[Diy_efi] Audi EFI conversion?

[Torbjörn Forsman]

5-cylinder Audi have a somewhat more sophisticated system. The full 
throttle enrichment is not done by the taper of the air metering cone, 
but by a vacuum sensitive element in the warm-up regulator.

Furthermore, i think that a '86 that is sold in the US should have 
lambda control, if it doesn't have KE-jetronic then the lambda control 
is made by a pulsed valve (similar to the injectors of an electronic 
system) which is connected between the control pressure and the lower 
chamber of the fuel metering unit. A very simple ECU runs that valve at 
a fixed duty cycle when the engine is in open loop and changes the duty 
cycle for lambda control when in closed loop. This system is sometime 
referred to as K-lambda.

Here in Sweden, it is now a big interest for converting older cars for 
running on alcohol fuels (E85), as those are much cheaper than gas. 
(95-octane gas costs about US$ 5.40 per gallon while E85 costs US$ 
3.45-3.80 per gallon).

On K-jet systems, the fuel flow can be increased by either installing a 
suitable counterweight at the fuel metering arm (only possible where it 
is enough room at the fuel meter end of that arm) or by lowering the 
control pressure. The simplest way of doing that is by installing shims 
between the body and the base of the warm-up regulator. However, that 
method is no good on the vacuum controlled regulators of 5-cylinder Audi 
and turbo engines.

/Torbj?rn Forsman

Tomas J. Sokorai Sch. wrote:
> On Friday 04 November 2005 15:26, Torbj?rn Forsman wrote:
> 
>>I think it would be wasted work to replace the K (or KE) system with an
>>all-electronic one. It is much more fun to learn tweaking the K-jetronic
>>system for one's own needs!
> 
> 
> If it is only a K-jet, I would like to see what tweaks besides the two mixture 
> screws could be done, as the fueling curve itself is determined by the 
> physical tapers of the body around the metering plate.....
>