- This topic has 4 replies, 4 voices, and was last updated 9 years, 4 months ago by
.
-
Topic
-
Hello, I am new to the forum but have been watching Eric The Car Guy videos for a while. I was drawn to the website because of a problem that I have not been able to fix after going through several videos and doing other research. The car is a 1997 Subaru Impreza with a 2.2l motor with a Mass Air Flow style sensor and manual transmission/AWD. I drove my car one day and it was running like a champ, like it has since I bought it. I didn’t have any problems with the actual motor but the next day I replaced my brake master cylinder. I get it replaced without serious drama, get everything bled and I go to start it up to see how the pedal feels and all of a sudden it runs like crap. The pedal feels pretty good, but it runs like crap. It shakes at idle cold or warmed up. When you rev it up, it smooths out but there is obviously still a miss-fire. It also smells bad, like it’s running rich I think, but not backfiring or anything.
There is a check engine light and I get the code P0341 for the cam position sensor. So because I was messing around in the engine bay, I figure it’s a vacuum leak from a hose that had come off or maybe a plug that was undone for the sensor. I haven’t been able to find any vacuum leaks (tried carb cleaner, smoke, pressurizing the system) or electrical plugs undone, loose wires, nothing. I’m also pretty sure the booster is good and I imagine you could have a vacuum leak from there. I check the coil for continuity, the plugs and wires are pretty new and all the fuel injectors are clicking.
I also tried the method of trying to find which cylinder is the problem. The only thing that seemed to stand out is when I take the number 1 cylinder spark plug wire off the plug, the engine rpm doesn’t change AS MUCH as when I remove the other three. It only changes sound a little bit. I’m getting spark all the way to the plug. I take out the plug and it looks pretty decent (it’s not old at all). There’s a little soot on it and it’s slightly out of gap so I clean it, gap it and put it back to no avail. I replace the cam position sensor to no avail. I did some research that says you can get the same code if there’s a problem with the Crank position sensor and that’s what the guy at the auto part store told me, which makes no sense to me since there’s a separate code for that. I replace the crank position sensor to no avail. I bought the manual for the car and have been trying to trouble shoot but I’m pretty much out of ideas. I keep asking myself what I could have done while in there replacing the master cylinder? Sorry for the lengthy post, it sort of turned into a venting frustration rant, haha. Any ideas would be helpful, thank you.
-
Replies
-
Here are some things to check. Try cleaning the connector with brake clean.
If you have access to a scan tool that can pull up PIDS then look at your long term fuel trim and see what’s going on. Also, any generic scan tool can pull up Mode 6 data where you can find misfire counts for each cylinder. Hope this helps.
Did the check engine light come on once the misfire started or has the light been on for some time preceding the misfire? I never have access to a good schematic for any Subaru I’ve met so I can’t say much for the code. I did find enough to say the crank and the cam sensors are both PM generators. Since you replaced both sensors, you might be chasing a wiring or PCM problem. You might want to look into special procedures for setting an air gap for either. If either sensor has a bad gap, they can’t do their job.
Did you try moving the spark plug to another cylinder? If the misfire moves with the plug, one of your new plugs is a dud. You could try swapping the fuel injectors around in the same way. You could have one partially stuck open and that might explain the soot and the rich smell.
Have you tried a compression test yet? Subarus are notorious for head gasket failures and the improved running condition off idle can support the possibility. A leak down test would be a better step yet to isolate the source of a mechanical fault.
- You must be logged in to reply to this topic.