Ive noticed when Im powering hard say up a hill, the power from the turbo seems to come in waves, not massive jolting waves, but not smooth, you can feel it almost pulsing/waving as its gaining speed, it still accelerates very well but you do feel it somewhat holding back and the only way i can think to explain it is waves/pulses of power... any ideas what this would indicate or what i can do to rectify this
thanks

 

1993 to 2010 UK-JDM modded/standard

You getting the ??????

 

Sorry didnt thnk of that

its a std 1999 Turbo only mod is stainless steel exhaust...oh and STi intercooler.. so allmost std..

 

sounds like it could be an actuator problem struggling to hold boost.

 

thats good, it doesnt sound expensive, where abouts is the actuator ? could I test it be disconecting it ,or will that stop all boost ?
thanks

 

The actuator is the round thing attached to the turbo mate it will have a rod coming out the back of it not sure how to test it though!

 

It might be the actuator but it might well be something else. Probably more likely to be overboost than the actuator itself being damaged.

Can you confirm for us whether the car's been remapped or otherwise modified in any way, and can you also (if you have a boost gauge) tell us exactly how pronounced these "waves" are, and what sort of repeat frequency they have?

If by "disconnecting the actuator" you mean removing the boost control pipe from it, do not under any circumstances try this.

 

You could try cleaning the boost control solenoid and checking all the vac/boost pipes for splits/cracks/insecurity.

Have you done/had a oil change recently??

 

Mine split a hose to the actuator recently.... and the symptoms were similar to yours + 2 bar of boost !

HTH

dunx

 

Maddog was hooning at the Nurburgring and a boost pipe come adrift. You can guess what happened a few seconds/minutes after that........!!!

 

The cars not been remapped, the only mods I have are a stainless steel cat back exhaust, and a STi intercooler.. i had a PPP ECU on it, but removed it after a few months, and went back to std ecu.
The waves are smooth, not jerky motions, you could to be honest live with them, but I know they are there and if i can cure them id love to, its only under preasure like when I power up the hill on route to Farnham, its the Basingstoke rd, the hill that leads into Farnham, its quite steep, but the car gets into this pattern of pulses, where its powering all the way, but you definately feel the waves/pulses in probably 1 second gaps, which dissapear once you level out and back offf the power..

thanks

 

I did a oil change myself and filter less than 1000 miles ago, 10w 40 oil, I will try cleaning the boost control solenoid.. is that on top of the rocker cover ?

thanks

 

No, BCS is mounted on the O/S inner wing, looks like this



It's the silver cylinder in the center of the pic. Flush it through with brake.clutch cleaner.

If you over filled the oil that can cause boost issues

 

bat, OP has 1999, so he'll have the later 2 port system.

 

Doh, cheers Joz

 

I can only find the photo embedded in a document and I can't "copy it's location" so as to be able to embed it in a post. The photo used to be readily available on the net

 

http://www.cobbtuning.com/info/?ID=3482

 

I think my 2003 sti is doing something similar

if anyone knows for sure I would be glad to hear it.

meanwhile, I too will check the pipes from my turbo to the solenoid for leaks.

may be worth simply replacing them as I would not expect them to be expensive.