Re: 86 5kTQ breakup/tuning problems

[Alan Cordeiro <cordeiro@avlna.com>]

> 
>  
> I've been reading the quattro list for a while, and hope there's somebody
> who can help shed some light on what's going on here.
> 
> I've got a 86 5kTQ that has a computer modified by Total Audi Performance,
> or maybe I should say screwed up by TAP.

> 
> Finally, Anita at TAP said that she had shipped me the wrong wastegate
> spring, and that I was running way too much boost. (I was dumb for not
> having a mechanical guage on it right from the start).  
>

You are lucky you did'nt "pop" your intercooler.

> Now, with the correct spring and the MAC-11 computer, it runs about 10PSI
> boost by the mechanical guage and only reads 1.3 or 1.4 bar on the guage 
> in the dash.  Low RPM power is better than stock, but I'm still not getting

> Charlie Smith   charlie@elektro.cmhnet.org  614-471-1418  
>                   Columbus Ohio   USA

TAP has put in a voltage limiter just after your pressure transduce output.
This is why the guage ( which converts the output 2.5 volts = 1.0 bar ) 
never reads above 1.3 bar. I would strongly suspect that the A/D converter
on the ECU also never sees the boost climb up past 1.3, hence HAS NO WAY
( or reason to ) to make any adjustments for the increased pressure. It also
will not cut off the fuel at 1.5 bar, or force the wastegate to open if the
boost goes too high.

I'm really putting wild guesses in here, so don't take any of this as
gosple truth...

Alan Cordeiro