1996 Tps Wot
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Intermediate
Joined: Feb 2005
Posts: 44
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From: Marietta GA
1996 Tps Wot
I've got a 1996 CE LT4 that has a Holley 52mm throttle body on it. The car idles perfectly - maintains ~700 with the AC off with an IAC count of ~45. However, with the peddle pressed to the floor the TPS registers 85% throttle. The throttle value was read using a laptop scanner package from www.obd-2.com (this value came from the ECM, not directly from the TPS).
From what I've read, the 1996 LT4 does not have an adjustable TPS. I think this may be an issue of the throttle cable being adjusted incorrectly (too long). Has anyone had a similar issue with the Holley 52mm throttle body, and if so how was the problem remedied?
Thanks in advance for your help.
From what I've read, the 1996 LT4 does not have an adjustable TPS. I think this may be an issue of the throttle cable being adjusted incorrectly (too long). Has anyone had a similar issue with the Holley 52mm throttle body, and if so how was the problem remedied?
Thanks in advance for your help.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 59
From: Fremont Oh
Your correct...
They are not adjustable, the tps "re-zeros" . If you set your idle it will reset the TPS voltage....
i have a BBK and mine will register 100% I had a heck of a time getting ~ 40 IAC...
Mo
They are not adjustable, the tps "re-zeros" . If you set your idle it will reset the TPS voltage....
i have a BBK and mine will register 100% I had a heck of a time getting ~ 40 IAC...
Mo
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
I think the first thing you should do is take off your intake duct and have someone press the pedal down. If you do a search almost EVERY single 58mm and some 52mm Throttle bodies from BBK, AS&M and HOLLEY, Do not open 100% . My holley opened to 85% and I tried searching for an alternative until I found a Callaway unit that opened all the way without having to come up with my own method to do so. So it may not be your tps, it may just be the crappy quality of the TB you have.
Also remember the stock TBs are closed at a 15 degree angle or so. If your aftermarket TB is closed 'straight' up, there's why your tps isn't working right. And when your tps isn't working right, you're not going to get optimum timing/fuel.
Also remember the stock TBs are closed at a 15 degree angle or so. If your aftermarket TB is closed 'straight' up, there's why your tps isn't working right. And when your tps isn't working right, you're not going to get optimum timing/fuel.
Thread Starter
Intermediate
Joined: Feb 2005
Posts: 44
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From: Marietta GA
Update
I received an e-mail from Holley's customer service today stating that the 52mm throttle body for the 94-97 LT1 (part number 112-508) is only for use in F-body cars due to the geometry of the Corvette linkage. In my past reading it seemed as thought several people on the forum were using this TB on the later LT1's (94-96) with few reported problems.
For those of you using the Holley throttle body, what if any modifications were performed to achieve 100% throttle opening? I'll be tinkering with the throttle cable adjustments tomorrow to try and get the TB to work correctly. I'm looking for any help/ideas at all short of "you have to buy another throttle body".
Thanks in advance!
For those of you using the Holley throttle body, what if any modifications were performed to achieve 100% throttle opening? I'll be tinkering with the throttle cable adjustments tomorrow to try and get the TB to work correctly. I'm looking for any help/ideas at all short of "you have to buy another throttle body".
Thanks in advance!
Thread Starter
Intermediate
Joined: Feb 2005
Posts: 44
Likes: 1
From: Marietta GA
Final Update
Here's the final update on the Holley 52mm throttle body/96 LT4 situation:
I've swapped back to a used BBK 52mm throttle body I had sitting on a shelf. The BBK needed the IAC passages drilled out in order to idle correctly, but now it works like a charm. It's not as pretty as the Holley, but it works!
For any 1996 LTx owners that are thinking about purchasing the Holley 112-508, be aware that this throttle body is NOT designed for use on a 'Vette and will not open fully without modifications.
I've swapped back to a used BBK 52mm throttle body I had sitting on a shelf. The BBK needed the IAC passages drilled out in order to idle correctly, but now it works like a charm. It's not as pretty as the Holley, but it works!
For any 1996 LTx owners that are thinking about purchasing the Holley 112-508, be aware that this throttle body is NOT designed for use on a 'Vette and will not open fully without modifications.
