Throttle body question, 1988 model

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Jul 4, 2002 | 08:26 PM

needanother1

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Racer

Joined: Jul 2002

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From: Paris AR, USA

Throttle body question, 1988 model

New to the forum: Hello everyone, from a fellow Corvette nut!

I've discovered that my TPI throttle body has quite a lot of wear around the throttle shaft. Seems to be causing erratic idle speed. Is there a replaceable bushing there, so that it can be rebuilt? If not, where would I look for a replacement TB? I have no need for a 52mm, and I've heard many of the new ones are junk anyway. Suggestions?

Thanks,
Jason

Jul 5, 2002 | 09:58 AM

Vic'89

Safety Car

Joined: Jun 2000

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From: Long Island, NY

Re: Throttle body question, 1988 model (needanother1)

If you want to stay with a 48mm TB, look for a used one.

Vic

Jul 5, 2002 | 12:11 PM

needanother1

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Racer

Joined: Jul 2002

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From: Paris AR, USA

Re: Throttle body question, 1988 model (Vic'89)

Thanks for the reply. I take that to mean that they're not easily re-buildable?

Jul 5, 2002 | 02:02 PM

UDLUV12

Racer

Joined: Jul 2000

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From: Glen Burnie Md

Re: Throttle body question, 1988 model (needanother1)

Jason,
I seriously doubt that a little bit of wear is going to cause you the iratic idle you are describing.
Since you have an '88 Vette, I'd be more inclined to think the injectors need a thorough cleaning, and at the same time you're having them cleaned, remove your throttle body, and clean that too. Do the job right, and remove the throttle body. I have seen other Vette owners try to 'clean' their units while still mounted. I just shake my head at this time waste.
You didn't mention the mileage on your '88, so I'm thinking it's probably over 100K?
Don't waste your money on new injectors or a new TB. Get 'em cleaned first. You already have one of the best injectors GM has ever made (that comes from Rich at Cruzin Performance [www.cruzinperformance.com}), who is a source to have your injectors cleaned, and blueprinted. He does a hell-uva job for $80 plus S&H.
Good Luck!!
John

[Modified by UDLUV12, 12:23 PM 7/5/2002]

Jul 5, 2002 | 02:53 PM

needanother1

Thread Starter

Racer

Joined: Jul 2002

Posts: 269

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From: Paris AR, USA

Re: Throttle body question, 1988 model (UDLUV12)

Thank you for the additional information. My '88 has 130K on it, so all the information you mentioned applies. Instead of "erratic" idle, I should have described it as an occasional high idle that can be slowed down by pushing backwards on the throttle shaft where the cables hook on. There's a lot of play there, probably close to 1/4", and that's the reason I think replacing the TB would be a good place to start. The TPS and the IAC are fairly new, the TPS adjustment has been checked and the plug is still covering the minimum idle screw. The car runs fine except that sometimes it wants to idle about 1500 rpm.

I've had a '74 L-48 and LT1's and LS1's in F-bodies, but this is my first L-98.
Still learning, and I appreciate the help!

Jason

Jul 5, 2002 | 03:02 PM

PeteL

Le Mans Master

Joined: Dec 1999

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From: And on the fifth day, subpoenas were served to Obama senior staff

Re: Throttle body question, 1988 model (needanother1)

Had the same thing on my 89. Replaced the throttle body. I am sure it can be repaired, I just couldn't find anybody to do it.

I also got the gasket set and a set of screws for the coolant plate (mine fairly buggered up and did not want to mess up the new TB).

Try Jeff Koop on this forum for good pricing.

Good Luck

Pete

Jul 5, 2002 | 03:21 PM

Skippy Stone

Racer

Joined: Jul 2002

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From: Aptos CA

Re: Throttle body question, 1988 model (needanother1)

Quote:

...There's a lot of play there, probably close to 1/4", and that's the reason I think replacing the TB would be a good place to start. The TPS and the IAC are fairly new, the TPS adjustment has been checked and the plug is still covering the minimum idle screw. The car runs fine except that sometimes it wants to idle about 1500 rpm.

Jason

1. Where is the play in the body or the cable? The cable has play. There is a re-build kit (or use to be). I'm not sure you need it. Clean it up really good.

2. This may have nothing to do with the TB. A. The ECM controls a lot of this kind of thing. B. You may need to reset you IAC. Start your car with part throttle run for 5 seconds. Shut it off. Start it again after 10 seconds. This should reset the IAC.

(Some IACs reset by putting it to floor with engine off, iginition on, let off throttle and then start.)

Jul 6, 2002 | 12:00 PM

dlmeyers

Burning Brakes

Joined: Feb 2000

Posts: 824

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From: Camden SC

Re: Throttle body question, 1988 model (Skippy Stone)

Read a post some time back about a guy who took his throttle body (worn shaft housing) to a carburator repair shop. They drilled out the hole, installed a bushing, off he went. Believe it was under $60. Tolerances were like new. Lucky dude.

Hope you get it fixed.

dlmeyers 90 coupe zf6 3 speed shocks