Dougs951S

I need some wisdom on what to do with the little 2 pronged vacuum thermovalve under the intake, this guy right here


I've deleted the charcoal canister and the two associate valves and I obviously had to reroute my vacuum lines. As far as I see it, one of those ports has vacuum signal at all times (the one closer to the front of the car), while one only has vacuum once the engine has come up to temp. I basically just used a T fitting and bridged both the ports together (rather than trying to block one off) and then ran the line to under the throttle body like normal. Is this ok to do, or is there a way to delete this now unused fitting? The way I have it now, the little fitting under the throttle body that bypasses the throttle blade when its closed has constant vacuum at all times, the way its supposed to. So can I leave everything the way I have it?

Dougs951S

My vacuum lines basically look like this






Basically my question is, is it ok to leave the two ports bridged like that, or should the rear one that normally is attached the the fuel vapor control valve be capped somehow? I dont think it makes any difference, but I also dont know if the control valve allows vacuum to be placed on the rear more of the two ports during normal operation on a stock car, since that is exactly what I am doing now.

Dougs951S

I just had a "derp" moment and realized the entire purpose of that fitting beneath the throttle body is to feed in fuel vapor when the control valve allows it (engine hot and throttle open). So, its not needed. Should I remove/cap off both ports on the thermo valve and then also cap off the fitting on the throttle?

Will Feather

I'd be interested in the answer as well, I would like to delete all fuel vapor/canister vacuum lines as well.

Teddy952

I didn't connect anything to that valve and blocked off the port under the throttle body when I removed my EVAP system.

V2Rocket

just put a vac cap onto the tb port.
then just find a grub screw that matches the thread of the bunny-ears...or just leave the bunny ears on there un-hosed.

Will Feather

Teddy952, got a vacuum diagram of your car?

Teddy952

Not at the moment. I'll sketch one out when I get back to my garage.

ekoz

+1 did the same thing, put a cap on throttle body and left bunny ears unplugged. Its essentially a temperature switch to start pulling vacuum so leaving it there unplugged does not hurt anything.

Dougs951S

I dont understand how leaving the bunny ears unplugged does not constitute a vacuum leak, one ear has constant vacuum amd if it isnt sealed or routed back into the intake, you ARE leaking vac/boost.

Spidey944

The bunny ears pull vacuum from one side, to the other once temp is reached. if no vacuum is applied to one side, then no vacuum is being sucked through the other side.

Dougs951S

I dont think this is true...unless I'm crazy, I stuck a vacuum line over both bunny ears one at a time to test which had vac signal. The rear port that normally attaches to the vapor control valve has no vacuum obviously unless the engine is hot, but the forward ear that normally goes to the throttle body does indeed pull vacuum as soon as the engine starts. I put my finger over the vacuum line I attached to it and it was definitely pulling vacuum...

I did both of these tests with the other bunny ear not being test uncovered and open to ear.

Spidey944

The line coming off of the throttle body would be the vacuum source. When the switch is closed the vacuum just dead-heads at the switch. When the temp reached specified temp, then the valve opens up to allow vacuum to suck through the other side.

Dougs951S

When I tested it, the lined was not hooked to the throttle body, just to the bunny ear and then the other end of the line was to my hand, where i observed a vacuum signal. I will repeat this test to make sure I'm not nuts.

Edit: It does make sense though, the thermovalve sits on a water line where it gets the temp signal. There really is no way for either bunny ear to have a vacuum source if not hooked to anything.

mahoney944

Just cap the throttle body nipple and leave the thermo valve un hosed on both sides. Cap any vac lines that are applicable. You basically have a vac loop from the fuel return and damper, then cut that hose and install a T to connect to the manifold between cylinder 3 and 4 then T in the bypass valve and T in the blue and black one way valve. That goes to the firewall. The klr line doesn't change and you'll be plugging the j boot in 2 spots with a bolt and hose clamp. Remove all the charcoal canister stuff the whole way back to the gas tank. Then install a filter at the tank to let it vent but not to suck in contaminents.