Throttle body supplemental spring / stiff gas pedal Options

[sfrenck]

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]

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]

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]

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]

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.

[sfrenck]

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]

When you move the TB, with the cable disconnected, does it feel smooth?

[sfrenck]

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]

...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]

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.

[SLITS]

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]

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.

[okieflyr]

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.....

[SLITS]

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]

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]

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]

It should not be that stiff. Maybe a little stiffer than a new car. My 74 2.0 is very smooth.

[TheCabinetmaker]

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.

[Gint]

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.

[sfrenck]

Well, I do have a spare throttle cable to replace the one I have. Looks like I have a new project for tomorrow afternoon.