So, I'm still working on this '05 WRX; I Pulled the turbo out and the turbine does spin and doesnt have any play in it. Though, the car does have ~150k and the turbo needs to be rebuilt, but thats a different project for a different day.

 

Put the turbo in and it feels like there is a little boost now but, it bucks at you right around when the turbo would put out boost (around 3 - 4k on the tach). Any ideas?

 

i was going to suggest a tune up. but im thinking it wont help much..

 

 

Ideas?

 

 

-Justin

If the turbo is good then it will build at least about 6 psi because that much is needed to open the wastegate. If it doesn't build 6 psi then there are exhaust leaks before the turbo, clogged up exhaust (bad cat's), or the turbo is bad.

 

It sounds a lot like what I've experienced with bad catalytic converters.

 

GD

any idea on the bucking?

 

-Justin

any idea on the bucking?

 

-Justin

 

I believe that's what GD was referring to:

 

It sounds a lot like what I've experienced with bad catalytic converters.

 

GD

 

I'd also be looking for leaks - likely around the turbo inlet. They tear where the hose clamps on the turbo. If you're getting un-metered air into the engine, it could cause issues.

 

Also, the coil on plug (CoP) connectors were an issue on older WRX/STi models (EJ20G)...I'd look it up on NASIOC to see if they're still a failure point. The connector cracks and causes misfires, IIRC.

 

Are you getting the CEL on when the 'bucking' occurs? That would help diagnose, too. Some auto parts stores read codes for free (Autozone).

 

GL,

Td

Edited August 27, 201213 yr by wtdash

Are you getting the CEL on when the 'bucking' occurs? That would help diagnose, too. Some auto parts stores read codes for free (Autozone).

 

GL,

Td

 

 

No CEL :-(

 

 

I even plugged it in for giggles to be sure. Kinda odd.. i thought...

 

 

-Justin

spilt blowoff valve tube or intercooler leak or stuck blowoff valve

Can it get over 3-4,000 rpm at all? If not, it may be valet mode.

 

Jacob

oh, It'll still haul butt..

 

I bypassed the wastegate to leave it closed.. i had a LOT of boost. I put it back on, still have a bit. but it bucks right when its supposed to boost.. either senerio :-/

 

 

would a faulty coil over do it?

 

 

-Justin

oh, It'll still haul butt..

 

I bypassed the wastegate to leave it closed.. i had a LOT of boost. I put it back on, still have a bit. but it bucks right when its supposed to boost.. either senerio :-/

 

 

would a faulty coil over do it?

 

 

-Justin

 

How did you bypass it? With a bracket? The wastegate could be opening early. Is the arm hooked up ok?

 

It sounds like a vacuum/boost leak, in that case.

 

Also, if you don't know the difference between a coil and a coilover, then you should take it to a shop:)

 

Jacob

.....

Coil Pack.

 

 

I just pulled and plugged the vacuum going to the waste gate. Had the boost - only amplified the bucking...

 

 

oh, and to add. It starts up first crank and doesnt idle rough at all..

 

 

 

-Justin

Edited August 29, 201213 yr by crazyman03

have seen the wastegate valve get sloppy and leak and bypass and diafram get weak in wasgate pot sounds like lean to me or tracked plug or tracked wire or valve addjustment witch is a pain took me 12 hours to addjust the last one had to remove heads and indavidualy ajust valve hight to get it right was realy missing when hot and idleing poorly hot but ok when cold got worse as it heated up the valves were at 0.08 - 0.10 and should have been 0.20 0.25 mm made a hudge differance in how it ran

aaaannnnd now I have no bucking and no/late boost ?????

 

I havent touched it, decided to take it for a spin to show someone what it was doing and had no bucking

 

Car

 

 

-Justin

Running lean is REALLY bad for a turbo engine. If a turbo engine leans out you get holes in the pistons and/or rods through the block. I'm thinking it's leaning and the ECU is cutting everything to avoid rearranging the scenery under the hood. (pistons goin "I can see the light!")

