# WOT switch question - CIS-Lambda



## Holden McNeil (Jul 26, 2004)

I currently own an 83 Rabbit LS (1.7L) while a buddy owns an 83 GTI (1.8L) both of which are running the factory CIS-Lambda.... His car has a WOT switch but mine does not... I understand how the WOT swtich works but I'm wondering why there is this difference and should I wire one into my setup?
Thanks in advance http://****************.com/smile/emthup.gif


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## Jettaboy1884 (Jan 20, 2004)

*Re: WOT switch question - CIS-Lambda (Holden McNeil)*

Hey there buddy, my car is a 2.0L !
(That is, of course, assuming you are reffering to me)


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## Holden McNeil (Jul 26, 2004)

*Re: WOT switch question - CIS-Lambda (Jettaboy1884)*


_Quote, originally posted by *Jettaboy1884* »_Hey there buddy, my car is a 2.0L !
(That is, of course, assuming you are reffering to me)









I am (and so is mine) but I'm talking about stock... few people would understand the full ABA swap on CIS


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## Jettaboy1884 (Jan 20, 2004)

*Re: WOT switch question - CIS-Lambda (Holden McNeil)*

I figured as much. I was just trying to be a nuisance.








I would like to know this as well. So when comparing an '83 1.7L Rabbit and an '83 1.8L Rabbit, why does the 1.7 have no WOT switch?


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## WackyWabbitRacer (Apr 24, 2001)

*Re: WOT switch question - CIS-Lambda (Holden McNeil)*

According to the ETKA, the same Oxygen Sensor Control Unit (P/N 035-906-263F) is used on both the 1.7L and 1.8L engines. 
The WOT switch P/N is 067-906-028 that is used on the 1.8L throttle body.
However if you look at the wiring diagrams for the Oxygen Sensor System, the "pin connections" on the Oxygen Sensor Control Unit are different between the 1983 1.7L and the 1983 1.8L GTI.
I have no verification but it appears the same control unit used for both engines but different pin connections were used for the WOT switch function.
Conseqently it appears that a WOT switch could be added to a 1.7L throttle body if the appropriate wiring harness was used so the pin connections on the Oxygen Sensor Control Unit reflected those for a 1983 1.8L GTI configuration.
Cheers, WWR.


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## Deathdub (Jan 8, 2004)

*Re: WOT switch question - CIS-Lambda (WackyWabbitRacer)*

The OXS control unit diagrams are conveniently side by side in the Bentley manual. It looks like the only significant changes in the wiring are that the full throttle switch has one side connected to ground and the other side to the same pin as the coolant temp switch (pin 7, and 12 through a jumper which is already there on the 1.7 as well) effectively shorting the temp sensor to ground. The other difference is on the 1.7 there is a jumper between pins 26 and 31. This changes to pins 26 band 33. I don't know if that jumper has any effect on the full throttle function but its not that hard to change. I imagine the 2.0 could use the enrichment even more than the 1.8 so hit up a Junk yard and get some cheap speed. http://****************.com/smile/emthup.gif


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## rorin8v (Oct 15, 2007)

would it matter which side is connected to the ground.
also would it matter if i crossed the wire to my coolent temp?


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## Southcross (Jul 2, 2004)

*Re: WOT switch question - CIS-Lambda (WackyWabbitRacer)*


_Quote, originally posted by *WackyWabbitRacer* »_According to the ETKA, the same Oxygen Sensor Control Unit (P/N 035-906-263F) is used on both the 1.7L and 1.8L engines. 
The WOT switch P/N is 067-906-028 that is used on the 1.8L throttle body.
However if you look at the wiring diagrams for the Oxygen Sensor System, the "pin connections" on the Oxygen Sensor Control Unit are different between the 1983 1.7L and the 1983 1.8L GTI.
I have no verification but it appears the same control unit used for both engines but different pin connections were used for the WOT switch function.
Conseqently it appears that a WOT switch could be added to a 1.7L throttle body if the appropriate wiring harness was used so the pin connections on the Oxygen Sensor Control Unit reflected those for a 1983 1.8L GTI configuration.
Cheers, WWR.

Essentially, when the WOT swith is activated it takes the ECU into "open loop mode" (or is closed loop, I always get that backwards, essentially it ignores the O2 sensor feedback) and makes the Frequency Valve operate at 80% instead of the normal 50%. This richens up the mixture at WOT, essentially gives you about a 2-3HP kick in the pants at high RPMs. 
I have done this mod to my 1.7l... combined with an Audi Throttlebody, makes for a nice top end (well, considering its a 1.7l







)


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## rorin8v (Oct 15, 2007)

so you basicly hooked the switch up to kill your o2 sensor while your in higher rpms?


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## Southcross (Jul 2, 2004)

*Re: (rorin8v)*


_Quote, originally posted by *rorin8v* »_so you basicly hooked the switch up to kill your o2 sensor while your in higher rpms?
sorry... I didn't specify, I swapped an entire '84 GTI harness & ECU into my '81. I was just giving information on what the switch does.
Theoretically if you were to "short" the two leads to the coolant temp switch (located on the right side of the head, in a coolant fitting between two hoses. Switch is "on" when cold and "off" when hot.) you "turn off" the ECU and it will stop reading the O2 sensor... but will only run the FV at about 50%. The Later ECU has a built in circuit to "boost" the FV operation to 80%


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## rorin8v (Oct 15, 2007)

i was dinking around with my 85 and i unpluged my coolent temp sensor and it wanted to kill itself


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## Southcross (Jul 2, 2004)

oh... if your really crafty with electronics, you could rig up a circuit that would "fool" the ecu into thinking your running lean. plug your O2 into it, then the "dohicky" into your ECU input. make a "on/off" trigger that ran to a WOT switch, so when you go WOT there was pull-up circuitry to raise the voltage above the stoich level to make the ECU think its lean and increase the FV operation.... incorporate some adjustable resistors and you can adjust how much pull-up voltage (you only need about .05 to .1 to make the ECU think its lean).... all ideas I wish I knew how to do


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## WackyWabbitRacer (Apr 24, 2001)

*Re: WOT switch question - CIS-Lambda (Southcross)*


_Quote, originally posted by *Southcross* »_
Essentially, when the WOT swith is activated it takes the ECU into "open loop mode" (or is closed loop, I always get that backwards)

The activation of the WOT switch on the throttle body puts the ECU into an open loop status so the ECU disregards the O2 sensor input.
Cheers, WWR.


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## Southcross (Jul 2, 2004)

*Re: (rorin8v)*


_Quote, originally posted by *rorin8v* »_i was dinking around with my 85 and i unpluged my coolent temp sensor and it wanted to kill itself
operation of CIS on a Mk2 is slightly different. On a Mk1 the coolant temp switch is On/Off, on the Mk2 its variable resistance.... higher temp the higher the resistance (IIRC), by unplugging it the ECU freaks out since it has no signal.


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## rorin8v (Oct 15, 2007)

well i was reading the bently and found out which wires go to what, at the harness connector for the ecu. and discovered there was never a female connector at #5 terminal. so i went my was down the volkswagen and picked a couple up for almost 10 bucks. well i installed it and had to tap into the #2 terminal from what i was getting at from the book. i havent connected it to a plug yet, because im not too sure if it matters about which side its connected to on the wot switch.


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