[urq] suddenly lean again

[fdekat]

>  Sometime last year I had a problem that I asked for help on but I
> regretfully did not keep the replies and the problem went away and I
> never found out a cause. Well it has started again. The symptoms are as
> follows:
> 
> If I accellerate hard in any gear it pulls like a train and the air fuel
> meter shows (as expected and desired) a rich mixture. When I lift off ,
> change up and re-apply the accellerator the power has gone and the
> mixture has gone lean. If I were to keep my foot down this condition
> would remain. If I lift off and then reapply the accellerator then the
> power returns, the mixture returns to rich and it would  continue to
> pull until I ran out of revs. If I keep my foot down instead of changing
> up the mixture remains rich so it does not appear to be a case of fuel
> starvation. 

I've had a similar problem, but I have no air fuel meter so never noticed a
mixture change. I noticed the problem with the same lack of power symptoms.

Pulling hard, upshift (with quick close of throttle), then back on the
throttle hard, and NO power.  Interesting enough though, boost gauge still
showed plety of boost pressue when this happens, but still no power.

But put in clutch, rev motor, let out clutch, and now lots of power.

I put it down to the turbo being 'unspooled', and changed my shifting
technique so that I keep the throttle partly depressed when shifting, and not
'snapping' it closed. (Although plenty of boost makes that 'unspooled' theory
suspect).

Unrelated, I have changed from the original ECU to a complete MAC11 system
(harness, ECU and all related bits), wihile retaining the stock urq fuel
metering unit.  Throttle switches tested operational to the ECU connector.

No change!  So makes me think the problem may be something about the fuel
metering unit.

I too will be interested in what your solution is!

Regards,

=Frank de Kat=