 

Fuel pressure could be low. Filter could be clogged. Injectors not spraying properly. Maybe check fuel trims and see if that offers any clues.

you have a plugged up cat most likely. check if the up pipe is plugged up.

 

my forester (non turbo) would buck and surge under throttle and the front cat was plugged up.

have you modifyed the intake boot to the air fillter at all ? cold air intakes somtimes cause problems is all the pcv plumbing in proper place all vacume lines and hoses in right places stuff like that

also, it's buck/surge was extremely rythmic as the mass air/computer tried to figure out why there was an inconsistancy between throttle position and mass air readings.

Sounds a little like the problem I just had with my rally car (02 WRX engine). Tried all kinds of diagnosis. No CEL codes. Boost was good. EGT was good. Wide band read good numbers. Turned out to be the MAF sensor. If I took the car out for a 3 or 4 mile run when cold it would act up the same way. When I got back to the garage and let it set for 1/2 - 1 hour, then took it out again it ran fine (everything was good and hot, up to full temperature). Finally discovered it was the MAF sensor by swapping the one out of my sons car. Nothing pointed to it being the problem, but it fixed the problem.

Edited August 31, 201213 yr by rallynutdon

well, it boosts and boy doe it haul..... the mail.

 

turns out, it was the MAF, thanks "rallynutdon". pulled it off and it was all kinds of black. Also, he was running 87 octane... :-/. Put 91 in it and that cleared it up almost immediately. I'm going to be putting a Turbo timer in it and a boost gauge tomorrow.

 

I was talking with a buddy of mine, I still think it should have a bit more turbo pull. He thinks i'm crazy. We'll find out tomorrow if its boosting ~13ish lsbs.

 

 

thanks everyone!

 

 

-Justin

This:

Also, he was running 87 octane... :-/. Put 91 in it and that cleared it up almost immediately.

 

87 octane = detonation = ECU cuts ignition timing and boost to protect the engine from growing holes in itself.

 

Dirty MAF certainly wasn't helping anything though.

This:

 

 

87 octane = detonation = ECU cuts ignition timing and boost to protect the engine from growing holes in itself.

 

Dirty MAF certainly wasn't helping anything though.

 

Haha, nice. Holes are bad.

Just a little bit.. yea. sadily.

 

 

-Justin

Subaru's don't need turbo timers. The coolant circulates via convection after the engine shuts down - that's the point of the upper water tank - to keep the coolant level above the turbo so convection will occur. Timers are to run the engine and cool the turbo before shutdown to prevent the oil from overheating inside the turbo. Subaru's also drain all the oil out of the turbo due to their high mounting location.

 

So it's really pretty much useless on a Subaru and makes you look silly to anyone that knows the cars.

 

GD

Subaru's don't need turbo timers. The coolant circulates via convection after the engine shuts down -

 

So it's really pretty much useless on a Subaru and makes you look silly to anyone that knows the cars.

 

GD

 

hmm.. neato! I didnt think of it that way.

 

At any rate, I've already ordered it.

 

Now, My new problem: Kid wants a "bigger" turbo, Instead of rebuilding or replacing the OEM, and a BOV. *shakes head*.

 

Basically, hes going through ebay, checking the compatibility list and seeing that they all fit - Not realizing they arent all "Plug and play", or even what might need to go into "upgrading" just so the car will work with the new turbo..

 

 

-Justin

Bigger turbo means more lag. I'm guessing what he means is he wants bigger boost.

2 words: Cobb AccessPORT. done. http://www.cobbtuning.com/Subaru-AccessPORT-p/ap-sub-001.htm

You'll need that to make any real use of a larger turbo anyway since boost levels are kinda set by the ECU on these. I think there are some ways to fool the ECU but those usually lead to hole ----> engine territory.

Yea.. There was that too..

 

I guess the other real big problem is that he's spending mama and grandpas money.

 

I got it running, did some understandable upgrades and to make mom happy so he can drive his car again. But! Since he's not funding this little project - no.

 

 

-Justin