Re: Throttle switch update [1]

[a6561TB@gnn.com (Igor Kessel)]

>Maybe if somebody could explain how the switch works.. It would make my
> life
>easier. I assume that the switch provides resistance which returns the car
> to
>normal idle upon throttle release... right? Therefore.. lubing the thing..
> just
>made it worse because the switch wasn't providing much resistance before
> right?

Hi, Osman, sorry for all this tech lingo. I will try to make the previous 
post user frendlier:

I took mine apart a year ago. It has 2 on-off micro switches inside. Here is 
what you do:

Unplug the switch.
1a. Set your multimeter to OHM position. Set the range to the most sensitive
one (RANGE = x1ohm full scale is best). You will be checking CONTINUITY, 
that is why you can't use a voltmeter.
 
1. Connect one lead of your OHM meter to the central terminal of the switch,
the second lead - to the top terminal of the switch, polarity is irrelevant.
You will be reading the resistance R between two terminals. 
When switch is @ idle position, R should be=0 . 
Open the throttle approx. 5°, R should change to infinity.

2. Now connect ohm meter to the central terminal and the bottom terminal of 
the switch.
When switch is @ idle position, R should be=infinity . 
Open the throttle approx. to the max, imitating full throttle acceleration. 
R should change to 0.

If the switch is adjusted properly (i.e. clicks @ idle and full throttle 
positions) and either of tests is a no-go, then the switch might be 
faulty.Don't get fooled by the fact that it clicks. It does not mean that 
there is the electrical connection!

Split it apart, WASH it in CH2COOH , methanol or brake cleaner to get read 
of  of that WD40 stuff and GENTLTY polish the contact group with a fine grit
sand paper. Blow all the grit dust off from in between the contacts, or they
will arc weld themselves into the surface later. Make sure the tests 1 & 2 
are OK now. If yes, hermetically silicon rubber the clam shells together, 
let it set under pressure overnight and you are done. 
Readjust the switch on the car ELECTRICALLY (see 1&2) on the car, not just 
click-test it.

It is imperative that at least the full throttle portion of the switch 
works. On our cars under the full boost this switch, when closed by your 
foot, basically tells the ECU to screw the maps and to kick in the max fuel 
enrichment to maintain the optimal air/fuel ratio. If the switch fails to 
close the circuit, you will enter the fuel starvation mode under full boost, 
which leads to detonation (dont expect to hear it - it will be muffled by 
the whining turbo/exhaust). Fuel starvation is the second quickest way to 
kill the engine, known to me, bested only by the oil starvation.

Sorry for occupied Kbytes, I've done the best I could.
E-mail me if some ?? still remain. 
Good luck.  



Igor Kessel,
'89 200TQ, chipped and MOMO'ed through out,
in Tornado "arrest-me-officer" Red;
'88 Fox, "the FOX-machine";
ex '85 5000s, "the EE's nightmare"
Phila PA, USA
a6561TB@gnn.com