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Re: Need help fine-tuning my idle RPM
[Re: jb500]
#1946152
11/06/15 08:08 AM
11/06/15 08:08 AM
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Joined: Jan 2003
Posts: 17,929
Akron, Ohio
ProSport
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OP
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Joined: Jan 2003
Posts: 17,929
Akron, Ohio
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While you have the carb apart, take a look at the idle feed passageways on the main body. I too have a Pro-Sys 950 and found that the secondary side had reducer plugs installed in the idle passageways. Removed them and the engine idles much better in gear. It now gets the fuel it was starving for and took away the eye buring lean mixture I chased for a while.
Crap, wish I'd seen this before I put it back together last night and went cruising lol. Sounds like something worth looking into.
1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
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Re: Need help fine-tuning my idle RPM
[Re: jb500]
#1946296
11/06/15 01:27 PM
11/06/15 01:27 PM
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Joined: Jul 2004
Posts: 19,318
State of confusion
Thumperdart
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I Live Here
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While you have the carb apart, take a look at the idle feed passageways on the main body. I too have a Pro-Sys 950 and found that the secondary side had reducer plugs installed in the idle passageways. Removed them and the engine idles much better in gear. It now gets the fuel it was starving for and took away the eye buring lean mixture I chased for a while.
Got a pic I`m trying to visualize what you`re talking about? Do you mean plugs in the emul. holes? Or the ifr brass plugs? ProSport.....by blocking/pluggin the sec. holes you made it richer and for me when the idle wanders as you stated, it`s USUALLY a bit lean.......
Last edited by Thumperdart; 11/06/15 01:28 PM.
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Need help fine-tuning my idle RPM
[Re: ProSport]
#1946312
11/06/15 01:49 PM
11/06/15 01:49 PM
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Joined: Jan 2003
Posts: 17,929
Akron, Ohio
ProSport
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OP
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That makes sense, thanks.
1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
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Re: Need help fine-tuning my idle RPM
[Re: Thumperdart]
#1946369
11/06/15 03:18 PM
11/06/15 03:18 PM
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Joined: Jul 2007
Posts: 202
TN Hoosier
jb500
enthusiast
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enthusiast
Joined: Jul 2007
Posts: 202
TN Hoosier
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While you have the carb apart, take a look at the idle feed passageways on the main body. I too have a Pro-Sys 950 and found that the secondary side had reducer plugs installed in the idle passageways. Removed them and the engine idles much better in gear. It now gets the fuel it was starving for and took away the eye buring lean mixture I chased for a while.
Got a pic I`m trying to visualize what you`re talking about? Do you mean plugs in the emul. holes? Or the ifr brass plugs? ProSport.....by blocking/pluggin the sec. holes you made it richer and for me when the idle wanders as you stated, it`s USUALLY a bit lean....... In the actual main body, not the metering plates. There were two 8-32 plugs (forget the drill size) installed into the idle passageways on the secondary side. They tapped the body and put in the orifice plugs to restrict idle flow.
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Re: Need help fine-tuning my idle RPM
[Re: jb500]
#1946462
11/06/15 05:06 PM
11/06/15 05:06 PM
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Joined: Jul 2004
Posts: 19,318
State of confusion
Thumperdart
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I Live Here
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Posts: 19,318
State of confusion
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Later today when I can get to a computer. Cool, thankxxx.......Someone brought me a DaVince carb to check out and I gave it back cos there were holes and plugs in funny places and couldn`t put my name on it.......
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Need help fine-tuning my idle RPM
[Re: Thumperdart]
#1946665
11/06/15 10:33 PM
11/06/15 10:33 PM
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Joined: Jul 2007
Posts: 202
TN Hoosier
jb500
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enthusiast
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TN Hoosier
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Later today when I can get to a computer. Cool, thankxxx.......Someone brought me a DaVince carb to check out and I gave it back cos there were holes and plugs in funny places and couldn`t put my name on it....... I grabbed an often used Holley diagram rather than pull apart my carb. The two plugs (.035 orifice) were installed into the ports labled #3 (top pic on sheet) on the secondary side.
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Re: Need help fine-tuning my idle RPM
[Re: jb500]
#1946699
11/06/15 11:29 PM
11/06/15 11:29 PM
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Joined: Jul 2004
Posts: 19,318
State of confusion
Thumperdart
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I Live Here
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Ya, that`s a first for me I usually drill/tap the t-slot hole next to it..........
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Need help fine-tuning my idle RPM
[Re: ProSport]
#1946701
11/06/15 11:30 PM
11/06/15 11:30 PM
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Joined: Jul 2007
Posts: 202
TN Hoosier
jb500
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My combo is pretty close to yours: 10.5:1 263@.050 Dynamic Vert Initial: 25deg Total: 38deg Carb: IFR: 0.035 moved to bottom of metering block IAB: 73 x 4 MAB: 28 x 4 Throttle plates drilled. Idles in gear around 950rpm showing about 13.5 on the AFR gauge.
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Re: Need help fine-tuning my idle RPM
[Re: ProSport]
#1946753
11/07/15 12:58 AM
11/07/15 12:58 AM
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Joined: Jan 2003
Posts: 17,929
Akron, Ohio
ProSport
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Very similar combo for sure, post pics of your car and engine on this thread if you don't mind, I'd like to see them.
Your IAB's are way bigger than mine, I'll check for those restrictors in my main body, if I remove them I'll probably have to change my IAB's.?
1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
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The taper of the adj. screw limits/adds fuel as needed so makes no sense to me unlike the t-slot which has no adjustments. 