Bis accelerator cable problem

[Da Londo]

I replaced the accelerator cable on the Bis with a new one and I've got a problem now.
 We adjusted the cable at the pedal which is also been replaced and everything seemed ok.
However, once the car gets to running temperature the pedal will not travel smoothly nor return to idle position leading us
to think the cable expanded inside the sleeve. We then adjusted the cable with the car nice and warm which helped a bit
but the problem still persists. Is there anything you can do wrong in fitting the cable?

[Pete126]

There should be know sharp bends in the cable, I had a similar problem which turn out to be a rusty accelerator shaft as it passes through the tube thats fixed to the floor under the carpet. you can try using a light oil on the ends But Don't use WD40 or Plus Gas they swell the plastic/nylon bushes and makes it worse

[Da Londo]

Tnx, but the is LHD and the cable runs trough the centre where the choke cable runs, so no tube. 

[Pete126]

You have a bracket on the floor where the acc'' shaft runs through, on the RHD the bracket is longer, check its not sticking

[Da Londo]

This is new and working perfect, it really seems to be the cable.

[drcdb15]

Check that the clamp (cable nipple) which holds the cable in the operating lever at the carburettor end is free to rotate as the cable is moved back and forward. This cable is NOT a Bowden type (flexible, multi-stranded), it is a rigid single core cable (so it can transmit compressive load - being pushed - as well as tensile load - being pulled). If it is not free to pivot at the engine end it will jam - watch it operate as a helper presses the pedal and you will see the cable moves through an angle of about 90 degrees from one end of its travel to the other, relative to the operating arm. Unless this pivot point is free to move, pressing the accelerator pedal will force it to one end of its travel, where it will remain jammed when the pedal is released. Adjust the nipple set up using shim washers so the the grub screw presses on the cable ONLY, so as to grip it, without also pressing against the operating arm (thereby locking the cable to the arm and preventing it from pivoting freely).

If you have the original Fiat washers, you will find a groove in one side which intuitively you may think is where the cable is supposed to lie. That's the idea, but in my experience these washers get mis-positioned over the years, and simply assembling any old how with the cable in this groove is not in itself sufficient to ensure correct operation - you must ensure also the washer is in the correct position relative to the operating arm.

Depending on what exactly you have on your car, you may be able to drill a 2mm hole through the nipple pin and use a split pin with washer to secure the nipple to the operating arm, whilst using the grub screw to clamp the nipple to the cable.
 

[Da Londo]

Nice one! Will check and see.

[Da Londo]

Okay, this actually would have been helpful if it was a problem with the choke cable. Accelerator works different.

[poxxxy]

Right... do you have a bracket which the cable sits in near the carb end? My bis was missing this so I had to fabricate something from steel wire to keep the outer of the cable held back... hard to explain... but without this in place I found that the throttle cable kept sticking.

[drcdb15]

Okay, this actually would have been helpful if it was a problem with the choke cable. Accelerator works different.

Well, different construction on the Bis, true, but the same principle. If you are a subscriber to the Forum you can find the original Fiat workshop manual diagrams showing how to set up the carburettor cables on page 54 and onwards in the Bis/water-cooled workshop manual.

If your cable is free-moving within the outer cable when both ends are disconnected, then either there is a problem with the linkage at one (or both!) ends not being fully free to pivot, OR when the cable is put under tension, it is being pulled into some bend or kink or other constriction that is squeezing the outer cable onto the inner cable and making it stick.

Do you have all the correct cable supports (there's one on the a/c gearbox for the clutch cable, for example, I don't know about the carb cables on the Bis) in place? As Poxxxy has found, unfortunately with inept tinkering over the years these cars do sometimes suffer from small but critical parts being missed off, broken or distorted during reassembly.