Replacing the Throttle Body

by Scott Fabre

Last Update: 08/04/2005

The reason I am replacing the throttle assembly is to get rid of a pesky high idle that occurs when I come to a stop after driving above 50mph or so.

The new throttle assembly all ready to go. I have already removed the bellows.	There are five screws that hold the air horn to the throttle assembly. Once removed you can disconnect the MAT sensor electrical connector and the large vacuum hose above.	The Once the air horn is moved out of the way you can see that there is a small hose which connects to the under side of the air horn.
This is a view of the throttle assembly. Note the two large black torque head bolts close to the center of the throttle assembly. There are two more of these on the outer edges.	The another view of the small vacuum hose. Don't forget to reattach it when reassembling.	The back of the air horn. I study it carefully in order to recreate a new gasket.
The four bolts to remove are indicated.	The small radiator hose on the driver's side should be clamped off to prevent a mess.	The four bolts are size T-40.
The four bolts are out.	By placing the the new throttle body on some 1/16 in thick gasket material you can trace out a new one.	Just a little cutting and you are done.
The torque setting is 20 ft/lbs for the four bolts.	The new assembly is in. Now it is time to reattach all the goodies.	The air horn and bellows go in quickly as do the electrical connectors and vacuum hoses. That's it.

Now all I have to do is calibrate the throttle position sensor. That is a different "How to". The symptom of having an idle that stuck at 2000 rpm for a bit each time I drove it is fixed. Upon examination of the old assembly I indeed did find a problem. The passenger side butterfly plate was sticking due to slop in the shaft that the plates are screwed to. There is a sleeve that the shaft goes through that is obviously warn.


	Disclaimer: Repairs and techniques are reported here by amateurs and professionals as an informational opinion service only and should not be attempted by other than factory trained and certified technicians. The ZR1 Net does not recommend anyone doing these procedures and is not responsible for any adverse outcome. Factory repair manuals should always be used and followed to the letter in conjunction with any repair or maintenance performed. All cautions and warnings that appear in the factory manuals apply here as well. As recommended in all service manuals, proper eye and body protection as well as proper tools must be used for any maintenance performed by individuals. Working on automobiles is dangerous and could result in personal and/or property injury. If you do not have the proper tools or know-how, you should not do any of these procedures, but have a qualified technician perform the work.

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