Stubborn misfiring continues 91 Legacy (cylindar 3)

[DavieGravy]

Here's what I've done but the problem persists

 

New NGK spark plugs properly gapped

New spark plug wires

New coil pack

New ignitor

Checked for vacuum leaks

Cleaned MAF sensor

Cleared and pulled ECU codes (only one I'm getting is for the colant temp sensor)

 

I don't see how the colant temp sensor can cause a misfire, so I figured I'd try and replace the fuel injector. The cylindar is #3 (back passenger)

 

My question is, how do I replace the fuel injector? I removed the two screws, the electrical connector and the cap, but it won't come out. Do I need a puller of some sort? Can someone PLEASE give me quick, detailed instructions?

 

Thanks in advance.

[bheinen74]

first off, if you are even thinking about replacing the injector, you need to depressurize the fuel system in the rails first and foremost. In the trunk there is a access panel cover on the pasenger side with 4 screws to get to the fuel pump connector. remove cover, Unplug connector. then start car and let run until the car dies. When it dies, the fuel system has lost its pressure.

 

if you do not depressureize, all the fuel will leak into your cyclinder.

Oh, and to remove the injector, you need to twist on it and pull slightly. one of these works well

Edited May 24, 2010 by bheinen74

[johnceggleston]

Cleared and pulled ECU codes (only one I'm getting is for the colant temp sensor)

 

I don't see how the colant temp sensor can cause a misfire, so I figured I'd try and replace the fuel injector. The cylindar is #3 (back passenger)

 

others will know more, but i would address the coolant temp sensor code first, then move on to whatever else. the code is there for a reason. the temp sensor can cause the engine to run too rich.

 

did you use subaru wires??

[WoodsWagon]

Temp sensor is a good place to start, but it won't fix the missfire. I hate to say it, but cyl 3 seems the most susceptable to burnt valves. I would do a compression test to see what you have, and a leakdown test to see where it's going.

 

The injector on 3 is the last in the line of the fuel rail, and it seems to get clogged most often. That makes the cylinder run lean and burn up exhaust valves.

[heartless]

definitely depressurize the fuel system!! my car wont actually start after pulling the fuel pump connector, but cranking it over for a few seconds is usually sufficient to depressurize the system.

 

I found it easier to pull the entire rail when i changed my injectors (i did all 4 due to misfires on more than one cylinder) - gave me a little more room to work.

 

the injectors did not come out easily on mine - i had to both pull and pry gently around the edge. (a second pair of hands is always useful here). seems to me I gave each a little shot of PB Blaster to help loosen/lube up the O-rings - would not recommend doing this if the rail is still on the engine...

 

seating the new injector properly is made a little easier by giving the O-rings a VERY light film of engine oil - helps them slide into the rail without binding up

 

Good luck

[DavieGravy]

Thanks for the helpful advice. I'll try it and post back.

[DavieGravy]

Thanks everyone for the succinct advice. Replacing the fuel injector fixed the misfiring problem. I had a hell of a time trying to get the injector out of the fuel rail so I ended up replacing both passenger injectors and the rail itself (20 bucks from the junk yard). Strangely enough, the old fuel injectors had only one hole to squirt the fuel through whereas the new ones had three holes. Perhaps this was something subaru changed due to clogging problems.