How can you tell if you are getting full throttle or not in an '83sc?

Thanks

 

You could probably watch at the throttle plate as an assistant floors the pedal, then pop off one of the linkage ball connections and work the throttle plate by hand. I need to do this as well, Im not sure if that is the best way, but Im sure it would work.

 

Thanks Ryan, I am just wondering if that tinkle of play in the pedal maybe means I am not getting full throttle, I will try what you suggest.

Simon.

 

I was not getting full throttle on my 88 Carrera and found there was no more adjustment on the cable at either end. I obtained a one and a half inch threaded spacer and inserted it in line with the treaded portion of the existing cable. I had a friend actuate the accelerator by pushing it all the way to the floor while I checked position of the throttle body. I readjusted the linkage and had full throttle again. It now accelerates much better on the top end. The piece I found is about a 1/4 inch in diameter and heagon shaped with a femalwe and male end (metric). I just inserted in between the rod end that snaps onto the accelerator pedal and the cable. I found it at a VW supply shop here in San Antonio.

 

Simon: Have another person hold the pedal at full throttle while you are at the engine. Watch how the linkage moves at the left side of the throttle body. Have your helper "pump" the pedal a couple of times so that you understand what you're looking at. Then have your helper once again floor the throttle and hold it. If you can move the linkage further in the direction of full throttle you will need a repair. DO NOT attempt to adjust the linkage - if it was right once it can't go out of adjustment. The first thing that we have to get out of the way is to check the pedal rod at the back of the gas pedal. You have no idea how many times I've found that the press on end of that rod has been dislodged by a vacuum cleaner, mat removal, etc. If the rod is not connected, locate the hole it presses into on the back side of the pedal - problem fixed! Now, the real problems... Possible problems, in order of most common to rare are:
1. Vibration damper failure - locate the vibration damper (it's about an inch and a half long, an inch in diameter, and was gold colored originally) located on the rod that comes out of the firewall at the nose of the transmission, before the ball cup at the trans bell crank (throttle lever). Pull on the rod at each end of the damper and check for play, which indicates that the rubber damper inside the housing has broken. Repair requires replacement of the damper.
2. If the damper is OK, check the bell crank bushings on the bell crank a few inches from the damper. The center tube of the bell crank has a bushing at each end, and must ride smoothly on the metal post that screws into the side of the trans. Grip each end of the bell crank shaft, in turn, and wiggle it. It will be obvious if the bushings have failed, the shaft will have considerable movement at one or both ends. Repair requires new bushings.
3. If you still haven't found the culprit causing the play you're not going to like this! Inside the engine compartment, the rod that you were watching connects to another throttle lever (bell crank) that mounts on the top of the crankcase, under cylinder # 3 intake runner. Yes, it's hard to see. If you can't verify the condition of its bushings you must remove your heater blower and look again. This bell crank is construted differently than the one on the trans. Rather than a tube with internal bushings this one is a rod with external bushings, which ride in ears that are part of the removable casting that holds the bell crank. If these bushings have failed, like the other one, there will be significant (a mm or more) play at one or both ends. Repair requires lots of experience working with linkage - if you find failed bushings and want to tackle this let me know, I'll try to guide you through it.
4. If the linkage is all good you have one more place to go. The pedal cluster. Remove the pedal board and examine the throttle lever at the tunnel side of the cluster. The rod that presses onto the pedal attaches to the lever. Again, smooth movement with no play is acceptable. This lever is a rod that fits into a tube, the bushings are at each end of the tube, and inside it. Repair by removing the lever and installing new bushings. This is not easy and you need good lighting.

Let me know what you find!
Pete

 

Problem solved. Turns out the the pedal rod ball linkage was not inserted into the little hole in the back of the pedal. I was losing a significant amount of travel/throttle as a result because the push rod had seated itself at the bottom of the gas pedal.

Many thanks Pete and everyone else for your valued input, much appreciated.

Simon.

 

Good news! A happy Porsche is a Porsche at full throttle!
Pete