yesterday i did the tb mod on my 87 t2
i follow the write-up on fc3spro.com
when i start the car my idle spike between 1000-1600 rpm
so i take off the thermowax off and re-route the 90° coolant hose on the rear housing to the BAC valve
i think that my idle problem was not the BAC valve because it connected to coolant

do i need a tps adjustement maybe??

any help will be aprreciated !

 

Uh, you took that thermowax after doing the TB mod?


-Ted

 

no , i remove the thermowax and the fast idle cam , after i remove the shaft with the 2 butterflies , i seal the 2 shaft hole and when i start the car after the idle spike

what do you think?

 

your rear butterflys are not shut enough maybe, mine needed to be closed up a bit otherwise the idle was at 2500.

 

yes maybe!
it's possible that the secondary did the restriction before i remove it
i will check

 

you dont need coolant through BAC for it to work correctly do you?

 

No.

Yeah, you might've dislodged crud that is propping the throttle plates open.
It's a good idea to shoot the bores with a couple cans of brake or carb cleaner just to get all the crap out.

Also, use the throttle stop (on the primary) to adjust idle RPM's.


-Ted