I have an 89 FC ITS race car. The 5-6 ports have been bypassed and an RB header w/o O2 sensor. As far as I know the computer is stock but I do not get a check engine light when I turn the key on.
After I start the car and it starts to warm up the idle will alternate between a low and high idle. About 2 seconds for each. If I depress the clutch pedal the idle will stabilize at 2,200 RPM. The clutch lock out switch is still working.
The question I have is this. Why does the idle change? Can I disconnect/bypass the switch without any problems?

 

mostly the reason its changing is because your clutch is adding the load of the transmission and clutch together, its basically like turning your lights on. have you tried to adjust your idle yet by the fsm?

 

Since I am new to these cars, I do not know what FSM is or where.
Any help is appreciated.

Cbuzz

 

on the 2nd gen page look at the top 3 or 4 posts called "sticky" read those all the way through, they tell you where the fsm(factory service manual) is along with other helpfull links

 

Sounds like a throughout baring

 

adjust your damn tps

 

I found two switches on the clutch pedal. One is the starter lock out and the other is the cruise control disengage. When I unplug the disengage and jump it with a wire the idle stabilizes. I did this multiple times to verify the action.
For some reason it is changing the mixture or timing.
I could not find any direct correlation in the FSM.
Hopefully I can get the car on the dyno next week to see if there is any differences with the bypass or not.

 

your idle bounces up and down if its just sitting there when you start it, right?
that means adjust your tps

 

Take a look at the fsm. Look at the section called CONTROL SYSTEM, page F1-76. If you look at the *0*'s you'll see that switch affects the fuel amount/fuel pump resistor relay/ fpr/bac/ignition timing/and more. See what you think after looking at the 89FSM and those pages above.