What is the carb throttle solenoid connection for?
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sargentrs
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What is the carb throttle solenoid connection for?
'70 sport custom. 302, 3 on the tree, Ford 3.03 tranny, autolite 2100 carb. Just out tinkering with the old girl and noticed a wire I forgotten about. Diagram says it's the carb throttle solenoid connection. Green wire, fattest in the 4 wire harness coming from the firewall to the engine. Never have had it hooked up but was just curious so thought I'd ask. What's it for? Is it hot all the time or just when the ignition's on? Thanks in advance! Randy
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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70_F100
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Re: What is the carb throttle solenoid connection for?
Some of the early 70's model vehicles had curb idle speeds that were so high (to meet emissions standards) that when the engine was turned off, they continued to run (dieseling).
In order to correct this problem, while still meeting EPA standards, a solenoid was used as the idle stop when the engine was running. When the engine was turned off, the solenoid would retract, allowing the throttle plates to close. This prevented the engine from getting any air (and likewise, fuel) when the ignition was turned off.
Some manufacturers also used the same concept on vehicles with air conditioning to open the throttle slightly more when the compressor was on.
The wire should only have power when the ignition switch is on.
In order to correct this problem, while still meeting EPA standards, a solenoid was used as the idle stop when the engine was running. When the engine was turned off, the solenoid would retract, allowing the throttle plates to close. This prevented the engine from getting any air (and likewise, fuel) when the ignition was turned off.
Some manufacturers also used the same concept on vehicles with air conditioning to open the throttle slightly more when the compressor was on.
The wire should only have power when the ignition switch is on.
Wise men talk because they have something to say; fools talk because they have to say something.--Plato
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???
That's not an oil leak
That's SWEAT from all that HORSEPOWER!! 
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???
That's not an oil leak
That's SWEAT from all that HORSEPOWER!! -
sargentrs
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Re: What is the carb throttle solenoid connection for?
Great explanation! Thanks!
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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sargentrs
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Re: What is the carb throttle solenoid connection for?
Must've been bad. Unhooked it and plugged the vacuum port and she runs a LOT smoother! Thanks!
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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Dragon
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Re: What is the carb throttle solenoid connection for?
I use that wire to run my electric choke.
Old Fords Rule
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Was a Ford Service Tech
71 F250 with Shell Car 390 NP435 Dana 60 3.73s, PS, PB, 750 EC VS Holley Accel Points Eliminator.
98 Volvo S70 2.4T Auto
71 Service manuals Volumes 1,2,3 and 4 So ask away.
My Gallery
Spark test
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sargentrs
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Re: What is the carb throttle solenoid connection for?
Glad you mentioned that! My choke doesn't work and I thought about hooking up a new one with that connection. Thanks!Dragon wrote:I use that wire to run my electric choke.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.