Need help cleaning the TB.
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Instructor
Joined: Jun 2002
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Need help cleaning the TB.
While doing the TB bypass mod I notice that the TB was pretty dirty. I read last week about someone taking apart and cleaning the TB. If anyone has instructions on the dissasembly I would appreciate it. :lol:
Burning Brakes
Joined: Apr 2002
Posts: 755
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From: Patterson CA
Re: Need help cleaning the TB. (champs_97)
Champs,
Somebody here on the forum sent me this awhile back but I don't remember who, (Thanks whoever it was), I followed the process except I pull the TPS off before I cleaned the TB. If you do this, make sure you have a multi-meter to readjust the TPS when you reconnect everything. Also, be very careful with the IAC valve, it's about $90 for a new one. DON'T push on the pintle of an old one, it could VERY EASILY damage it!
Anyway, here goes, it's LONG WINDED:
Throttle Body maintenance:
Using your screwdriver remove the air duct and MAF sensor in front of the throttle body, now open the throttle by hand (engine off of course) and feel behind the throttle blades. Did your fingers go all black and gungy (yucky isn't it). You need to get that throttle body off and scrub it cleaner than clean can be. Preparation: Go and buy some carburetor cleaner (best in spray cans), and buy yourself a new toothbrush, your old one just got a new life.
Get an old bowl or something similar, rags and perhaps some of those lovely rubber surgical gloves. Getting right on in there remove the 3 pin connector from the throttle position sensor, and remove all the pipe work going to the throttle body, there is a little water spillage, not much. Also remove the IAC connector (a 4 wire square connector) it's a bit fiddly to get to. Now the tricky part, the throttle cables need to be released, (manual and auto cars are different), the cables are fixed with wonderful things called Jesus clips, you slide a screwdriver under it and ping it disappears, you mutter 'Jesus where did that go' - what a name for an item. Best to cover the area with a cloth to capture any pinging that goes on.
With the cables released the throttle body should be free to remove. Undo the four long bolts holding it to the plenum, careful when prizing it apart, do not damage the gasket. Now you thought you were clear didn't you, nope, GM put a little booby trap underneath. There is a small vacuum tube with a rubber elbow that needs to be pulled off. You're free!
The filthy part. Now comes the really dirty part. Put the throttle body in the bowl and spray with carb cleaner and scrub like crazy, especially around the throttle blades. Its great, really messy but the final spray just cleans it all off and there you have a gleaming throttle body.
Now using a 31 or 32mm spanner remove the IAC valve (that's the large black looking thing on the side), mind the gasket. Clean the spring and pintle and if you can get inside the orifice (ooooh don't you luv that word) and clean the seat area (!). Make sure that the small hole going from the throttle mouth to the IAC is clear. Finally just spray the spring and pintle with WD40 and replace the IAC valve.
Final check - and perhaps another blast with the cleaner to remove any surface muck still there. You may want to soak a rag with carb cleaner and clean as far in the plenum as you can get. Allow to dry and replace the throttle body on the plenum, taker great car with the gasket ensure it is positioned correctly. Ensure all the connectors cables and pipes are back on (don't forget the little tube underneath).
This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on, measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.
Self satisfaction. Job done now you should start your Corvette and stand back to admire the even tickover and you will marvel at the smooth response the car now seems to have. If nothing else you have pampered and tinkered for about an hour, got filthy, therefore justifying your time and got a tangible result afterwards, all that remains to do is test drive the car to the nearest (or in fact not so nearest pub). Congratulate yourself with a beer and apply wide beaming grin.
Don't forget to put that little vacuum hose back on the underside of the TB. And, I replaced all the gaskets while I had it apart.
Good Luck - :smash:
Somebody here on the forum sent me this awhile back but I don't remember who, (Thanks whoever it was), I followed the process except I pull the TPS off before I cleaned the TB. If you do this, make sure you have a multi-meter to readjust the TPS when you reconnect everything. Also, be very careful with the IAC valve, it's about $90 for a new one. DON'T push on the pintle of an old one, it could VERY EASILY damage it!
Anyway, here goes, it's LONG WINDED:
Throttle Body maintenance:
Using your screwdriver remove the air duct and MAF sensor in front of the throttle body, now open the throttle by hand (engine off of course) and feel behind the throttle blades. Did your fingers go all black and gungy (yucky isn't it). You need to get that throttle body off and scrub it cleaner than clean can be. Preparation: Go and buy some carburetor cleaner (best in spray cans), and buy yourself a new toothbrush, your old one just got a new life.
Get an old bowl or something similar, rags and perhaps some of those lovely rubber surgical gloves. Getting right on in there remove the 3 pin connector from the throttle position sensor, and remove all the pipe work going to the throttle body, there is a little water spillage, not much. Also remove the IAC connector (a 4 wire square connector) it's a bit fiddly to get to. Now the tricky part, the throttle cables need to be released, (manual and auto cars are different), the cables are fixed with wonderful things called Jesus clips, you slide a screwdriver under it and ping it disappears, you mutter 'Jesus where did that go' - what a name for an item. Best to cover the area with a cloth to capture any pinging that goes on.
With the cables released the throttle body should be free to remove. Undo the four long bolts holding it to the plenum, careful when prizing it apart, do not damage the gasket. Now you thought you were clear didn't you, nope, GM put a little booby trap underneath. There is a small vacuum tube with a rubber elbow that needs to be pulled off. You're free!
The filthy part. Now comes the really dirty part. Put the throttle body in the bowl and spray with carb cleaner and scrub like crazy, especially around the throttle blades. Its great, really messy but the final spray just cleans it all off and there you have a gleaming throttle body.
Now using a 31 or 32mm spanner remove the IAC valve (that's the large black looking thing on the side), mind the gasket. Clean the spring and pintle and if you can get inside the orifice (ooooh don't you luv that word) and clean the seat area (!). Make sure that the small hole going from the throttle mouth to the IAC is clear. Finally just spray the spring and pintle with WD40 and replace the IAC valve.
Final check - and perhaps another blast with the cleaner to remove any surface muck still there. You may want to soak a rag with carb cleaner and clean as far in the plenum as you can get. Allow to dry and replace the throttle body on the plenum, taker great car with the gasket ensure it is positioned correctly. Ensure all the connectors cables and pipes are back on (don't forget the little tube underneath).
This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on, measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.
Self satisfaction. Job done now you should start your Corvette and stand back to admire the even tickover and you will marvel at the smooth response the car now seems to have. If nothing else you have pampered and tinkered for about an hour, got filthy, therefore justifying your time and got a tangible result afterwards, all that remains to do is test drive the car to the nearest (or in fact not so nearest pub). Congratulate yourself with a beer and apply wide beaming grin.
Don't forget to put that little vacuum hose back on the underside of the TB. And, I replaced all the gaskets while I had it apart.
Good Luck - :smash:
