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valve lash or bad injectors


upshiftn

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Although I've read a bunch of threads covering these items, I'd like to get opinions from some of the more experienced on here... not mentioning any names but you know who you are ;)

 

05' leg gt - 5 spd, basically stock. 90k miles.

 

My symptoms:

 

1) no CEL

2) slightly rough idle, nothing terrible tho (since purchased 2.5 yrs ago)

3) slightly noticeable stumble for first few minutes only when coming to a complete stop (rpms approaching the 800-1000 range)

 

haven't done a leak down test but intend on doing one. cleaned maf sensors and have done sea foam in the past. neither changed the rough idle at all. the stumbling is a more recent symptom (last few months). any input is greatly appreciated!

 

Thanks in advance

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I had a slightly similar issue. I had a stumble when coming to a stop (similar RPM) that turned into the car infrequently dying after coming to a stop from high speed. It turned out to be a burnt valve. Hopefully you don't have the same.

 

See post #24

http://legacygt.com/forums/showthread.php/build-critique-and-questions-213763p2.html?highlight=build+critique

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You said you had your subaru shop take a look to see if you were experiencing valve lash but said they didn't think that was the case. What does it take for them to test for this? I've been having to make repairs monthly since fall and my shop mentioned my symptoms were most likely related to this but they hadn't officially diagnosed it yet. Just trying to have an idea of the scope of this potential repair before I head down that road if needed..
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Try the easy stuff first. Change your plugs, clean MAF, and reset ECU.

 

Agreed, definitely try other options first. The way to check valve lash is to pop the valve covers and remove the cams. This involves taking off the timing belt. If you wanted to get your timing belt done a little early, it would only add a few hundred bucks. Otherwise, you're looking at $500-$1000 in labor just to look.

 

You could try getting a stage 1 etune from someone like Cryo. Getting off the stock map is never a bad thing.

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Have you done your 90k? 60k? Plugs are part of the 60k. Also the dieing could be a vac leak somewhere. Have it smoke tested to check for vac leaks.

 

-Mike Paisan

 

http://www.pbase.com/paisan/image/153798190.jpg

Maintaining, Modifying and Educating TriState Enthusiasts since 2001.

Like us on Facebook! | E-mail: sales@azpinstalls.com | 725 Fairfield Ave | Kenilworth, NJ 07033 | 908.248.AZP1 (2971) |AIM: AZP Installs

"Race Tested, Enthusiast Approved!"

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You could give Alberto at Motive Auto works a call and have him do a boost leak test for you. Great guy, great service. In woburn.

 

he is my shop guy ;)

 

I'll consider doing the plugs but I vaguely remember him saying my plugs were "fine"... not entirely sure what needs to be done to test if they're good (check the gaps?).

 

I also will need to do my timing belt in about 10k miles so i'm thinking about doing all of this this summer (at the same time).

 

I'll have him do a vac leak as well... good thought for the stumbling.

 

MAF was cleaned 2 yrs ago.. didn't change anything.

 

i think the tune will be my last option but am definitely aware that could help things.

 

thanks

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he is my shop guy ;)

 

I'll consider doing the plugs but I vaguely remember him saying my plugs were "fine"... not entirely sure what needs to be done to test if they're good (check the gaps?).

 

I also will need to do my timing belt in about 10k miles so i'm thinking about doing all of this this summer (at the same time).

 

I'll have him do a vac leak as well... good thought for the stumbling.

 

MAF was cleaned 2 yrs ago.. didn't change anything.

 

i think the tune will be my last option but am definitely aware that could help things.

 

thanks

 

Two years? :lol: I do mine twice a year. It takes a minute, just make sure you reset the ECU too (you can remove the negative battery terminal while you clean the MAF to do this). And a tune won't cure a stumbling idle. Fix the issue at hand first.

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ok will do.

 

some people on here mention that factory maps are kinda wacko and a tune can smooth things out. i don't believe this is the reason i have the rough idle but i feel it could be a potential solution. to be completely honest, and my shop was the first to say it, i think it's going to end up being valve lash as it does seem to feel like a slight continuous miss fire...

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update:

 

CEL came on yesterday. Turns out later in the day I got it not to come back on after securing the fuel cap however understandably this may not have been the cause. My question is can the CEL go on and off due to valve lash or will it stay on once it's triggered and fully out of spec for this potential situation? My immediate repairs will include: change of spark plugs, new o2 sensors (maybe), leak down test/compression test, and of course check for codes first. I have a hunch it'll be o2 sensor related because from my exp these can cause the cel to come and go and i always give the fuel cap 3 clicks after a fill. Repairs scheduled for next week - will update then. mean while, rest of ya'll cross your fingers it's nothing worse at the moment. (wallet's getting pretty light).

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update:

 

CEL came on yesterday. Turns out later in the day I got it not to come back on after securing the fuel cap however understandably this may not have been the cause. My question is can the CEL go on and off due to valve lash or will it stay on once it's triggered and fully out of spec for this potential situation? My immediate repairs will include: change of spark plugs, new o2 sensors (maybe), leak down test/compression test, and of course check for codes first. I have a hunch it'll be o2 sensor related because from my exp these can cause the cel to come and go and i always give the fuel cap 3 clicks after a fill. Repairs scheduled for next week - will update then. mean while, rest of ya'll cross your fingers it's nothing worse at the moment. (wallet's getting pretty light).

 

 

First why don't you see what the CEL code is for. That will give you a good direction to go in.

 

-mike

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First why don't you see what the CEL code is for. That will give you a good direction to go in.

 

-mike

 

correct... but i know the plugs haven't been changed out since i've owned the car (2.5 yrs) and that might take care of my separate issue of a shoddy idle. codes will obviously be read first but hoping it's nothing more than an OCV replacement or oxygen sens.

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code was P0546... exhaust gas temp sensor circuit high bank 1. So its an o2 sensor. phew. easy fix. will also do the spark plugs while im at it and next week the leak down/compression test.

 

 

Um no, that's the EGT sensor. Do you have an UP in the car?

 

-Mike Paisan

 

http://www.pbase.com/paisan/image/153798190.jpg

Maintaining, Modifying and Educating TriState Enthusiasts since 2001.

Like us on Facebook! | E-mail: sales@azpinstalls.com | 725 Fairfield Ave | Kenilworth, NJ 07033 | 908.248.AZP1 (2971) |AIM: AZP Installs

"Race Tested, Enthusiast Approved!"

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all looks to be good now... replaced the resistor, taped her back up a little better this time.. did a proper ECU reset. hopefully we're good to go. thanks AZP and others for bearing with.

 

quick question tho: anyone know how deep the resistor needs to be seated?

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