The_Judge

Good afternoon! I'm still new to this, so don't rely too heavily on my comments...

A slight contradiction there, me thinks. If it's overboosting, then that is a fault. Surely it would have shown up on their diagnostic equipment...?

For those symptoms, overboost is a reasonable assumption, I would have thought. Or at least something that could trigger fuel cut.

I wouldn't have thought the symptoms you have described would be synonymous with lambda failure symptoms. When you boot it, the car goes into open-loop mode, and the lambda sensor ain't doing a great deal. Your MAF and engine maps take over. Do you have any other symptoms that could indicate MAF problems?

Were they able to recreate the problem?

So you don't have a manual boost controller or bleed valve? And you haven't modified the restrictor in the pipe between the turbo and the wastegate? Are all the pipes OK?

You wouldn't have thought so! But then there's a difference between a fault that you could have influenced with modifications, and a fault that's "naturally occurring". So in the case of the latter, in theory, overboost could occur at any time.

Can you borrow one off someone temporarily?

As long as you remember that the problem is there, and you drive sensibly (ie, no flooring it in high gears), then yes, I'd say it's safe to drive. As a comparison, I fitted a boost controller a couple of days ago, but did a bit of a bodge with the piping until the proper stuff arrived (today). Took it for a spin yesterday, floored it in third, heard a "pop" from the engine bay, saw the boost gauge go mental, pulled over, and noticed one of the pipes had popped free. Drove it back to work very steadily. But then I did have the advantage of a boost gauge. As long as I didn't floor it, the boost never went above 7psi, so no problem.

Possibly. I had a Hayward & Scott (open neck with splitter) downpipe fitted on Monday, before I fitted the boost controller, and noticed my max boost had increased by a couple of psi. Don't know whether it's a fault, or whether it's to do with the combination of the neck of the downpipe along with the removal of the cat. With the boost controller fitted though, no problem. Adjusted it to what I wanted it to be, not what IT wanted to be.

Hope some of this has helped. Regards,

Ade.

[Edited by The_Judge - 10/2/2003 3:26:28 PM]

Keigo

I just took my MY98 UK Turbo for a diagnostic test at my local Subaru dealer. They did not find any fault with it, but told me that it could be overboosting.

The synptom was the car losing all its power at about on throttle at 4000rpm upwards, generally in 3rd or higher gears. I posted earlier, and was told it was probably a failed lamba sensor, but according to the dealer, the lamba, MAF, all the sensors are working just fine. They even took it for a on road test with the equipment.

The only engine mods I have at the moment is decat centre section and backbox, plus K&N induction kit, and a Forge DV. Surely it wouldn't have any overboost at this level of mods? I'm still waiting for my boost gauge (from the group buy with Voodoo) to arrive, but it would be another 5 weeks before I do, so I can't tell if it is overboosting.

The major question if it is overboosting, is "Is it safe to drive it?"

Can anyone shine anymore light on it?

P.S. I will be putting on my decat downpipe this weekend, so I don't know if the problem is going to get worse with it... we'll wait and see.

Aintbroke dontfix

Check the pipes and jubilee clips around the wastgate actuator, top left of engine. I had the same problem, and found 1. a small split in the pipe which was acting like a bleed valve and 2. one of the jubilee clips was bent so when tightened didn't make a seal so again natural bleed valve. Could be as simple as that.
Good luck.