Well the verdict is in. There is a misfunction of the intake valve/valves on cylinder 6. I did a leakdown test and got less than 3% but the tech told me it may not be a sealing problem...if may be a opening problem...IE, the cylinder is not getting enough air to combust properly. He also said whatever the problem is with the valves it's VERY small in terms of impact to the engine. Which I kinda figured since it runs great after you get past 1200-1500 rpm. I asked him how sure he was of his diagnosis. They said 100%.

I have to admit I was impressed with the diagnosis procedure and the cost. They worked on my car for3 hrs just going over everything I had already gone over and only charged me $105!! If I'm allowed to say it the dealership was York Mitsubishi and I'll be headed back if I'm stuck. Mods, please delete their name if I'm not. So, might as well shoot the friggin' moon on this thing. I'm going to do timing belt and all that jazz, water pump, rebuild both heads etc, etc. This really sucks timing-wise since I can't use my lift. I have a M3 turbo project on it right now and can't take it off the lift.

One other thing I noticed and it goes with something winshawn mentioned. My montero had a "tick" from day one on the left bank andidled a bit rough too. Knowing NOTHING of the engine design , I've read that the Mitz engine uses hydraulic lash adjusters. It uses them on the OPPOSITE end of the rocker arm from the valve stem. Therefore, if one collapses you will not achieve the "lift" you should. I'm just wondering ifI have a collapsed lash adjuster and I'm not getting the air to cylinder 6 that it should see and it that is the problem. I say this because my very light "ticking" noise is gone. Anyone shed some insight on this? Am I correct or incorrect in my theory?

I'll be removing the heads this Friday, recondition them on Saturday morning, start reinstalling everything Sat afternoon. Of course, this is baring any other damage. I gotta get busy buying parts now.......oh boy. As always I'll post my final results...hopefully it will be good news.

Don

 

Just a thought as you mentioned it may be a lash adjuster.. If this is the case why pull the heads just replace the two lash adjusters on number 6 inlet and exhaust and see how she runs. Might save you a lot of work and quite a bit of cash in the long run...

Regards

 

I considered this very thing...but since I have to remove the intake plenum each and every time you do ANYTHING to this engine I figured I pull both heads and clean them while I'm at it. That way I can also check for valve sealing problems and/or bad valves. Also, my 60k timing belt replacement is due anyway(66k miles). I just bought the following for $245 including tax and shipping:
1. Complete head gasket set, both sides, includes valve cover gaskets and seals, valve seals, front cam seals, right rear cam seal(there isn't a left cam seal, wierd).
2. All intake plenum gaskets including the throttle body
3. Timing belt, idler pulley adjuster pulley
4. Oil pump seal
5. water pump and gasket kit.

It all should be here on Friday. I want to get it apart by Friday night because if it is a collapsed/damaged lash adjuster and can get to the dealer sat morning and get one.

I'm looking forward toit actually...wierd as that may sound. I've never opened up a Mitz engine yet. I have experience with the domestic brands, MB's and BMW's but never any asian stuff.

 

Your keen what can i say. Yes its a bit of work ripping the manifold off. But the rest not for me. I cant believe how much you need to remove just to get the timming cover off. Hope it works out for you. Be careful with the timming belt dont want to get this part wrong. If you have time can you take some pics of the tear down. Would like to see the guts of this engine especially the timming belt assembly. Seen it in workshop manual but real pics would be great.

Good luck with it..

Regards

 

Cool - glad you are tracking down the culprit. Make sure you absolutely line up marks and put engine at TDC with timing belt. Ive done a number of timing jobs and this engine was the first where a cam slipped. I had to use a strap wrench on the pulley to get everything lined up again. Keep us up to speed on your progress. I would add the following to your parts list for the 60k service - plugs, wires, crankshaft bolt. Since you have the intake off, its minutes to replace the rest of it - oh wait, you replaced these already....

 

To me, taking the heads off is about 3 times the work of taking the intake plenum off, but that is your choice. I would be curious to see how much of a ridge you have on the cylinder.

There is something called a purge valve on these engines that tick time to time. It sounds like a lifter tick, but it is completely normal. Could that have been the tick you heard? My lifters are totally quiet all of the time.

If it is a valve timing problem it must be a lash adjuster problem. No?

 

No doubt it's more work. But don't forget, although the Tech is quite sure the valve(s) are the "problem" neither he nor I know exactly what IS the problem. Even if I find a collapsed lash adjuster on #6 I don't know if there is valve damage....or perhaps a tight stem. Also, based on the fact that I looked down the intake and saw more carbon/junk on the back of the intake valves then I'd like to see. I'm going to play it by ear and go at as I come to it, so to speak. But I'm fully prepared to pull both heads if I don't like what I see.

I'm pretty sure that I can WITHOUT removing the cams?Anyone know? This is the 6G74 SOHC 3.5. If that is the case, my worse issue will be removing the exhaust manifold collector bolts. I mean once the intake plenum is off the heads are sitting there. I have to drain the coolant anyway for the new water pump install.

This "purge" valve you are talking about is it the EVAP purge valve?

Thanks,
Don

 

Yup.

 

...I've held off on this a bit to complete another project. I'm hoping to get to it this weekend.

I promise I'll post pictures in case anyone else has this trouble. My wife is still driving the Monty since her commute is so short(3 miles each day).

I did flush the motor with AutoRX just to prepare and thought maybe I'd get lucky if a piece of dirt was in the lash adjuster...but I've never had any luck with "instant fix" products anyway

 

Just to let you know, she goes under the "knife" Sunday Morning at 7am. I will post results/findings.

Don