Ok, i finished the TB mod, and put everythin back together... But the car wont idle.. i have to give it gas to keep it on. it runs smooth as long as my foot is on the pedal, but once i take it off, the RPM's drop and the car just dies.. Could i have forgotten to do something? or do i need to adjust something. would this have anything to do with the throttle cables?

 

have you warmed the car up yet?

 

thx for the replay santiago, Anyways, i fixed the idle, the cable was unscrewed that held the idle, im a dumbass.. Anyways. a new "problem" After i shut the car off, i hear a really faint "pfffffffffffffff" near the intake manifold and I dont know where its coming from. It only does this when the key is in the "on" position with the car off. Any ideas what this could be?

 

you need to adjust the tps, if that doesnt work then you need to find the throttle stop screws on the bottom of the tb to set the idle. its a real pain in the *** and takes awhile. this is the reason i refuse to ever do a tb mod again. i find the gains were minimal and made the car a pain in the *** to drive. but to each his own, if you get it working good then more power to ya.

 

whyd it make the car a pita to drive?

 

it wouldnt idle cold at all, kinda sucks when you have lots of stoplights to go through early in the morning. when it warmed up it was ok but the idle never felt right,the car ran pretty good on the highway but i dont spend that much time on the open road, city driving was not as easy. i did everything right, im no noob behind the wrench but i really didnt like it and found the gains were not worth losing cold idle. obviously many on the forum like the tb mod and find it worthwhile but i did not. luckily my tb was destroyed in my pd failure fire so i wont have to worry about it again. also i dont think i could of passed emissions with the mod.

 

pain in the *** to drive? Hmmm, I've never had a problem really since I did the TB mod. When I did the TB mod I also ported my upper and lower intake manifolds, and after putting everything back together of course I had to adjust the idle speed screw and secondary throttle stop screw, I was expecting that. But after some tinkering and monitoring for a couple days it was all good and I never had to fool with it again. My idle is strong, constant, and my driveability is still fine, no big deal. But like you said, to each his own

 

shoot...nobody ever said anything about the idle problems.

I just recently did the TB mod and have that same cold engine crap going on...

If the guides to the TB mod don't even mention cold idle problems, don't u think there's something we're doing wrong?

I already adjusted TPS, and idle valve at the top of the TB. Could there be anything else we're forgetting? I don't see how just removing a set of butterfly valves could kill the engine like that.

Did u guys port your TB too?

-grant

 

Oh yah, and about the cold idle problems. Never had a single problem with idle when it's cold out, when the engine is cold, or when the engine is cold AND it's cold out. Once again all i had to do was tweak the idle initially and never had a problem again.

 

well the reason people have idle problems removing the butterflys is because when you crank your car cold they restrict air flow causing the car to run slightly richer than normal which helps with warming the car up... in many TB threads there have been numerous replies about your idle during cold... i have no problem with mine starting up but i also have my start up procedure working so that really helps... but like i said thats why the car is so hard to keep idling cold when you remove the butterflys... its a small part but a major part in running the engine cold... anyhow i love my TB mod and driveability is just the same for me and i ported the crap out of mine

christopher

 

Completely wrong sorry. You are mixing up the two different and very separate systems on the TB, the thermowax and the double-throttle system.

On the rear of the TB is the thermowax, which has coolant flowing through it. When the engine is cold this opens the primary throttle slightly to increase idle speed so the engine doesn't stall. As the engine warms up the thermowax rod extends and the primary throttle is closed to return the idle speed to normal. This does not affect mixtures at all. Mixture control is done by the ECU, not the TB.

The double-throttle system comprises the #2 secondary throttles (the second upstream pair), a vacuum actuator/damper and the thermovalve. The thermovalve is attached to the thermowax and shares its coolant flow. On NA engines this serves only one purpose. When the engine's cold the vacuum actuator closes the #2 secondary throttles so the engine's output is limited. When the engine warms up the thermovalve releases the vacuum in the actuator and the throttles fully open.

On Turbo engines the system works as above, but there's an additional function. The #2 secondary throttles are actuated by the #1 secondary throttles, but their opening rate is slowed by the damper. This is to stop a stumble from the secondary ports suddenly flowing air. Removal of this system improves throttle response because the secondary throttles are now effectively open sooner. Since NA don't have this system, there's no gain in throttle response from removing the #2 secondary throttles.

The two systems (the thermowax and the double-throttle system) are totally separate and don't affect each other. That means you can remove the double-throttle system for an improvement in throttle response on Turbos, while keeping the thermowax and a decent cold idle.

Most people follow RETed's TB mod how-to, and incorrectly assume that the entire procedure must be followed for it to work. NA owners also incorrectly assume that they will see the same benefits as Turbo owners. A pair of open throttles in the airstream present only a minor impediment to airflow, so the power gains from the TB mod are tiny. Only Turbos will see an improvement in throttle response. The TB mod is practically pointless on NA engines.

 

My car has the TB mod and some porting. I use left foot braking while the engine is warming up to keep the engine from dying. It has become very easy. It has helped me become good at left foot braking by making me practice in order to keep the engine running when stopping.

There's an upside to every downside, and discipline makes it happen. Ha ha ha!