# NEUSPEED Throttle Body Help.



## White_Rabbit_GTI (Apr 27, 2007)

I have a question just tossed on my Neuspeed big bore throttle body on my mk1 GTI tonight and right away after putting it on I started it up and the idle was about 2000RPM so I cranked down the mixture screw on the TB adn got it down to 950 +/-25, so I got in and took it around the block came back and the idle was 1500 or so then climbed back near 2k again cranked down the mixture screw back to about 950 again took it out and it had climbed back up to 2k.
Why is this happening? am I going to have to take it in to my local shop to get the cars A/F mixture professionaly readjusted?


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## wclark (Mar 28, 2001)

*Re: NEUSPEED Throttle Body Help. (White_Rabbit_GTI)*

What is a Neuspeed throttle body?


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## Longitudinal (Nov 13, 2004)

*Re: NEUSPEED Throttle Body Help. (wclark)*


_Quote, originally posted by *wclark* »_What is a Neuspeed throttle body?

It's a factory Pierberg large two-valve TB with a Neuspeed casting on top.


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## antichristonwheels (Jun 14, 2001)

*Re: NEUSPEED Throttle Body Help. (White_Rabbit_GTI)*

replace th o-ring on the screw


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## White_Rabbit_GTI (Apr 27, 2007)

*Re: NEUSPEED Throttle Body Help. (antichristonwheels)*

o-ring on the mixture screw?
Does it just unscrew out?
what size is the o-ring?



_Modified by White_Rabbit_GTI at 9:34 AM 10-27-2007_


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## White_Rabbit_GTI (Apr 27, 2007)

*Re: NEUSPEED Throttle Body Help. (White_Rabbit_GTI)*

just started it this morning nice and cold and it was making a whistling noise out of the adjust screw on the throttle body and the idle was slowly climbing. So Iam going to guess that the adjustment screw o-ring is fubar.


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## wclark (Mar 28, 2001)

*Re: NEUSPEED Throttle Body Help. (White_Rabbit_GTI)*

If this is a VW-looking design then the O ring is probably the culprit. If it is whistling it must be really bad - or missing. I think most people just take the one in there to the hardware store and buy something similar.
You can use a silicone sealer or RTV in a pinch if you cant locate an O-ring. Adjust the screw where you want it (engine warmed up). Shut the engine off and cover the screw head and the recess around it with sealant then let it set up. Dont remove the screw and add sealant because cleaning it out to use an new O-ring later is impossible. If applied to the surface after the screw is in place you wont get much down in the O-ring seat area. 
If yours is whistling then it would be a good idea to hold your thumb over the screw recess after adjustment to seal it before deciding the screw is where you want it.


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## White_Rabbit_GTI (Apr 27, 2007)

*Re: NEUSPEED Throttle Body Help. (wclark)*

I think Iam going to remove the screw take it with me to a local wholesale parts distributor and get 2 of ever single o-ring that looks close from the smallest of the small all the way to the biggest looking one that will still fit.


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## White_Rabbit_GTI (Apr 27, 2007)

*Re: NEUSPEED Throttle Body Help. (White_Rabbit_GTI)*

Just got the bitch running turns out the threads on the idle screw are a tad worn and it kept backing itself out at an alarming rate. tok care of it with some teflon tape.


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## Napalm Burns MK2 (Aug 31, 2007)

Is there any special instructions that I should follow when installing this ? Also are there gaskets I can purchase for the adapter plate and so on ? 
Thanks


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## VDub2625 (Jan 4, 2003)

*Re: (Napalm Burns MK2)*

By the way, the screw is not the mixture adjustment. It's just the air bypass screw. The farther out it is, the more air bleeds past the throttle for idle. Vibration can cause the screw to back out if the o-ring is bad (and air can leak past the screw itself from the outside air if the o-ring is bad too).
EDIT: realized this is an old topic, but I figured it could use some correcting







as for the special instructions, no, it's not that hard to install, just bolt on. As for gaskets, if it truly is just an A2-sized throttle 9which is bigger then mk2 throttles), then you should be able to use Mk2 gaskets.


_Modified by VDub2625 at 11:27 AM 12-11-2007_


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## antichristonwheels (Jun 14, 2001)

*Re: NEUSPEED Throttle Body Help. (wclark)*

NO NO NO RTV will ruin your O2 sensor.


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## chois (May 12, 2000)

O2 sensor safe sealant is readily available. Don't buy anything else, then you won't accidentally use the wrong stuff in the wrong place.


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## ABA Scirocco (May 30, 2001)

*Re: (chois)*

Don't use RTV on that screw, even the sensor safe stuff, it's REALLY not necessary. A good tight fitting o-ring will provide more than enough friction to prevent the screw from backing out even if the tthreads are a little too loose. Just take the screw out, remove the o-ring, take it to your local hardware store, most stores will have a selection o-rings in various sizes, pick the one that's the closest match, install it and everything will be golden, probably won't cost you more than 25-50¢.


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## wclark (Mar 28, 2001)

*Re: (ABA Scirocco)*

Good caution about RTV. Some will outgas silicone and if that finds its way onto the O2 sensor, it will cause it to fail. 
As I said - in a pinch - it can be used. Permatex makes a couple RTV that are specifically listed as sensor safe...80022 and 81422 for instance.


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## ABA Scirocco (May 30, 2001)

*Re: (wclark)*

I just thought of one more option that my be open to the OP. Since this is a problem only with the new throttle body, the o-ring on the idle screw of the original throttle body is probably still good, pull the screw out of the original throttle body and install it in the Neuspeed one.


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