts or if there is anything else I should check on before pulling out the cam shaft.

Thanks
 

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Have you done any head/cam/spring work on your car? If yes, then double check your valve lashing, otherwise the replacement cam phaser will break too. Could try swapping the solenoid first, but the mivec gear is super sensitive to valve lashing when using stiffer springs. Mine has died once after poorly set valve lashing, and if it dies again I'm going with a mivec delete gear.
 

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Discussion Starter #9
I was actually checking the lash adjustment when this happened. Everything looked good at the time, but as I described above, I'd put an excessive amount of pressure on a stuck valve train, so I'm not sure what exactly happened.

I think I'm going to check time at the crank, as someone mentioned I might be off by a tooth, but I wouldn't think that would cause the VVT to be off. I wanted to get some logging before I made any changes so that I'll have a basis for comparison once I start making changes. On to the next steps I guess (i.e. check time, check VVT phaser)

Does anyone have good pictures of a broken VVT phaser vs a good one? I'm not sure how subtle the damage will be.
 

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I was actually checking the lash adjustment when this happened. Everything looked good at the time, but as I described above, I'd put an excessive amount of pressure on a stuck valve train, so I'm not sure what exactly happened.

I think I'm going to check time at the crank, as someone mentioned I might be off by a tooth, but I wouldn't think that would cause the VVT to be off. I wanted to get some logging before I made any changes so that I'll have a basis for comparison once I start making changes. On to the next steps I guess (i.e. check time, check VVT phaser)

Does anyone have good pictures of a broken VVT phaser vs a good one? I'm not sure how subtle the damage will be.
I'm sorry man, I asked that question and didn't even realize I responded to your thread already :)
There is a good writeup on it, but you have to google "MIVEC-housing-failure-how-common"
It's on one of the other forums.
 

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Thanks for the mention of datazap, will be useful as I begin my self tune route and solicit help from pros :)
 

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Discussion Starter #13
Looks like I found my problem. From what I'm seeing, it appears that the pin on the camshaft that inserts into the MIVEC/cam gear assembly sheared off. I'll add some photos below. Because the pin was still jammed between the assembly and the housing, they did stay linked together, which is why the cam didn't spin independently of the gear. I think when I broke the pin off, the gear and the shaft became unaligned by about a tooth. This would explain a bad idle that sounded like the timing was off even though the timing seemed to be correct. The cam gears and crank were all aligned, but the camshaft was not aligned to the gear.

At a minimum, I'm replacing the exhaust gear/assembly, the cam shaft and the cam shaft bearing. I'm thinking I'll probably replace the timing chain and tensioner as well. This must have put an extreme amount of force on it to make this kind of damage happen and I'm concerned that the chain may be compromised. I have the old revision of the chain anyway, so getting the new one is probably a good idea "while I'm in there".

Also, worth mentioning is that I did do a compression check before taking everything apart and it was good. So, I don't have any reason to think there was any interference (valve damage).

Any thoughts on this plan? Is there anything else I should check or replace while I have everything off?

As always, I appreciate any advice.
 

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To save a good amount of money, you can purchase the chrysler cam phasers. Same exact parts as Mitsubishi for A LOT less $$$.

Same with the cam bearing.


Cam phaser - Intake
Chrysler part # 5047021AA
Mitsubishi part #1147A010

Cam phaser - Exhaust
Chrysler part # 5047022AA
Mitsubishi part #1147A015

Cam phaser to camshaft bolts
Chrysler part #06509008AA
Mitsubishi #MN187128

Camshaft Bearing

Size 1 (black)
Chrysler #5047008AA
Mitsubishi #1016A030

Size 2 (colorless)
Chrysler #5047009AA
Mitsubishi #1016A031

Size 3 (Green)
Chrysler #5047010AA
Mitsubishi #1016A032
 

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Discussion Starter #15
Thanks. I knew there were some Chrysler parts in our cars that are much cheaper. I appreciate the list so I don't have to hunt them down.
 
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