Check Engine Light Blinking after timing chain Tensioner Replacemen Fixed - Now P0420

[dbullen]

any chance something like a bad cam sensor on that side could cause this?

 

is it cam = fuel and crank = spark, i can't remember?

 

All fixed, took it to the dealership, passengers side chain was two teeth off, no damage done luckily, just another 9 hours of labour @ 80/hr

[tcspeer]

Very good Shawn! How did you know it was pass. side?

 

I see after rereading post the misfires was on that side, but I also had no ideal it had two chains, in fact I didn't know any Subaru had timing chains.

Sounds like he didnt get the pass side bank chain lined up perfectly to me. Possibly bent valves but not terribly likely with all 3 misfiring on the same side that almost has to mean he didnt line up the chain instead of damaging something. If he had damaged something the problem would usually be far worse sounding at idle.

 

The engine looks like a chain driven EA82 engine with 2 extra cams and 2 extra cyl's every time I look at it.

 

Unfortunately it is an interference engine so valve damage is always potential BUT it still sounds like 1 tooth off.

 

Its also very possible he pinned the tensioner too fast in a vise. You need to watch it as it compresses squarely as you can bend the piston in the tensioner if you do it too quickly.

 

Agree with above...dont let GM tech work on Subie.

[EVOthis]

i thought all the H6's were chain driven.....i could be wrong..... is the svx engine belt driven? that is great that you got it fixed though......i dont think thats really to bad of a price I work at Sunoco and we charge $75/hr......

[nipper]

SVX has a belt. The H6 has two timing chains in order for it to fit in the space of a H4.

 

nipper

[EVOthis]

thanks nipper....ive had the question for a while....guess i forgot to ask it....

[mdjdc]

I'm gald that you got up and running. Now I'll admonish you one more time!! No more GM mechanics. If they don't know subies than go elsewhere. My friend is a master mech for subaru and he told me that three teeth off is enough to cause valve damage, so you were very lucky. Count yourself Blessed and don't do that again.

 

Let's just say, lesson learned.

[dbullen]

Car seems to have been running fine since fixed until today. Check engine came on light again. Read the code, P0420 Catalyst System Efficiency Below Threshold (Bank 1). Does this sound like the Cat is bad? possible due to the timing being off? Or could this be that the timing is still off somehow and still causing a problem? or maybe something else all together.

[nipper]

How many miles on it?

 

 

Usually it means the O2 sensor is tired and needs to be replaced (the front one).

 

nipper

[dbullen]

129,000 miles, don't have service history so not sure if O2 Sensor was replaced before. The cost of O2 Sensor sounds much more reasonable! Am I doing any damage if I leave it? Just reset code and was going to see if it comes back. Anything I can test to see if the O2 Sensor is the problem?

[nipper]

129,000 miles, don't have service history so not sure if O2 Sensor was replaced before. The cost of O2 Sensor sounds much more reasonable! Am I doing any damage if I leave it? Just reset code and was going to see if it comes back. Anything I can test to see if the O2 Sensor is the problem?

 

Yup your due for an O2 sensor, You possibly arent doing damage aside form your gas mileage. Also if you live in an emissions stae you wont pass emissions.

 

you have the code read, so we know what it is. O2 sensors wear out with time, and the mileage matches it. There are other things that can cause it, but your car is a bit young to have a leakey exhaust system.

 

Yes you can test it with a meter to see whats going on, i'm sure someone will say how, but personally, i would just clear the codes, and wait till it comes on fully, then replace it.

 

(thats what i usually do)

 

nipper

[dbullen]

Yup your due for an O2 sensor, You possibly arent doing damage aside form your gas mileage. Also if you live in an emissions stae you wont pass emissions.

 

you have the code read, so we know what it is. O2 sensors wear out with time, and the mileage matches it. There are other things that can cause it, but your car is a bit young to have a leakey exhaust system.

 

Yes you can test it with a meter to see whats going on, i'm sure someone will say how, but personally, i would just clear the codes, and wait till it comes on fully, then replace it.

 

(thats what i usually do)

 

nipper

 

Would I have two Front O2 Sensors?

[OB99W]

Would I have two Front O2 Sensors?

Yes, one for each bank.

[nipper]

Would I have two Front O2 Sensors?

