Hood Flap on 73 Coupe
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 23
Likes: 1
From: Indiana
Hood Flap on 73 Coupe
Hi All,
Need some help/advice on trying to diagnose why my hood flap is not opening when throttle is mashed.
My understanding is there is a switch on the gas pedal that is activated when the pedal is pushed so far down. A solinoid then is activated mounted on the underside of the hood that opens the hood flap.
Can I turn the key on, but not start the engine, and be able to activate the switch and solenoid? Just trying to figure out the easiest way to start on diagnosing where the issue may lie.
Need some help/advice on trying to diagnose why my hood flap is not opening when throttle is mashed.
My understanding is there is a switch on the gas pedal that is activated when the pedal is pushed so far down. A solinoid then is activated mounted on the underside of the hood that opens the hood flap.
Can I turn the key on, but not start the engine, and be able to activate the switch and solenoid? Just trying to figure out the easiest way to start on diagnosing where the issue may lie.
Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
apply 12 volts to the solenoid to check it's operation, if it moves then it is ok, then start tracing back to see what is missing or broken. Have a 12 volt test light??? make sure to find a good ground to use the test light.
Le Mans Master
Joined: May 2008
Posts: 9,063
Likes: 2,736
2022 C3 of the Year Finalist - Modified
Not to hijack this thread, but might change the thought process on fixing it, if cold air induction is better for power, WHY was this system designed to only operate at full throttle.......would cold air not be better at all throttle settings.....?? If I owned a C3 with this system, I would modify the system to have the flap open ALL THE TIME. Hell, take the flap out to provide less restrictive cold air intake. What's the downside? I hope the answer is not "noise", because that is a joke. It may have been a reason for GM to design it to meet required noise emissions, but is irrelevant to real people.
Last edited by Shovels and Vettes; Jan 13, 2018 at 09:52 AM.
Burning Brakes
Joined: Sep 2005
Posts: 1,050
Likes: 205
From: Lewes Delaware
Yes, you can turn the key to “On” (and not start the engine) to activate it.
Check the carpet under the accelerator pedal to make sure it is not bunching to interfere with the pedal pushing on the switch.
Fran
Burning Brakes
Joined: Oct 2013
Posts: 1,114
Likes: 520
From: McClellandtown, Pa.
You may need to reset the switch. According to the AIM, if you press the plunger as far forward as possible, this will preset the switch. The switch should readjust itself with the first wide open throttle attempt by pushing the accelerator pedal to the floor.
You could also try to cheat the process by sliding a little piece of rubber hose over the plunger where the pedal linkage hits it. If your switch and hood solenoid are ok, you should hear the thud under the hood when the solenoid kicks in to open the Induction door! Here's a photo of the switch with a piece of ( vacuum hose). Note: This switch also doubles as the 'kickdown' switch. If you need to replace yours, that's how it is listed by all the vendors.
Hope this helps,
Tooch
You could also try to cheat the process by sliding a little piece of rubber hose over the plunger where the pedal linkage hits it. If your switch and hood solenoid are ok, you should hear the thud under the hood when the solenoid kicks in to open the Induction door! Here's a photo of the switch with a piece of ( vacuum hose). Note: This switch also doubles as the 'kickdown' switch. If you need to replace yours, that's how it is listed by all the vendors.
Hope this helps,
Tooch
Last edited by Tooch1; Jan 14, 2018 at 08:38 AM.
Melting Slicks
Joined: Oct 2013
Posts: 2,569
Likes: 126
From: San Diego California
You could also try to cheat the process by sliding a little piece of rubber hose over the plunger where the pedal linkage hits it. If your switch and hood solenoid are ok, you should hear the thud under the hood when the solenoid kicks in to open the Induction door! Here's a photo of the switch with a piece of ( vacuum hose). Note: This switch also doubles as the 'kickdown' switch. If you need to replace yours, that's how it is listed by all the vendors.
Hope this helps,
Tooch
Hope this helps,
Tooch
Steve
BTW: I wondered what that wire from my TH400 was, until the shop told me it was the kickdown input.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 23
Likes: 1
From: Indiana
Great info, thanks so much, tooch1!
You may need to reset the switch. According to the AIM, if you press the plunger as far forward as possible, this will preset the switch. The switch should readjust itself with the first wide open throttle attempt by pushing the accelerator pedal to the floor.
You could also try to cheat the process by sliding a little piece of rubber hose over the plunger where the pedal linkage hits it. If your switch and hood solenoid are ok, you should hear the thud under the hood when the solenoid kicks in to open the Induction door! Here's a photo of the switch with a piece of ( vacuum hose). Note: This switch also doubles as the 'kickdown' switch. If you need to replace yours, that's how it is listed by all the vendors.
Hope this helps,
Tooch
You could also try to cheat the process by sliding a little piece of rubber hose over the plunger where the pedal linkage hits it. If your switch and hood solenoid are ok, you should hear the thud under the hood when the solenoid kicks in to open the Induction door! Here's a photo of the switch with a piece of ( vacuum hose). Note: This switch also doubles as the 'kickdown' switch. If you need to replace yours, that's how it is listed by all the vendors.
Hope this helps,
Tooch
