LG John

Hi guys/gals,

My car is being a pig the last 24 hours and because of it I've had to miss a meet I was really looking forward to.

The spec:

MY99, recently serviced with 30k (hence plugs) having been done in the summer.

It has a full scoobysport decat, standard air filter, STI V intercooler with samco hoses.

Tek2.5 remap and a dawes to control the boost set at 1.25bar.

In the colder weather the boost has been nearer 1.3bar but its usually been very well behaved until now...

Driving along the M8 yesterday I floored it at about 85mph and the boost smacked round to 1.4bar before dropping to less than 1.0bar and rocking in between It finally settled in and around 1.19bar which is below what it usually would. Further tests showed this overboost and lack of boost control through the gears. I spoke to John Banks last night and following his advice removed the dawes and checked and cleaned it. All the intercooler pipes seem to be in place and secure but the car showed the same problems again after all this I've turned the boost down for safety but this isn't a cure.

Does anyone have and ideas or suggestions? Please remember I'm not a mechanical type of person so you'll need to explain things in simpleton talk. I really don't want to chuck it at nobles just to have them do £300 worth of problem finding to find its something small and simple (which I really hope it is!)

Not sure if its related but the car seems to be popping (especially pops) and banging more than usual when coming off the throttle. Furthermore, the engine sounds a little rattly, but then, I'm now super-paranoid so it could be the creamiest V8 on the planet and I'd still think something is wrong

Cheers

brickboy

A couple of thoughts which I hope might help -- is the wastegate actuator linkage moving freely? They do get exposed to all the road sh*t & salt etc, and if the linkage gets sticky then boost control will not be progressive.

Try and give the linkage (where the actuator arm hooks onto the wastegate lever) a hosing with WD40 (but try not to cover the actual actuator unit or the lube might get into the actuator diaphragm).

The other thing is, if it seems to be popping / banging more, is the dump valve OK? What DV do you have? Can you swap it?

Good luck,

Craig / brickboy

john banks

When you turned the boost down what is it doing now? Is it peaky again?

iainalpine

hi saxo. good luck with the car mate, i no what its like. going by what you have posted it sounds like something daft but trying to find the fault is sometimes not the nicest of jobs.
have a good new year
iain

T-uk

did Sam's EVO not start doing something similar at K/hill?,he found it to be the dawes spring sticking or needed stretched or something.

john banks

Bring it over this afternoon and I'll have a look at it Kenny.

LG John

Off to see Dr. Banks

Cheers John

robinH20MRV

Hi mate,

please let me know what the problem was, i think it may be the dump valve, i had one that failed, and the problem sounds alike

best of luck!

cheers robin.

john banks

Cleaned the Dawes - the ball was sticky from an oil coating. Also the boost gauge was showing spikes that were not there according to <250ms sampling from Delta Dash. It was also wavering during held boost periods when the MAP sensor had a rock steady signal. So Saxo's car is quite well really

LG John

Yup, seems to have been mainly the boost gauge that was problem as John was happy with things on Delta dash. Coming back she was showing between 1.1-1.2 bar with two up which is no where near what the Tek2.5 can run. That said it still went very well and clocked a 65-105 using my previous methods of 7.45s with an additonal person in the car......in short I think the boost gauge is lying!

I've had a useful lesson in dawes maintance and also a jaunt in Johns car. It never going to play with Andys car for 'that pinned feeling' but the speedo went totally nutts when on boost I have to say my brakes felt gash after those AP jobbies...it was like they wanted a weeks notice that I'd like to stop

All in all, I'm a little gutted that the gauge doesn't seem accurate anymore as the last time it and the delta dash were both showing the same thing and I'd always know what the boost was up to.

John...thanks for taking the time to help today. I feel a lot better that its had the laptop into it without showing any problems.

cheers

btw....see the ctr thread