MB engine overboost.

["Lowe, Jonathon, LOWEJD" <lowejd@btlip12.bt.co.uk>]

Hello,

Its Joe Lowe again with the '89 MB Ur quattro.  Some of you might remember 
that I wrote back in August asking the question why my engine gave me over 
boost and then cut out.  I got a satisfactory answer and spoke to BR 
Motorsport on the matter, confirming that it is known as "MB warm up over 
boost".  I also found out that back then there is was no cure for this 
problem.

Well over the past month or so I have been experiencing over boost on a few 
long journeys.  The over boost has happened on approx 50% of the long 
journeys and has either been on the journey to or from the destination but 
never both.   The car has been hot and running for between 30 minutes and an 
hour when the problem manifests itself.  I'm unsure if the air temperature 
has suddenly dropped causing this to happen.  It mainly happens if the 
engine is at 3000 rpm or over and the throttle is being opened more than 
half way.  Some times I can feel the extra urge the over boost gives at at 
around 2500 rpm and if I back off the throttle the engine will not cut out. 
 I have had the situation were I get over boost and the engine cuts I have 
backed off the, engine comes back to life, I have put my foot down again but 
only lightly and I get over boost again, this will repeat itself 3 or 4 
times and then it will be fine.  This problem does not affect the whole 
journey either.  As you can imagine it is embarrasing for me, uncomfortable 
for my passangers and dangerous for other road users. So please if there is 
anybody that can help I would really appreciate it.

Apart from this the car is wonderful.

Regards,

Joe Lowe.