Best engine decarbonization available

[desertdude]

Well at least now you have a super clean engine  First with water and then with terraclean. Most probably a burnt valve 

[Rahimdad]

More research required and hopefully someone who is technically more knowledgeable can point us in the right direction.

[Rahimdad]

@Gaurav Sirjee, I was going through another forum and read a post that might help you with your vibration issue.

I Quote:

Hi all im new here hope someone can assist. I have a 2001 NM Pajero 3.5 Petrol Engine. Since buying this vehicle a few months back the engine has a shake on idle. Recently i have converted the vehicle to LPG so it runs both fuels via a switch. I still get this shake using LPG fuel. I have played with the idle screw upping the revs but ECU relearns its idle so it goes back to normal after a couple of days. I have been trying to resolve this problem for a while now but no luck as yet. Plugs and leads were replaced just over a month ago with genuine mitsu items. This is what i did today. I lifted the rear of the trany still get the vibration/shake. Lifted the front of the engine still get the vibes. Checked balancer no wobble observed. Other parts i have swaped which i had access too as follows. Complete set of Ignition coils. EFI Temp Sensor. Throttle Position Sensor. Ingiter the item that sits next to the coils. O2 sensor was done the other day. Basically all the sensors except the Airflow Meter cause we couldn't find it where it was stored. Removed throttle body and gave it a good clean with throttle body cleaner even though it was already cleaned. Cleaned PVC valve. ISC checked and working. Re checked all hoses for leaks. Checked manifolds for leaks as well. Still get the vibes on idle. Next step is to remove the timing cover and check the cam timing. I have a feeling the person who replaced it may have botched the install. Can't believe i spent the whole day on it and no closer to sorting the problem out. Any further tips or advice most welcome

I know that you have replaced all sensors and checked out most of the stuff mentioned above if not all. So his next post is more interesting and might hold a solution to your problem. Here goes.....

OK now for the conclusion. I have some good news. Its fixed.  
Took it to my mechanic today we pulled the timing covers off and all the other bits and pieces in front of the engine. Our findings are as follows. Passenger side camshaft was out by one tooth. Tensioner on timing belt loose as a goose the belt had a fair bit of play side to side. Basically since we had it pulled down suggested we replace the timing belt anyway. Timing belt had been replaced by previous owner obviously it wasn't done correctly. I consider myself very lucky the belt didn't jump any further otherwise i would have suffered the good old bent valve syndrome and other damage associated with this. Anyway we put the thing back together and it just purrs like a kitten now. So quiet so smooth even with all the accessories on placing a load on the engine. Such a sigh of relief finally. I have been chasing this problem for a while now and can happily say its sorted. Best part was the cost. All up $300.00 which included the belt and labour associated with this piece of work. Thanks all for your suggestions. Best Regards.

So maybe when we go to collect the car today we can do a little check as suggested above. What say?

[Barry]

The timing is 100% spot on. I know because I did it myself and I have 100% faith in my work. After cleaning the lifters, refitting the cams and fitting new timing belt, tensioner and pulleys, I spun the engine twice, checked the timing, spun it twice and checked it again and everything was good. When another professional investigates properly, they will come up with the same diagnosis as I did, main misfire caused by a leaking exhaust valve on the centre cylinder on the drivers side. Some of the other valves aren't good but this one is the main problem which I advised on before carrying out any work. No amount of magic potions or quick fixes will cure this. The only solution is to remove the head and repair the valves. 

[Rahimdad]

@Barry Good to know, thanks for sharing.

[Rahimdad]

Just one question Barry, what happens if you drive as is and how long before something worse happens?

[Gaurav]

This is exactly what I am doing since over a year now and nothing catastrophic has happened, simultaneously I am always on the look for some new experiment and ideas in a hope to fix it. That's the other thing that this "hope" has already costed me 3 times the cost of scrap engine, but again I reached to mental satisfaction state now that almost all inside engine component (except valve) is healthy, clean and almost 90% functional for a 17 year old beauty, that still keeps pace with Jeeps and Patrol in desert.

Next fun project will be the borescope camera that I ordered to actually see the main culprit hiding inside, before I make the big decision to swap the engine / rebuild.

[Barry]

@Rahimdad it could run for a long time and not have many issues or it could run for a short time and have many issues. I wouldn't like to speculate. 

Some of the potential issues of a leaking valve could be,

Intial low power. You're only running on 5 and a bit cylinders rather than 6. 

CO, NOx, HC etc readings will be off. Bad exhaust gas readings picked up by the lambda sensor can cause fuelling issues, leading to more bad running.

Bit of the valve could break off and fall into the cylinder, damaging piston crown and or cylinder wall. 

Bore wash. Because the fuel is not being burnt properly, it can remove the lubrication and cause scoring. 

Again, because the fuel isn't being burnt properly, some of it can end up in the sump mixed with the engine oil. If the oil isn't changed regularly, this thinner oil/fuel mix doesn't lubricate properly and can damage all sorts of things. 

Again unburnt fuel. It can enter the catalytic converter and decrease efficiency. 

There is a chance of head/block distortion if the cylinders are running at different temperatures. 

[Gaurav]

Thanks Barry for quick insight just like car dealership: You can drive until engine run extremely rough or dies completely, whichever comes earlier. lol.

Btw, slight correction buddy it's not 5 cylinder now it's 5.5 cylinders so I ought change the sticker to V5.5 too.

Jokes apart, once I get the borescope will swing by to do another compression test, oil change and have a look inside.

[Rahimdad]

Hmmm... and the search for a banana or potato solution continues.