98 EJ25D Forester Misfire #1

[torxxx]

Friend brought me his forester that he had just bought a few weeks ago. Its been having major #1 misfire problems. Before he brought it to me, he changed plugs/wires/injectors full tuneup etc on the engine and it still has the misfire. Considering its a DOHC valve smasher I decided to pull off the T-belt covers and inspect the timing marks to see if everything was in sync and it was. The only thing I noticed was it had a brand new belt on it.. Meaning 1 of 2 things.. Someone did preventative maintenance on it (which there is a severe lack of up here in Alaska) or the belt broke and they replaced it. I'm leaning towards belt broke at an idle due to the compression readings I had

 

#1 125 psi

#2 184 psi

#3 179 psi

#4 180 psi

 

The numbers arent within 10% so I'm thinking it has a valve seat issue or a slightly bent valve that wont seat shut all the way. I've seen it happen a few times on these DOHC engines when the belt broke and it actually didnt bent the hell out of the valves.

 

so talking with him, I mentioned what it could be and he said just fix it. He doesnt care what it costs to pull the head off and replace all the valves on #1 and do the head gaskets on 2/4 since I'll have the engine out anyways.

He is planning on selling the car and wants it in top shape for the friend he is selling it to. The good news on this job is I'm getting a 1992 SVX out of the deal for doing the work. The SVX is in great shape 175k miles on it but it runs like a champ, and doesnt have any signs of trans issues from what I could tell. Either way its a EG33 and I've always wanted one to play with.

 

so yeah anyone else thing of ANYTHING else that would be causing this misfire on #1? Its massive at idle and as u drive it seems to smooth out. I plan on doing the HG's and valves just to humor him but I want to make sure thats going to take care of the issue. What do you guys think?

[lmdew]

If you can do a leak down check that would confirm your thoughts and current tests.

[wtdash]

FWIW, I just asked about a '99 Forester for sale - I know it's a different engine, but maybe this info from the Seller will help:

 

... hooked up a computer to the engine and it said "4th cylinder misfire". We started troubleshooting by first replacing the plugs, then the wires. The man at the Subaru dealership recommended changing the ignition coil, which we did. With the problem still unresolved we pulled the engine out and pulled the heads off and replaced the valves, valve guides and timing belt. When we put the engine back together, the problem still existed. A compression test was done and the 4th cylinder is getting 40 psi. Everyone I have talked to has said it's the piston rings that I need to fix. Despite the problematic 4th cylinder, I have been fine driving it and been getting between 21-24 to the gallon.