Throttle body supplemental spring / stiff gas pedal |
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Throttle body supplemental spring / stiff gas pedal |
sfrenck |
Dec 5 2010, 07:00 PM
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#1
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Just started driving my "project" ('73 2.0L with 74' F.I. setup) up and down the block for my preliminary road test. One thing I noticed, and my 79 yr. old father really noticed, was the gas pedal was very stiff.
I have already replaced the plastic bushings in the pedal cluster with the brass rebuild kit. Tonight, I disconnected the throttle cable from the throttle body and confirmed the cable / pedal was not the issue. It seems that the supplemental spring on the throttle body is the culprit. Is there a different, easier spring that I can install or is a stiff gas pedal just part of the normal Porsche engineering? Or, should I look for a '73 throttle body without the supplemental spring? Thanks - Scott |
1988Hawk |
Dec 5 2010, 07:10 PM
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#2
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Newbie Group: Members Posts: 41 Joined: 17-April 08 From: Chicago Member No.: 8,929 Region Association: None |
Just started driving my "project" ('73 2.0L with 74' F.I. setup) up and down the block for my preliminary road test. One thing I noticed, and my 79 yr. old father really noticed, was the gas pedal was very stiff. I have already replaced the plastic bushings in the pedal cluster with the brass rebuild kit. Tonight, I disconnected the throttle cable from the throttle body and confirmed the cable / pedal was not the issue. It seems that the supplemental spring on the throttle body is the culprit. Is there a different, easier spring that I can install or is a stiff gas pedal just part of the normal Porsche engineering? Or, should I look for a '73 throttle body without the supplemental spring? Thanks - Scott Make sure that the pedal board is not interfering with the pedal action, move the board as far right as you can. |
sfrenck |
Dec 5 2010, 08:08 PM
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#3
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Just started driving my "project" ('73 2.0L with 74' F.I. setup) up and down the block for my preliminary road test. One thing I noticed, and my 79 yr. old father really noticed, was the gas pedal was very stiff. I have already replaced the plastic bushings in the pedal cluster with the brass rebuild kit. Tonight, I disconnected the throttle cable from the throttle body and confirmed the cable / pedal was not the issue. It seems that the supplemental spring on the throttle body is the culprit. Is there a different, easier spring that I can install or is a stiff gas pedal just part of the normal Porsche engineering? Or, should I look for a '73 throttle body without the supplemental spring? Thanks - Scott Make sure that the pedal board is not interfering with the pedal action, move the board as far right as you can. Not the pedal board... either the spring is the problem or the butterfly/axle itself. |
okieflyr |
Dec 5 2010, 08:55 PM
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#4
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9fauxteen Group: Members Posts: 816 Joined: 9-January 05 From: Phila PA Member No.: 3,426 Region Association: North East States |
Just started driving my "project" ('73 2.0L with 74' F.I. setup) up and down the block for my preliminary road test. One thing I noticed, and my 79 yr. old father really noticed, was the gas pedal was very stiff. I have already replaced the plastic bushings in the pedal cluster with the brass rebuild kit. Tonight, I disconnected the throttle cable from the throttle body and confirmed the cable / pedal was not the issue. It seems that the supplemental spring on the throttle body is the culprit. Is there a different, easier spring that I can install or is a stiff gas pedal just part of the normal Porsche engineering? Or, should I look for a '73 throttle body without the supplemental spring? Thanks - Scott Make sure that the pedal board is not interfering with the pedal action, move the board as far right as you can. Not the pedal board... either the spring is the problem or the butterfly/axle itself. I've got a spare 75 1.8 supplemental spring that you can have to use or compare. Is it still stiff without it? If the car has been sitting for a long time, the throttle body butterfly may have some corrosion or buildup on it that is dragging. Kevin |
Mikey914 |
Dec 5 2010, 09:21 PM
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#5
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The rubber man Group: Members Posts: 12,711 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
There is a steel piano hinge in the OEM pedal that could have rusted. Try working it back and forth for 5-10 min. You may just be able to achieve an acceptable level of resistance than way.
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sfrenck |
Dec 6 2010, 07:40 AM
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#6
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Not anything to do with the pedal cluster... action is fine when the throttle cable is disconnected from the throttle body @ the throttle body.
Anyone know if there is an "easier" spring? Kevin.... hold onto that 1.8L spring for me. |
benalishhero |
Dec 6 2010, 10:30 AM
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#7
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Member Group: Members Posts: 313 Joined: 28-November 07 From: Portland, Maine Member No.: 8,384 Region Association: North East States |
When you move the TB, with the cable disconnected, does it feel smooth?
