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Hey Guys,

 

I have solved my cyl 1/3 missfire!! It was a bad knock sensor.

 

Car: 97 OBW, 5MT, 210K miles.

 

Some history:

 

Back during last summer I had an intermittent check engine light. When I read it with my handheld scanner it was defined as the dreaded 1/3 cyl missfire. After resetting it would stay off for a while, typically 6K miles or so. (I typically put about 20K on the car every year.)

 

During this past winter after resetting the code once again, it started to come back within 60 miles. Eventually it got to the point where the car would studder from 2200rpm to 2800rpm and clear up after that. After reading the postings about the knock sensor issue I replaced mine.

 

So far it has been 300 miles and all is well. I will keep you all posted of the results.

 

 

THANKS FOR ALL THE INFORMATION GUYS!!

 

Dean

 

BTW, This past weekend I installed new inner tie rods, new outer tie rod ends, and new ball joints on both sides. On the passenger front I installed new front wheel bearings. (I'm lucky as I have access to a hydraulic press :grin:) This car feels like new now!!!

Edited by doc526
rewording
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Congratulations. I finally gave up on trying to fix my 3/4 misfire after years of replacing every sensor, wire, switch, even the ECU, that could be suggested. My check engine light is basically always on, but never in the 240,000 mile life of the car have I ever felt any hesitation, missing, anything. It has always seemed to run perfectly. We don't have any emissions checks here so it doesn't matter.

 

I am about to get the car ready to sell. I think someone can get several more years of good service out of it.

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That kinda sucks. I hate not solving a problem but sometimes its better to throw in the towel vs loosing ones sanity. Good luck selling it!

 

Update....

 

After 600 miles it returned. :-\ To keep things simple and too ultimately figure out the problem, I am only doing one repair at a time. This time I changed the spark plugs. Found that plug from cyl #3's electrode was completely worn down to a nub. Cylinder 1 was partially worn and 2/4 were ok.

 

The old ones were the NGK PFR5B-11 and at $13 :eek: I was not going to do that. I went for the NGK BKR5EGP since they were $3 and I only had $20 in Autozone rewards.

 

So far it has been 150 miles and the car seems to be better than when I bought it.

 

 

Does anybody have experience with Yazaki wires? That is what the PO had on the car when I bought it.

 

Dean

Edited by doc526
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  • 1 year later...

I get a 1/3 misfire code every now and then but if it was not for scanning the code you would never know.. However Looking at my time I last did the plugs I was at 227,156 I'm at 247,256 now So that's what some 20K

 

I'm seriously thinking about putting the PFR5B-11 this time around

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  • 2 months later...

PFR is a platinum plug. The BKR is copper.

Honestly, I never thought the platinum plugs are worth the extra cost. Get a set of BKR5E11-ES (split point copper) and gap them at .039" they'll last for 30k miles easy, and will work just fine for the $10 investment.

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Im with Fairtax. The standard plugs seem to be ok. Im still running the same plugs and Yazaki wires from when I last posted. I pulled the plugs about a month ago and they still look ok, I might change them as it has been 2 years and about 40K since then.

Edited by doc526
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Im with Fairtax. The standard plugs seem to be ok. Im still running the same plugs and Yazaki wires from when I last posted. I pulled the plugs about a month ago and they still look ok, I might change them as it has been 2 years and about 40K since then.

well the other platinum plugs are only $15 so only 5 more.. if it was a sohc I would not bother with the platinum plugs. Funny thing is if I have a misdirected on 1-3 how is it still pretty smooth giving the firing order... Maybe its my exhaust leak right at the header output?
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well the other platinum plugs are only $15 so only 5 more.. if it was a sohc I would not bother with the platinum plugs. Funny thing is if I have a misdirected on 1-3 how is it still pretty smooth giving the firing order... Maybe its my exhaust leak right at the header output?

 

Mine never gave any symptoms of a misfire either. The code usually occured durning high speed cruising on the highway and the light would start flashing. 

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When I started this ordeal a while back,  the first question I wondered is how exactly does the computer determine a misfire. From what I have seen and read,  the computer looks at the crank sensor and if it determines that the crank speed is different than what it is looking for, it throws the code.

