Throttle sensitivity

[Formula413]

I'm just wondering if anyone else has a vehicle with an overly sensitive throttle and if there is anything that can be done to improve it. My car is a '97 Ford Escort wagon. I find that the throttle is very jumpy, it is hard to make small throttle inputs such as driving around a parking lot or trying to add a small amount of throttle when going downhill. I feel I could squeeze out a little more fuel economy if I could more easily make very small throttle inputs. I have heard of people adding a hand throttle but i don't want anything that extreme. I'm pretty sure you are not supposed to lubricate a throttle cable. Could I possibly change the return spring on the throttle body? I may also try removing the throttle body and cleaning it just in case there is any gunk in there exacerbating the problem. Anyone have any thoughts?

[igo]

Check and see if there is gunk on the back of the throttle body plate (if there is gunk clean it off). The cables might be sticky too.

[JohnnyGrey]

You can change where the cable attaches to the pedal. You can gain sensitivity by increasing the travel of the gas pedal. Perhaps you could also get a cam for the throttle body. My porsche has a cam, so it works like a nautilus machine or a compound bow. More pedal travel is dedicated to the lower throttle regions (this is important on a manual V8), and once you start going past a certain point, the car throws you back into your seat. The idea is, you don't need the kind of resolution at full throttle that you do near idle.

[Peter7307]

Have a look too at the engine end of the cable. Some are adjustable to reduce / increase throttle sensitivity. By the way the car makers put them there to give the impression of more power.

You can lubricate the throttle cable but check the handbook and see what is recommended as the lubricant.

Check the pedal pivots too. These can build up and stick causing a stiff and jerky throttle.

Pete.

[JohnnyGrey]

Also don't discount a misbehaving IAC valve. Try unplugging it temporarily and see if things improve.

[Formula413]

Originally Posted by JohnnyGrey

My porsche has a cam, so it works like a nautilus machine or a compound bow. More pedal travel is dedicated to the lower throttle regions (this is important on a manual V8), and once you start going past a certain point, the car throws you back into your seat. The idea is, you don't need the kind of resolution at full throttle that you do near idle.

This is the right idea, I want more control at light throttle. I don't know if that would be feasible though. What kind of Porsche BTW?

After playing around with everything it seems like the stickiness I am feeling is in the pivot for the pedal itself. The throttle blade seems to have a nice snap to it with no stickiness.

Here's a few pics of the TB for reference. The black plastic piece attached to the cam is the cruise control cable.

[JohnnyGrey]

This is the right idea, I want more control at light throttle. I don't know if that would be feasible though. What kind of Porsche BTW?

It's a 928. I'd look into a new throttle cable. They are wear items. A new one might surprise you.

[igo]

Here is one idea. Take off your throttle body and dremel the throttle plate to a knife edge. I did this on my pervious car and it seemed to make the pedal more responsive but, you can screw up your car if you take off too much material.

[Formula413]

Originally Posted by igo

Here is one idea. Take off your throttle body and dremel the throttle plate to a knife edge. I did this on my pervious car and it seemed to make the pedal more responsive but, you can screw up your car if you take off too much material.

This idea is actually widely used as a performance mod on sports cars, it is often referred to as "porting" the throttle body. It involves doing what you just mentioned, as well as removing as much excess material from the inside of the TB as possible, including even some of the shaft, partially covering any holes for vent lines, IAC valve etc etc. This is done largely to increase throttle response as you mentioned. However, as odd as it may sound, decreased throttle response is really my goal.

[slopemeno]

Increasing the finess of the throttle is a great idea. I went the other way with a '72 Chevelle I used to have, but for economy it's a great idea.