Ported throttle body plate sealant
Aug 8, 2009, 03:28 AM
#31
The biss is closed all the way, and the car still idles at 2k rpm. The weird thing to me is the car idled at 1k rpm before switching out the injectors and getting it tuned. I think the gap on the butterfly is too big, but I also think there must be another issue because the idle is so high. This is driving me crazy, and I gotta figure something out in the next couple days.
Another thing, the black film you describe on the plate may just be built crud and it's OK to have say, 0.2mm difference ID TB - OD plate. Nevertheless, if it is in fact leaking too much through the TB and it is not related to a vacuum leak elsewhere your only options will be:
1) a new machined plate
2) lean idle afr to lower rpm (mine is about 20 AFR at idle)
3) flash idle stability to the ecu and lower the timing
4) remove the IAC system altogether and block the ports controlling idle by the biss and/or other methods above. This will make cold starts and AC operation troublesome though
Last edited by C6C6CH3vo; Aug 8, 2009 at 03:30 AM.
Aug 8, 2009, 08:44 AM
#33
What is your AFR at idle? If it's rich because the fuel trim is pegged, there will be more power at idle and the rpm will be too high.
Another thing, the black film you describe on the plate may just be built crud and it's OK to have say, 0.2mm difference ID TB - OD plate. Nevertheless, if it is in fact leaking too much through the TB and it is not related to a vacuum leak elsewhere your only options will be:
1) a new machined plate
2) lean idle afr to lower rpm (mine is about 20 AFR at idle)
3) flash idle stability to the ecu and lower the timing
4) remove the IAC system altogether and block the ports controlling idle by the biss and/or other methods above. This will make cold starts and AC operation troublesome though
Another thing, the black film you describe on the plate may just be built crud and it's OK to have say, 0.2mm difference ID TB - OD plate. Nevertheless, if it is in fact leaking too much through the TB and it is not related to a vacuum leak elsewhere your only options will be:
1) a new machined plate
2) lean idle afr to lower rpm (mine is about 20 AFR at idle)
3) flash idle stability to the ecu and lower the timing
4) remove the IAC system altogether and block the ports controlling idle by the biss and/or other methods above. This will make cold starts and AC operation troublesome though
Aug 8, 2009, 04:40 PM
#34
Check the pvc line on the boost side. Then check the two hoses going from the egr valve up to the TB and also to the two going to the egr solenoid through the tee.
Got to be a leak behind butterfly somewhere, even through injector seal. You can spray alcohol or water over areas you think might leak. Car will stumble when liquid gets sucke through the leak
Got to be a leak behind butterfly somewhere, even through injector seal. You can spray alcohol or water over areas you think might leak. Car will stumble when liquid gets sucke through the leak
Last edited by C6C6CH3vo; Aug 8, 2009 at 04:45 PM.
Aug 8, 2009, 04:47 PM
#35
Check the pvc line on the boost side. Then check the two hoses going from the egr valve up to the TB and also to the two going to the egr solenoid through the tee.
Got to be a leak behind butterfly somewhere, even through injector seal. You can spray alcohol or water over areas you think might leak. Car will stumble when liquid gets sucke through the leak
Got to be a leak behind butterfly somewhere, even through injector seal. You can spray alcohol or water over areas you think might leak. Car will stumble when liquid gets sucke through the leak
Aug 8, 2009, 11:41 PM
#36
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Have you tried adjusting the throttle stop?
I would check that before messing with coatings etc inside the throttle body.
With the engine off, back off the stop screw until the plate just starts to stick slightly when cracking throttle open by hand.
Then wind the stop screw about half a turn back in and tighten the locknut.
Also check that the throttle cable has a little slack.
Although it does seem like you have a vacuum leak since it was holding idle fine before.
Spray bottle with some ether works great to find them.
I would check that before messing with coatings etc inside the throttle body.
With the engine off, back off the stop screw until the plate just starts to stick slightly when cracking throttle open by hand.
Then wind the stop screw about half a turn back in and tighten the locknut.
Also check that the throttle cable has a little slack.
Although it does seem like you have a vacuum leak since it was holding idle fine before.
Spray bottle with some ether works great to find them.
Aug 9, 2009, 12:56 AM
#37
Have you tried adjusting the throttle stop?
I would check that before messing with coatings etc inside the throttle body.
With the engine off, back off the stop screw until the plate just starts to stick slightly when cracking throttle open by hand.
Then wind the stop screw about half a turn back in and tighten the locknut.
Also check that the throttle cable has a little slack.
Although it does seem like you have a vacuum leak since it was holding idle fine before.
Spray bottle with some ether works great to find them.
I would check that before messing with coatings etc inside the throttle body.
With the engine off, back off the stop screw until the plate just starts to stick slightly when cracking throttle open by hand.
Then wind the stop screw about half a turn back in and tighten the locknut.
Also check that the throttle cable has a little slack.
Although it does seem like you have a vacuum leak since it was holding idle fine before.
Spray bottle with some ether works great to find them.
Can you elaborate on the spray bottle with ether to find vaccum leaks. I don't think I have any, but a new trick is always welcomed?
LOL
.
Aug 10, 2009, 01:05 AM
#42
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Didn't realise earlier that the Evo 8/9 throttles do not have an adjustable stop like Evo 1-6 did.
Just another thing they had to make non-adjustable for emissions reasons I guess...
Just another thing they had to make non-adjustable for emissions reasons I guess...
Sep 14, 2010, 08:00 AM
#43
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Could somone please post pics of before and after sealing of the throttle plate/ throttle bore/ throttle shaft.
Or even a pic of a brand new throttle body with the coating on it.
I cleaned all of this stuff off too and now my idle is totally screwed up.
I ordered the Molykote 321 but have no idea where to spray or not to spray.
It would be greatly appreciated.
Or even a pic of a brand new throttle body with the coating on it.
I cleaned all of this stuff off too and now my idle is totally screwed up.
I ordered the Molykote 321 but have no idea where to spray or not to spray.
It would be greatly appreciated.
Nov 28, 2010, 10:17 PM
#45
bumping this old thread... I installed my buschur 65mm TB and even after closing the biss my idle was stupid high (over 2000rpm). I thought maybe I had a loose vacuum hose or something on the intake manifold so I swapped my stock TB back on and boom idle back to normal so I knew it was something with the 65mm TB. Once I took it off and looked at the butterfly valve, I noticed there were clear areas around the edges where air would get through. I tried shining light through it next and almost around the entire valve light was getting through. Is this normal? I'm pretty sure with all this air getting through was the reason my idle was so retardedly high. I'm gona call buschur in the AM to see what they say about it.
With this sealant stuff, where exactly are you guys spraying/applying it onto?
With this sealant stuff, where exactly are you guys spraying/applying it onto?