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Thanks. After further talking with the mechanic, it comes out that he does not have the tool, and was balking at adjusting the valves, because labor for him without the tool would be similar to pulling the heads. We also dicussed that the valve could possibly be damaged and or burnt. The fact that the misfire has become so prevalent in such a quick period of time could mean this. The course of action is he will check clearance, and we will go from there.

My car has a progressively worse miss on cylinder 4. I've done the typical stuff, plugs, wires, coil, cam position sensor, crank position sensor, fuel filter, clean EGR, etc. No improvement- problem is getting worse with milage. Miss mainly occurs at idle, seems to clear up at higher rpm. I took the car to a "subaru specialist" private mechanic, because I suspected the valves were out of adjustment. Mechanic tells me compression in cylinder 4 is off by 15 lbs (similar results to my test), and that it is a valve issue. However, he is saying the do not normally need adjustment and he needs to pull the head and replace the valve. My understanding is that they are adjustable, and subaru has a 100,000 mile service interval to check these? After questioning this, mechanic tells me even if they are adjustable, he needs to tear down the head to reach them and at that point he might as well take the head off to replace the valve. What is your opinion here?

I'll check again for leaks. The EGR valve looked like it had a good seal, and wasn' that dirty. Thanks for the suggestions.

I've already changed the plugs and coil. Its not the coil. I would expect that if there was a valve adjustment issue I would also have a compression issue, correct?

Ok, so for the past month, I have been getting a recurring P0304- Cylinder 4 misfire detected. It typical happens at idle or low load. It seems to accelerate fine. At first it was occasional, but has been getting more and more prevalent. I'm at wits end trying to take care of this. I've replaced spark plugs, wires, coilpack, and fuel filter. I've swapped fuel injectors with a different cylinder- no change. Compression test shows 150 PSI on the cylinder- same as the others (I live at 7,000 feet- the cylinder pressure is typical). I've cleaned out the EGR valve and checked that the valve wasn't stuck. I haven't checked the EGR solenoid because I'm not sure how. I need other suggestions. Thanks!

Actually, I bought another Subaru shortly after this happened as I needed to drive cross country. The only reason I was looking at fixing this was to sell it (and get it off my property). And I am not putting the money and effort into replacing the head, and possibly the whole motor if the pistons are badly scarred. Unless somebody can come up with an explanation that doesn't involve the valve smacking the head hard enough to break a cam, I'm not tearing this motor down any more.

This will be long, but hopefully interesting. I need some engine sleuths to help me explain this one. I'll start with what happened- 1990 Subaru Legacy Wagon AWD Auto with 138k on the clock. I was driving home from a 200 mile round trip. About 50 miles away from home, in an area absolutely deserted, the car suddenly lost power and started sputtering, missing, and smoking, with a lot of lost power. I decided to keep driving it to see if I could make it home, for one, I had bought the car for $750 and a 50 mile tow would cost about half that, so I decided to risk it. I made it about 25 more miles before the car then lost even more power, to the point where it would not stay running in gear. At this point I took my losses, and had it towed home. At first, I was sure that the timing belt had skipped. So, it was to my complete amazement to find that it had not- all the pulley marks lined up perfectly. At a loss for how it was running, I tried a compression check. Surprise! Zero compression on the 2 driver's side cylinders. At that point I was stumped. The only thing I could come up with was a massive head gasket blowout between the cylinders, but if that was the case, I would have had milkshake oil or oil in the coolant, which I had neither. I bought another Subaru and let this one sit for most of a year. Finally, I decided I needed it out of my garage and tore into it to see what was wrong, with the thought of fixing it and selling it. Things I found: ------------------- 1. The camshaft was snapped in two pieces just behind the oil seal housing. 2. All bearing surfaces on the camshaft look fine. It did not seize in a journal, and both pieces freely spun. 3. The camshaft keyway for the cam pulley looked perfectly fine (not chewed up) but there was no key to be found. 4. Rocker arms look fine, and I don't see broken valve springs. Aside from the broken cam, things look normal under the valve cover. ----------------------------- I've NEVER heard of a Subaru breaking a camshaft. As far as I can figure, the only 2 ways enough force could be generated to do this would be if a journal seized, or if a valve got jammed against the piston. As I can't see that a journal seized, it must be valve interference. Right? My temporary hypothesis is that the cam gear could have shifted position on the cam as there was not a key to hold it in place for some reason. This, the car starts to miss and lose power. Eventually it shifts so far that a valve contacts the head, and the camshaft snaps. Problem with this hypothesis- 1. Why did the cam snap instead of the timing belt shredding or skipping? The belt did not jump- it kept the exact same relationship with the cam gears. 2. If the cam gear shifted position on the cam, sending that bank out of time, wouldn't it continue to spin? If it had already started to spin, I don't see how it wouldn't give before there was enough force to snap the camshaft. ----------------------------------------- The main point of this exercise is to see whether there is a point to continue working on this engine or to just junk the car. I'm not willing to replace the head, and I can't imagine the valves would still be working if they smacked the piston hard enough to break a camshaft. What do you think? :popcorn:

Thanks. Ironically I tried it today, and the a/t light didn't flash at startup, so I drove it to run errands. No light the whole day. My guess is that while fumbling around to find the diagnostic leads, I inadvertently reseated a loose connection or the like. Still, its good to know how to do this, and also that if I get a code 16 again, it isn't mission critical and I can keep driving the car in the short term.

Anyone? Not sure where to start looking to resolve this...

Progress! I'm getting code 16. Based on this- http://www.ultimatesubaru.org/forum/attachment.php?attachmentid=1333&d=1091550284 It is code 16 : Torque control cut signal Detects open or shorted input signal circuit. What is that?

I want to make sure I am correct here. I see the black terminal, and I also see in the same area 2 green single wire connectors that in my 1990, put it in diagnostic mode when connected. Are these 2 wires with the green connectors the ground wires, or are there 2 more up there than I need to get free?

Either one of the green terminals is a ground???

Do I just ground terminal 5 to anything, or is there some lead on the harness that I am supposed to plug in?

Also, I suspect that it is one of the sensors because the code will set every single time, even if I did nothing the previous run cycle but idle it in park for a few seconds. I think with duty C and the other tranmission operation solenoids that you have to drive it to 20 mph for a code to set?

No torque bind. I did tight turns both in AWD and FWD modes and don't have any problems. I think I realize what I did wrong. When it talked about entering diagnostic mode, I thought it meant plugging the Green connector together under the dash. I take it grounding pin 5 is a paper clip trick? Anybody have a picture/diagram or good descrption of which on pin 5 actually is, and which is the ground pin?