89 350tpi wont idle with holley TB
11-24-2014, 11:01 AM
#1
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Location: FL
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Car: 89 formula
Engine: 350 tpi
Transmission: T5
Axle/Gears: 3.73
89 350tpi wont idle with holley TB
Hey guys,
I have a 89 formula 350tpi it has aluminum heads, comp 480 cam (has a nice rough idle) , full exhaust with true dual flowmasters, ported plenum and intake base, slp runners and 24 lb injectors, custom chip, blah blah blah. The car ran good with the stock TB. I purchased a 52 mm holley tb installed it (I have new TPS and IAC both AC delco and SET PROPERLY they were on my old TB before) now I cant get the it to idle right if I hold my foot on the gas it will idle. I turned the idle screw all the way and it doesn't seem like the screw is long enough. I heard people on this forum drilling a hole in the plenum for the IAC do I need to do this? or use a longer idle stop screw? or both?
I have a 89 formula 350tpi it has aluminum heads, comp 480 cam (has a nice rough idle) , full exhaust with true dual flowmasters, ported plenum and intake base, slp runners and 24 lb injectors, custom chip, blah blah blah. The car ran good with the stock TB. I purchased a 52 mm holley tb installed it (I have new TPS and IAC both AC delco and SET PROPERLY they were on my old TB before) now I cant get the it to idle right if I hold my foot on the gas it will idle. I turned the idle screw all the way and it doesn't seem like the screw is long enough. I heard people on this forum drilling a hole in the plenum for the IAC do I need to do this? or use a longer idle stop screw? or both?
11-25-2014, 12:11 PM
#2
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Join Date: Aug 2014
Location: FL
Posts: 11
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Car: 89 formula
Engine: 350 tpi
Transmission: T5
Axle/Gears: 3.73
Re: 89 350tpi wont idle with holley TB
Hey guys,
I have a 89 formula 350tpi it has aluminum heads, comp 480 cam (has a nice rough idle) , full exhaust with true dual flowmasters, ported plenum and intake base, slp runners and 24 lb injectors, custom chip, blah blah blah. The car ran good with the stock TB. I purchased a 52 mm holley tb installed it (I have new TPS and IAC both AC delco and SET PROPERLY they were on my old TB before) now I cant get the it to idle right if I hold my foot on the gas it will idle. I turned the idle screw all the way and it doesn't seem like the screw is long enough. I heard people on this forum drilling a hole in the plenum for the IAC do I need to do this? or use a longer idle stop screw? or both?
I have a 89 formula 350tpi it has aluminum heads, comp 480 cam (has a nice rough idle) , full exhaust with true dual flowmasters, ported plenum and intake base, slp runners and 24 lb injectors, custom chip, blah blah blah. The car ran good with the stock TB. I purchased a 52 mm holley tb installed it (I have new TPS and IAC both AC delco and SET PROPERLY they were on my old TB before) now I cant get the it to idle right if I hold my foot on the gas it will idle. I turned the idle screw all the way and it doesn't seem like the screw is long enough. I heard people on this forum drilling a hole in the plenum for the IAC do I need to do this? or use a longer idle stop screw? or both?
11-25-2014, 07:54 PM
#3
Re: 89 350tpi wont idle with holley TB
I wouldn't touch the idle screw. If you hold the blades open far enough it defeats the purpose of the ecm changing anything. As far as drilling the plenum, if you have the correct year TB then I would thing the plenum would not need to be drilled. I've never dealt with the Holley TB so I can't give you first hand experience. I would take the TB back off and check the idle passages, see where they run and if anything is blocked off by gasket, plenum or what have you.
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