Mitsubishi Repair Problems? Ask a Mechanic for Answers ASAP
What model vehicle is this?
Please unplug the #1 fuel injector and see if the knocking stops or quiets substantially. Note the engine will run poorly of course, we are just interested in seeing if it changes the intensity of the knock.
No problem, we can pick up later.
The purpose of this test is to see if the noise is coming from the bottom end... when the fuel is cut there will no longer be any combustion, and if the noise is in the bottom end it will quiet down. We can repeat on the other 3 cylinders, but it sounds like you already have narrowed it down to the front of the engine.
If there is no change at all, we will next want to remove the front timing covers and check the timing belt tensioner condition as they have been known to knock real badly if they fail.
Thanks, ***** ***** rules that out most likely anyway. We will still want to check the adjustment of the mechanical tensioner too though; if it was installed incorrectly it will cause the same sort of noise as the tensioner extends.
Just to be clear, when you are saying cylinder #1, you do mean the one nearest the timing belt right?
Okay, just making sure we are on the same page.Lets do the injector unplugging tests and see if the noise quiets any, which again would indicate a problem primarily in the bottom end. If it does not change at all and you know your valves are adjusted properly, then we will still want to inspect that tensioner adjustment next.
With it sounding like the intake and water pump area, I have a feeling we will be dealing with a bottom end knock and it will likely get quieter when you unhook power to the affected cylinders' injector. Lets check it out first though and see if we are on the right track.
Yes, the easiest way would be to upload to youtube and then post a link here.
Yeah that isn't at all what I was expecting. That just sounds like valve train noise, a hair louder than usual but nothing really drastic.
When you adjusted the valves, did you do so hot or cold? What did you adjust them to?
Those are the right numbers... making sure of course you are using inches and not mm and the .008 is intake and the .012 is exhaust.
However you must do these with the engine completely hot or they won't be any good.
Lets run the engine up to full operating temperature and check your clearances again and see where you stand.
I'm attaching a chart to help with identifying which valves can be adjusted when; the white arrows are for when the engine is at TDC (mark on cam at 12 oclock) the black arrows are for BDC (mark at 6 oclock).
Well that would certainly be really useful information!
Yes, lets take a look down into the cylinder that had the plug failure. If we lost any part of that plug down there we've got issues.
Check for debris first and foremost, but also look for signs of damage from foreign matter being in there previously as well.... any marks at all on the cylinder walls primarily, but the face of the piston and if you have a reverse head camera end the combustion chamber as well.
Hmm.Unfortunately at this point I think you are probably going to need to pull that head for inspection.I don't really see any other real expectations... the sound sounds like the valves are out of adjustment, but you are certain they are fine. That does leave debris in the cylinder as a suspect as it sounds the same, but nothing is found there even though we know we had a plug fail.
A little yes.... do you have excessive play? Like it moves all the way to the advanced position for mivec?
Not really.... you either have engine vacuum or you do not. You should have 15-17inHg at idle (varied 15% or so depending on altitude), if you do not then there is a problem with your valves (be it mechanical problem, timing problem, etc).If #3 is soaked in fuel, are you certain you have spark there and are certain you have good compression there?
Are you certain you have spark there, regardless of the newness of the plug?