 

That I am not sure of. I am not that familiar with the 6. I cant tell by 1st suabru's parts either, nor is your exhaust system on the walker web site either.

 

 

(Just so this can be searched Oxygen Sensor )

 

 

nipper

 

PS someone answered it

[dbullen]

That I am not sure of. I am not that familiar with the 6. I cant tell by 1st suabru's parts either, nor is your exhaust system on the walker web site either.

 

 

(Just so this can be searched Oxygen Sensor )

 

 

nipper

 

PS someone answered it

 

Here is a diagram of exaust, I guess it looks like there is two front O2 Sensors, and I'm guessing bank 1 is the passengers side? Same side that the timing was off (Cylinder 1,3,5) . My mechanic who did the work originally and messed it up I do remember him saying if the timing was off it could somehow possibly ruin the cats?

 

[nipper]

Here is a diagram of exaust, I guess it looks like there is two front O2 Sensors, and I'm guessing bank 1 is the passengers side? Same side that the timing was off (Cylinder 1,3,5) . My mechanic who did the work originally and messed it up I do remember him saying if the timing was off it could somehow possibly ruin the cats?

 

 

On a modern engine, it really takes a hell of a lot to ruin a cat. Engins run so lean, its hard to run them so rich as to ruin it. The O2 sensor is before the cat, and takes more of a beating. Since you are at the age to replace O2 sensors, replace the one. Worst thing that would happen is that you still need to replace the cat (and replace the O2 sensor because of age). Best (and most likely thing) that will happen is that we saved you 700.00

 

 

Either way a win win.

 

nipper

[dbullen]

On a modern engine, it really takes a hell of a lot to ruin a cat. Engins run so lean, its hard to run them so rich as to ruin it. The O2 sensor is before the cat, and takes more of a beating. Since you are at the age to replace O2 sensors, replace the one. Worst thing that would happen is that you still need to replace the cat (and replace the O2 sensor because of age). Best (and most likely thing) that will happen is that we saved you 700.00

 

 

Either way a win win.

 

nipper

 

Thanks for all the help!

[OB99W]

Before changing an O2 sensor or cat, you might want to consider:

 

When was the engine oil last changed? With all the misfiring that had previously occurred, the oil could be significantly fuel-diluted. That can sometimes cause P0420 (P0430). If the oil was changed after the timing was corrected, then this isn't likely.

 

It may be worthwhile checking for exhaust air leaks. If the misfiring led to any afterfire ("popping" in exhaust), there may be damage at a joint or elsewhere.

 

Otherwise, as already suggested changing the front O2 (A/F) sensor in the affected bank is probably a good first step, followed by the bank's front cat if that doesn't do the trick.

[dbullen]

Before changing an O2 sensor or cat, you might want to consider:

 

When was the engine oil last changed? With all the misfiring that had previously occurred, the oil could be significantly fuel-diluted. That can sometimes cause P0420 (P0430). If the oil was changed after the timing was corrected, then this isn't likely.

 

It may be worthwhile checking for exhaust air leaks. If the misfiring led to any afterfire ("popping" in exhaust), there may be damage at a joint or elsewhere.

 

Otherwise, as already suggested changing the front O2 (A/F) sensor in the affected bank is probably a good first step, followed by the bank's front cat if that doesn't do the trick.

 

Thanks a lot, oil was changed after dealership fixed the issue. I don't remember hearing any popping noises at all, just a bearly noticable misfire at idle. Need to have a provincial inspection done friday, will have the dealership take a peak. I'm really hoping it's not the cats.

[screwbaru2]

I haven't read the whole thread but if nobady mentioned it "Just at idle the rpms flucuate " is often time a vacum leak. Check all the vac hoses.

[scb10s]

First time post; (2003 outback H6) In reading through the thread above, ShawnW pointed out that compressing the tensioner in the vise too fast could cause damage to the piston/body of the tensioner. I was of the understanding that the early H6 engines used a oil/ratchet type tensioner ? Possibly not but, if they do, is there a way to release the ratchet and compress the piston so a used tensioner can be reinstalled? The tensioners on my 2003 outback have a allen headed screw at the base of the assembly and what appears to be a drain port connected to it. Curious if this is to drain trapped oil or allow access to the base of a possible ratchet mechanism?

 

Thanks, scb10s