Replaced timing belt after it jumped a tooth. Cylinders 1&3 were 90 and 80 psi respectively, now 210 and 60 respectively.

[kevinrse]

Legacy EJ25D 2.5L DOHC.

 

Engine began running rough and idling rough a few weeks back, CEL diagnostic codes said cylinder 1 & 3 misfire. Diagnosed with a compression test. Cylinders 1 and 3 were getting 90 and 80 psi respectively. Cylinders 2 and 4 were 190 and 180 respectively.

 

I just put the timing belt back on and re-checked compression on the right side. Cylinder 1 is now getting 210 psi, but Cylinder 3 is only getting 60. (Note---I did this before the engine was all back together, so I didn't idle it beforehand and the compression test was run on a cold engine.)

 

I'm pretty sure I got back the power I was lacking when the timing belt slipped. Just took it for a spin and it feels about the same as I recall it in terms of acceleration. So, it's possible that cylinder has been underperforming for some time...

 

Now that I have the results of a compression test and verified timing is like new again, is there anything further I can do without getting into expensive territory (valve work... piston rings etc.)? This is an old car (228k miles).

[1 Lucky Texan]

doubtful - if you were extremely lucky, some marvel mystery oil might free-up a sticking valve. more likely it is; sticking, dropped guide, bent or burned. much less likely would be a cracked piston ring i guess?

 

there are borescopes made for looking around in there thru the plug hole, but i dunno if one can be rented or not ????

 

if you get a used ej25 , you'll probably need to put MLS head gaskets on it.

Edited May 21, 2014 by 1 Lucky Texan

[kevinrse]

Thank you. What will happen if I keep driving with any of these problems? I.e., can I drive on 3 cylinders for the life of the car with no other consequences, or will it eventually cause bigger problems? I have a friend with a borescope so I will try to borrow it sometime soon.

[1 Lucky Texan]

depends on what's wrong but, generally, just variably bad stuff - nothing good.

 

 

 

could be; more stress on the cat converter, engine might get more load=runs hotter, if a ring is cracked, oil gets diluted with fuel, valve seat may erode.....

 

 

dropping the exhaust might allow inspecting for a dropped valve guide.

 

Edited May 21, 2014 by 1 Lucky Texan

[kevinrse]

Per a friend's advice I just performed a leakdown test. I give this info in a new thread. If you are interested check it out here.

 

Thanks again for the help y'all!