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My engine vibrates A LOT at idle, and I noticed today if I were able to raise the idle just a little, the vibration subsides considerably. I don't see how it's possible, with the throttle setup, am I missing something? How do I raise the idle?

Drill a hole in the throttle plate is the best way to do it.

Really? I suppose that would work, wouldn't it? I'll give that a try, see where it gets me. Thanks for the idea!

Thanks! That worked great.

No prob

^^ you serious

My 05 TB has an adjustment screw much like the ones on the Lorenzo and MPx TB's. I'd try that first.

Actually... according to a very informative lecture I sat through two weeks ago given by Ed Peters a DCx engineer that worked on the Neon project... that screw is only there to adjust the throttle plate enough that it doesn't stick shut when it closes. That's all it's ment to be there for. Adjusting it for idle throws the computer off since when you adjust that screw it gives the computer a mixed signal between the TPS, IAC and MAP sensor when it compares what at each are at to know how much fuel to give the the engine at idle. He highly recommended using about an 1/8" drill bit to drill a hole through the throttle plate instead to keep everything in line.

And I have to go with Diablo on this one. I drilled one hole, but it wasn't enough, so I drilled another. It put the idle into a very acceptable range, and I'm quite happy with it!

Where did you drill it at? Pics? Probably a beast to take pics of it, but hey! Never hurts to ask, I for one, take pics of almost everything I do/did. I then hang them on the fridge with my gold star and...

I believe BRR has done this as well for an old problem he had. He has a picture of it somewhere.

maybe someone could do a howto with pics on this one, cause it sounds interesting, but i'd be very nervous to drill in the wrong spot.

w3rd - but if I find out the spot, I will do a how to... couldn't take me to long

I didn't take pics, it was about a 5 minute job, even with having to take it back apart to drill the second hole.

I have an ebay instake, so it was just two hose clamps and the TB was free enough to twist around and get the drill inside. I installed the drill bit as far out of the drill as I could, so it would reach all the way to the butterfly (throttle plate). Make sure you disconnect the TB-to-intake hose and get it out of the way so no shavings get inside the intake. It looks like the plate is plasic anyway, but better safe than sorry.

If you look inside the TB, you'll see the plate, split across the middle by the pivot rod/bar. I drilled the holes into the bottom half, so it wouldn't try to open as I pressed with the drill.

It's really quite simple, as long as your drill will fit inside, you shouldn't have any issues. As far as size is concerned, I think that would depend on how far you want to raise the RPM, start small and go from there. Where location of the hole is concerned, I doubt it matters, as long as air can get through.

I agree ^.

Seriously, you guys. The only wrong way to do this is to drill the hole in the intake manifold. Just drill it somewhere in the TB butterfly plate.

Diablo, you must be mistaken, I dont recall ever doing this?
I have adjusted idle with the scre without any problems, but I never took a chance of drilling the TB plate....

BlueMonster wrote:Thanks! That worked great.

did u clean the metal shavings out of the tb?

Diablo0 wrote:Actually... according to a very informative lecture I sat through two weeks ago given by Ed Peters a DCx engineer that worked on the Neon project... that screw is only there to adjust the throttle plate enough that it doesn't stick shut when it closes. That's all it's ment to be there for. Adjusting it for idle throws the computer off since when you adjust that screw it gives the computer a mixed signal between the TPS, IAC and MAP sensor when it compares what at each are at to know how much fuel to give the the engine at idle. He highly recommended using about an 1/8" drill bit to drill a hole through the throttle plate instead to keep everything in line.

interesting.. thinking about trying this.

Yes and no. The butterfly is plastic, so o metal shavings. And yes, I did it while the TB was disconnected from the intake tube, blew it out and reconnected it.

Diablo0 wrote:Actually... according to a very informative lecture I sat through two weeks ago given by Ed Peters a DCx engineer that worked on the Neon project... that screw is only there to adjust the throttle plate enough that it doesn't stick shut when it closes. That's all it's ment to be there for. Adjusting it for idle throws the computer off since when you adjust that screw it gives the computer a mixed signal between the TPS, IAC and MAP sensor when it compares what at each are at to know how much fuel to give the the engine at idle. He highly recommended using about an 1/8" drill bit to drill a hole through the throttle plate instead to keep everything in line.

i think you should become the offical neon tech on this board

My wife drives the car, and I'd also like to report that she is loving it, and even mentioned it felt a little stronger off the line. Bonus! I don't know if that is accurate, but it makes sense, I guess.

I'm far from a tech... I just regurgitate what I hear to the best of my abilities I usually comprehend it also to the best of my abilities

And Chris (BRR)... I could have sworn it was you Hmmm... maybe it was Louie a long time ago I know someone with a Red R/T did it.

DIABLO:
Are you talking about forcing the computer to relearn an idle or drilling the TB for an idle?

He is talking about drilling a hole in the butterfly to simulate the butterfly being slightly open and raising the idle.

I'm talking drilling a hole to allow more air to pass, air that wouldn't be controlled by the IAC motor. The hole isn't that large, only 1/8" or so, just enough to raise the RPMs a couple hundreds and not an extra thousands. Granted if you drill too many holes or too big you will create a problem where the computer is unable to reach its idle speed and throw a code. By only drilling a small hole it won't cause that as there isn't enough air passing through it to cause it to raise it that much.

i did it and my idle is better and when you let go of the gas it cruises and it stays there. pretty amazed what a small hole can do.

I just drilled an 1/8th inch hole into my TB Butterfly. Idle is right at 850rpms and the car is more responsive when you get back onto the throttle. Cant wait to do some 0-60 runs. Right now I have no backseat, and nothing in the trunk (carpet, spare, jack, etc) due to the water issue. I should beat my 6.88 best time. OR i could have really bad traction issues, like usual. lol

What should rpms be at idle? Mine is about 500. That too low??

waaay to low.. they should be around 750 - 900

Silver2gn4me wrote:What should rpms be at idle? Mine is about 500. That too low??

That's not too low for an ATX.
MTX cars typically idle at 800 and above.

MIne is a MTX. I think I will do the 1/8 hole thing and see what happens.