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sfrenck |
Dec 6 2010, 01:25 PM
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#8
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
TB movement is smooth with and without the cable attached (and I cleaned the TB while it was out of the car to make sure the flapper didn't "stick").
Is a stiff pedal normal? How does the 914 pedal pressure compare to a modern car? |
Drums66 |
Dec 6 2010, 04:55 PM
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#9
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914 Rudiments Group: Members Posts: 5,321 Joined: 15-January 03 From: Coronado,Cali Member No.: 151 Region Association: Southwest Region |
...Sometimes the bushing's in the TB
wear out? (IMG:style_emoticons/default/idea.gif) (IMG:style_emoticons/default/bye1.gif) (repair or replace) |
pete000 |
Dec 6 2010, 05:05 PM
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#10
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Senior Member Group: Members Posts: 1,885 Joined: 23-August 10 From: Bradenton Florida Member No.: 12,094 Region Association: South East States |
I am in this same boat. I am replacing the cable, and the pedal it self to see if that helps. Not sure why the throttle feels so darn stiff compared to other cars.
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SLITS |
Dec 6 2010, 06:44 PM
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#11
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Most any FLAPS will have throttle return springs. They are a spring with a long attachment wire you can cut it for any desired tension.
It ain't a special "Porsche" spring, so it doesn't cost $100. I think about $3.00 is the going price. |
sfrenck |
Dec 6 2010, 07:20 PM
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#12
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Just to make sure that I'm asking about what everyone is answering about... I'm talking about #4 "supplemental spring" in the pic below.
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okieflyr |
Dec 6 2010, 07:53 PM
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#13
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9fauxteen Group: Members Posts: 816 Joined: 9-January 05 From: Phila PA Member No.: 3,426 Region Association: North East States |
If the the throttle body is lubed and smooth as well as the spring, I'd look back to the throttle pedal linkage. Is it possible that it may be getting into a bind when there is a LOAD on the cable? Can you get someone to apply tension or an independant springload on the cable? Can you vouch for the condition of the cable and it's lube? Ain't much, but it's all I got.....
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SLITS |
Dec 6 2010, 09:01 PM
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#14
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
The spring you are showing was not called the "supplemental" spring. It was the spring on the TB that Porsche initially installed, primary return spring.
The "supplemental" spring was installed from the TB arm to the rear of of the engine tin in case the primary spring broke, allowing for a wide open throttle condition. That's how I understood it anyway. |
sfrenck |
Dec 6 2010, 09:40 PM
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#15
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Well, I poached this image from PP and they list #4 as the Supplemental Spring (added after the '73 TB which had only a straight arm and no coil spring (www.914world.com/bbs2/index.php?showtopic=108520)).
No matter the name, (IMG:style_emoticons/default/agree.gif) that spring does what you say Ron. Still have the fundamental questions: is the 914 pedal action much stiffer than modern day cars and/or does anyone know of an "easier" #4 spring? |
SLITS |
Dec 6 2010, 09:52 PM
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#16
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Probably a bit stiffer than modern day cars, but the problem is somewhere. I've had stiff ones and really light ones and I can't tell you why. Cleaned TBs, checked angles and rodded out cable tubes.
I can't remember if you rebushed the pedal assembly, but if worn, putting a load on the linkage could cause binding. If not loaded, it would move free and easy. |
championgt1 |
Dec 6 2010, 10:14 PM
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#17
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Don't embarrass me Filmore! Group: Members Posts: 2,680 Joined: 3-January 07 From: Tacoma, Washington Member No.: 7,420 Region Association: Pacific Northwest |
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TheCabinetmaker |
Dec 7 2010, 06:27 AM
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#18
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I drive my car everyday Group: Members Posts: 8,309 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
Isn't it amazing that most everyone misread you first post? The pedal cluster is NOT the prob. I've seen the same prob with many late model cars. Get a throttle body from a 73.
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Gint |
Dec 7 2010, 06:41 AM
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#19
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Mike Ginter Group: Admin Posts: 16,093 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains |
Just because the cable moves freely when disconnected and testing by feel with your hands doesn't mean the cable is ok. They can (and do) wear on the inside and not be affected unless there is tension (as there is when it's installed) on the cable. I've seen just the very slightest bend in the threaded end of the cable cause serious binding with the cable installed and under tension but not when testing by hand and unconnected.
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sfrenck |
Dec 7 2010, 01:55 PM
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#20
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Member Group: Members Posts: 492 Joined: 28-February 10 From: Wilmington, DE Member No.: 11,411 Region Association: MidAtlantic Region |
Well, I do have a spare throttle cable to replace the one I have. Looks like I have a new project for tomorrow afternoon.
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