How to Remove Coolant Flow to the Throttle Body
By Carlos Iglesias
Rob Robinette Adds: This mod will remove the hot engine coolant flowing
around the throttle body. The coolant is there to keep ice from forming around
the throttle butterflies but unless you live in Canada you probably don't need
it. With this mod the engine will start fine, but it will idle a little lumpy
until the engine warms up. I've never had my car stall even when starting it at
temperatures below freezing. This mod will also simplify the coolant system
1. Remove the coolant hose attached to the firewall side of the throttle body
2. Remove the coolant hose which connects the bottom TB coolant outlet to the coolant
hard-pipe between the oil filter and the oil filler spout.
The coolant pipe now bypasses the throttle body
3. The hose which was attached to the top firewall coolant inlet on the TB should now be
reattached at the hard-pipe, completing the rerouting.
Safety wiring the throttle body's fast idle cam half open
4. Safety wire the Fast Idle Cam open about halfway. If you open it too much
it will interfere with the throttle's ability to fully open. Hold the Fast Idle
Cam about halfway and open the throttle and you'll see what will interfere and
where to wire the cam. The cam is located on the firewall side of the
Note: Failure to wire the
Fast Idle Cam open will not allow idle to fall to its normal speed, since the idle cam is
actuated by the thermowax rod, which is immersed in the TB coolant stream (it
will always think it's cold).
[Jay did this instead of using safety wire: I took the adjustment screw out
and took off the spring. Then I reinstalled the screw without the spring and
tightened it all the way down. That props it up at angle that seems like it will
work. I only did this because I had no safety wire and this just seemed to make
1. Regardless of climatic conditions, sufficient idle warm-up to achieve proper engine
operating temperatures before cracking the TB will also provide sufficient heating of the
TB to assure thawing.
2. Post-idle air inlet and engine bay ambient temperatures will maintain TB temperatures
3. Air inlet temperature is only "MARGINALLY" reduced (at best) by this mod.
Flyin, Racin, and Buildin Rotary Beasts,
Carlos "Spic Racer" Iglesias