 

Some of the things I asked myself were what would cause a cylinder to slow down? My inital answer, poor ignition.  Next questions was what parts are associated with that? Etc and go from there.

 

I would start with the simple things first. Pull the plugs and check. Pull the crank sensor and check. I have heard about crud building up on the sensor causing them to drop the magnetic field that triggers them. Spray the coil with water. Check your timing.

 

Since it is happening at idle it seems that it what ever is causing it is pretty severe. 

 

Then if you do start changing parts, go one at a time. This way you can be certain that you have actually fixed what was wrong.

 

If I had not had an issue with a Hyundai I once owned, I would of called BS on the plug wire issue. I went through 4 sets of aftermarket wires before I returned them and bought OEM wires.  

 

Hope that helps.

 

Dean

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I really don't trust the misfire code right now for the fact that the car would not be that smooth at full throttle, If it was not for the CEL you would never know it's a misfire on 1 & 3..

 

This car ECU has an habit of making up codes sometimes when clearing the ECu by disconnecting the battery.. i was going to buy a spare from ebay but I haven't got around to that yet.

 

My vacuum at idle is -24 inch/HG

 

I cleaned the crank sensor last time I changed my crank pulley which was maybe 5 months ago.

 

Only thing I can say right now is my plugs are almost at 30K and my exhaust leak at the header output causes the idle to hunt.. before it used to be 3&4 and now it's 1&3..

 

I've had a real misfire before and that was because my old plug wires had a broken wire and was arching to the block and you would for sure know it was misfiring by the exhaust note and the hesitation.

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how old is the battery? I've had spurious codes set by a dead cell in the wife's Outback's batt.

No clue it's the same one I had when I got the car.. I always bring my jump pack when I look at the car and from the looks it was sitting for awhile so I had to jump it..

 

It's been fine so far in 16F weather..

 

Anyways here is a video I did not too long ago..

 

 

I have a question about checking the igniter not sure which terminals to check on the igniter side of things none of what I had here matched what I was seeing.. I was doing Pin 1 I think which is the closest to the firewall I was getting a number higher then what I think was shown here..

 

http://www.main.experiencetherave.com/subaru_manual_scans/FSM_Scans/coilpacktest.jpg

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Oh Cyl 4 looked like this.. Looks like the plug wire is in the wrong side/area so it's too short for 4 and ended up not making a good connection and ended up burning a bit of plastic on the inside.. shocked I never got 4 to show up in the misfire list...

 

I pulled the wire to Cyl 1 while it was running.. now that was a misfire..

 

IMAG0816_zps3b8ee924.jpg

IMAG0817_zps3e8d3121.jpg

 

A real misfire

 

Edited by 1-3-2-4
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Yazaki plugs wires would be the originals from 1997.  Might wanna replace those ;)

No, i brought them from subarupartsforyou.com and picked them up at the dealer last year during the summer.

 

Also last time I put the belt on the TB tensioner which is the old style.. I'd have to get a new or replacement one before I can do it again.. I went to pull my allen key pin and the metal that lines up with the plunger just broke off so it's impossible to keep the plunger down.. never thought I would see that.

 

When I do change the plugs this week might as well do a compression test on all 4.

Edited by 1-3-2-4
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LOL I found out what it was.. that was causing it.. the motor mount that bolts to the crossmember was loose, so that's where all that extra shaking was coming from, I ended up doing a compression test as well

 

My numbers..

 

1- 180 PSI

2- 170 PSI

3- 180 PSI

4- 145 PSI

 

I think 4 is because the shims got mixed up because they slid around in a box..

 

I did catch the ECU wigging out.. It threw me a ICA fail code but turning the car off and back on again and it works fine.. :-/

 

Going to need to helicoil the drivers side exhaust header stud for some reason that last one got really mangled, Still have a CEL for the 2nd O2 sensor but that's not a big deal.. Only thing is I hope the drive cycle for that is not long.. on each clearing of the CEL it resets it... the EGR one is the longest.

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  • 2 weeks later...

Pending code for 1 & 3 came back today

 

I have to narrow it down between the coil pack, injectors (252K miles) and knock sensor but not having a code for that..

 

my compression is 180 psi on both cylinders

 

possible fuel injection issue as well.. no codes today.. well be moving the injectors around to test.

Edited by 1-3-2-4
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