I have a problem with coolant flow through my BACV. I did figure out where the problem is. There is hose which goes from BACV to Dynamic chamber. And a place it hooks to ( which is cooper adapter) is clogged so there is no coolant flow through my BACV which make the car idle high for quite some time ( it goes down eventually) and also I think my idle is set incorrectly because of that. I did unhook the hose and try to clean it out but it bends twice and I was not able to get past the first bend. It is clogged looks like with rust and explanation to that is that the guy I bought it from told me that the car was standing for few years and I assume cooling system got rust in it and that rust clogged the adapter. Any suggestion on how to clean it out without taking the Dynamic chamber off? Also if will not be able to clean it out with out taking the chamber off what should I look out for when I will take the chamber off.

 

well guys where is you answers? are you only good for giving suggestion on the size of turbo?

 

Is it just the hose thats clogged? Go to a local car parts store and get some coolant hose.

 

the 86-88's may be different but the coolant hose going to the BAC valve is just attached to the valve not actually going through or affecting it in any direct way.

car should idle high for a little bit on startup.

 

Oh and dude, sometimes you have to wait more than 2 hours for a reply.01-19-03 07:18 AM
01-19-03 09:18 AM

 

JPG;

 

Your on the right track, just a little off base. Like they said, the bac is not the problem. The water passes thru a fitting on the bac, but that's just to keep the bac from icing up during cold spells. Transfers heat to the bac. The bac works at apporx 120 hz and a iced up bac does no good.

Anyway, the water flows from the bac to the throttle body. It goes to the water thermowax, to heat it up, and then to a outlet at the bottom of the thermowax to return to the *block*.

So what has happened, is the thermowax is clogged up. Remove the thermowax and clean it out so the water can flow. Then the thermowax will work and the idle will drop down a lot sooner after starting.

Its the piston on the thermowax that keeps the throttle plates cracked open to give you the high idle (after the initial 3000rpm startup for 17seconds that is the function of the bac and the Air Bypass Solenoid).

Once the thermowax's piston expands, it drives the cam off the roll pin in the picture in the above post. That lets the primary throttle plate return to its preset position.

 

Would a bad BAC give you terribly bad gas mileage on a stock car?

EDIT: as in 13mpg on the highway on a T2 (s4)

Fresh rebuild.

 

***Would a bad BAC give you terribly bad gas mileage on a stock car? ***


No.

 

your low gas milage is probably due to the rebuild not being fully broken in yet (if its that fresh of a build). should get better as it starts to seal up better. did you get new filters and O2 sensor during the rebuild?