Sounds like the boost control solenoid is not functioning (and they'd have removed this to cure overboost) and you're running in limp mode (.6/.7 is where the wastegate opens without the solenoid to bleed air away).

Check the pipes and connectors.

Richard

[Edited by dowser - 11/1/2001 12:12:10 PM]

 

Just a note to back up whats already been said....
Sounds as though your car automatically goes into run safe mode (low boost) as you continue to hit overboost 1.4Bar way too high on non chipped car. The ECU will shut the boost sol down for the remainder of that journey until you key off.
I would suggest you don't have the restrictor in the right place or don't have one at all.
This would cause massive overboost.

Just to add, you may want to check that you have a little brass restrictor in the vacuum hose located between the T-Piece and the compressor outlet spigot on the turbo. You sshould just be able to feel it within the hose by pressing around a bit. If you have one there, chances are it may be the wrong diameter hole.
If this is all present and correct then I haven't got a fudging clue....Try and get Bob Rawle's advice or worst case a dealers

Jacko

[Edited by Jacko - 11/2/2001 3:53:27 PM]

 

Anyone come accross this.....Had the car (MY99) serviced yesterday, and mentioned to the dealer that it was overboosting to about 1.4 bar. When i collected the car last night i gave it a bit of lash and it seemed o.k. (1.0 Bar). Tried again later in the evening, and now the boost hits 0.6 bar and stops there. This happens in every gear all the way up the revs.........Please help!!!! as it's a 150 mile round trip to my dealer.

manny

 

Dowser,

thanks mate, i will check all the pipes, although i have just sprayed some brake cleaner into the pipes and all seemed well for a minute or two (boosting to 1 bar) then it droped back to 0.6 bar!!!.....Is this familiar to anyone?

 

As doswer said really

Check your pipes for leaks, kinks and poor connections. Then have a look at your solinoid and its connections. You can disconnect your solinoid and run wires from your battery (two people req) and touch on the soliniods connectors, you should hear the solinoid clicking. Also ensure you have the pipes fitted in the right places if you have removed them to clean them.

The only problem I have encountered with spraying brake fluid into the pipes is problems starting the damn thing afterwards.

Hope this helps.

Neal

 

Right....checked all pipes for leaks to no avail. Cleaned solenoid and MAF sensor and all pipes, this cured the underboost, but led to massive overboost again (1.4 Bar) for a minute or two, then the car started to underboost to only 0.6 Bar again and won't go any higher. I then checked the oil when the car was cold it is about 2mm under the top mark, is this too much??? Help.....i'm beat!

 

Did you have a restrictor in the car?

Maybe the dealer has changed the restrictor to restrict boost?

Mark

 

Jacko,

Thanks for the advice.....There is a restrictor in there but i have no idea what diameter it is, your diagnosis seems spot on to me, it is as if the car goes into some kind of safe mode at 0.6 Bar. I will have another go this weekend, failing that its back to the dealer on monday...Once again thanks to all who have posted, and i will let you know how i get on

manny (MY99 u.k)

 

Manny

I continued to have overboost until the oil was just over the lower level. Even when the level was at at halfway overboost still occurred. I found the trouble was if the car wasnt on a flat surface the oil level reading isnt accurate.

Again drain out the oil until just above the lower level. Clean out the pipes and give it another go.

I didnt experience the underboost problem but my car is an early MY98 so the set up has changed.

Cheers

Neal

 

How about checking the ecu for error logging?

It may be the ECU going hyper over a reading from a sensor...

hope this helps in some way...