Okay. Things are looking up...but I'm stuck again on my next course of action.

My '02 had that turbo pulsing issue...at WOT, the turbo was "pulsing" in 3rd through 5th gear, resulting in a jerky acceleration which at times made it impossible to even make a pass at 70 MPH. The whiplash was getting a bit annoying too...

So I tried the grounding mod. Strong results overall (i.e. brighter lights, stereo response...), but the problem persisted.

I then proceeded to the Subaru garage for a diagnosis. The tech there seemed to think it was a possible failing coil, and further investigation led indeed to a cracked coil. This was replaced, and everything else checked out.

...and the issue is still there. Currently, things avae improved a bit. 3rd gear is strong at any throttle position. 4th and 5th are as bad as ever. I spoke with Vishnu yesterday (I'm in the market for a re-flash), and the thoughts there could be a sticky wastegate actuator or leaky BOV (best case...), or possibly a dying turbo (worst case...). Other suggestions are the spark plugs need replacing, and the K&N filter oil could be messing up the MAF sensor. (The airbox is fully intact, with the snorkus removed, and is sealed off to the fender well.) I would tend to discount the K&N theory, since it was doing this before I added it. Plugs could be possible, but were examined when the coil was replaced, so I'd tend to shy away from this too.

ANy thoughts? Does anyone have experience in anything like this? I'm still learning how to work on this car myself, and I'm willing to try anything, but I'm not near the ability level of pulling and examining the turbo. What to do? I don't really want to go back to the local garage, since they've already missed the boat once, and I'm not under warranty anymore (63K mi).

Thanks in advance, guys. If there's anyone near the southern New Hampshire area that would be willing to give me a hand in person, I'd appreciate it as well. Have car, will travel...just not too fast. =)

 

You just feel the surging or do you see it on any of the dials as well? Way back when I had the classic hesitation problem and you'd the the tach climb and then stutter, climb some more and then stutter some more, etc. I went to one of the better local dealerships and the tech put his magic box on my car and voila (between that and a homemade grounding kit) all was better.

jason

 

I just feel the surging at this point, but it's very severe. I don't have a boost gauge on the car yet, and there's not a visible movement on the tach or speedo. But it's enough to move me in the seat. It feels like a boost or fuel drop that cycles twice a second. The garage had me hooked up to the box, and I wasn't throwing any CELs at all.

 

What gas do you use?

jason

 

It sounds like an intake leak or a boost control/fuel problem.
Without a boost gauge, there is no way to know if you are possibly hitting boost cut.
Also, if you are using cheap/low octane gas this could be a problem.
If one dealer can't figure it out, try another one..it is possible that it may be something glaringly obvious to someone who has seen this particular problem before.

Did you buy the car new? Have you or anyone else ever tried to install a boost controller?

 

Thanks for the responses...I appreciate it.

I've run nothing but 93 octane since I bought the car, but the dealer had warned me to "switch to only hi-test" when he fixed the coil, so the last owner might not have been quite as judicious. (I bought it 5500mi ago) I have a feeling the previous owner might have had a boost controller on there somewhere, but I'm unsure. (There were a set of Altezza tails on it and some aftermarket 17"s, as well as marks from where there had been a front strut tower bar, and possibly some Morettes or an upgraded grille of some sort, so anything is possible...) I bought it from a dealer used.

I may try to hit another dealer...it'd be nice if there was one around here (Southern NH) that was familiar with performance tuning. I'm waiting for my boost gauge to arrive in the mail so i can install that as well. What are my best options for looking into the intake leak possibility in the meantime? Are there any other things I could do before paying for another diagnostic from a dealer?

 

Pruven Performance isn't very close to you but they have experience tuning subies and EVOs.

--
0==WW==0
"…axles of evil…" - george w. bush

 

It is very possible that if there was a boost controller on it, when the hoses were put back on the turbo they were put back on wrong and you are hitting boost cut and that is causing your problems.
GET THIS CHECKED AS SOON AS POSSIBLE.

 

$0.02:

you said you noticed no movement in the tach.. that makes me think its the turbo or some exhaust component. if it were anything on the intake side of things you'd most definately see some rpm spikes to go with your surging.

 

If he's hitting boost cut he'd notice the CEL and have a way more dramatic experience, don't you think?

jason

 

Yeah...definitely no CELS are being thrown...Although it does feel like I could be hitting boost cut. Is is possible that this could also be caused by any of the afore-mentioned possibilities, like a sticky wastegate actuator, or would any boost cut throw a CEL no matter what?

Is there a good diagram that I can grab that will give me the schematic to check the turbo hoses?

 

My car never threw a CEL when I hit boost cut....I don't think....been a long time since I had to worry about it....
There IS a diagram out there....I'll have to see if I can find it....

DJ Catchem...you may want to see if someone in your local area can help...are you a member of the 'other' board? There are MANY Subie people in New England who would be more than happy to help you, I'm sure.

 

Cool. I appreciate the help. If you have that diagram, I'll start there.

The 'Other' board? Apparently not. =)

 

I'm almost positive I know what it is. When I took my manual boost controller off of my 04 and put the stock lines back in I had the same problem. The problem ended being in the factory boost control lines. Apparently when I took them off the car the came apart and I put them back together incorrectly. I would get the same thing, in 3rd gear or higher, when I gave it gas it would build about 10 psi of boost then spike to 15, then drop to 10 and back to 15. It did this at the rate of 1 oscillation per second or so. I change the boost control lines around and it was fine. Maybe if the past owner had a boost controller on the car he put these lines back together wrong. They should be in a T configuration. The line should come out of the controler the terminate at the T perpendicular to the other two outputs. Then one end should go to the turbo and the other to the wastegate, like this.
WG
l
l
l
l-------------------Boost Controller
l
l
l
Turbo

Hope this helps. If it doesn't disregard this ramble.

 

That sounds exactly like what I'm experiencing. I'll take some time this weekend to dig around a bit and see what these lines look like. Sounds like as good a place to start as any.

Thanks for the help!