Re: 16v fuel enrichment module (paging Brian Hannold)

[Brett P VanSprewenburg <brettv@rocketmail.com>]

---Pei-Chung Ting <chungsteroonie@yahoo.com> wrote:

> I heard that Mr. Brian Hannold from this fine list has in the past made
> fuel enrichment modules for 16v sciroccos.  Can you get in touch with
> me to explain how your setup works and compares with other ridiculously
> over-priced TT and autotech products on the market?  I'd appreciate any
> advise on this matter.
> 
> Thanks for your time,
> 'Chung

Once more into the breech...

Anyway, there are pluses and minues to both boxes.  Autotechs box supposedly
works with vacuum, rpm's, and full throttle while the TT box only works
under FT.  Autotech also directly modifies the DPR current, while the TT
box works a bit more within the system and only tries to fool the computer
into thinking that the engine is 'cold' and requires more fuel.  Both
approaches can work, but practically, things sometimes work a bit differently.

The TT box is very very simple to make yourself.  Here's how it works:

The coolent temperature sensor (CTS) on the side of the cylinder head works
like a resister that varies it's value with temperature.  As the car warms
up it changes, the computer reacts to this input (as well as others) by
changing the current sent to the dynamic pressure regulator (DPR) on the 
back side of the CIS-E fuel distributor.  The TT box works by substituting
a different resistance value (one indicating a cool engine) for the CTS
when the full throttle enrichment (FTE) swtich, on top of the throttlebody,
is activated by the gas pedal.  The TT box does this by tapping the 'cold'
side of the FTE switch (N/C) so that when the switch closes, 12v flowing
through the swtich also activates the relay.  The relay is also plugged
into the CTS, and the harness that the CTS is normally plugged into. Normal
operation passes the CTS 'signal' to the TT box, through the relay, then
back down to it's normal harness connector.  When the FTE is activated,
the relay closes, and a set resistance value (around 1.9-2.2k ohms) takes
the place of what-ever value the CTS was 'sending'.   This indicates a cold
engine, the computer increases the DPR current, and less fuel gets sent
down the return line, which means more fuel gets sent to the injectors.
Everyone is happy. 

Unfortuneately, FTE can happen at any rpm and the engine doesn't always
'need' that extra fuel, and over-enrichment at low rpms most definitely
causes engine bogging.  Which is why I made a box that senses rpms and
varies the CTS resistance. :)

Is this FAQ material yet?

==Brett


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