Re: RUN AWAY 55 400!

Posted by HH56 On 2023/12/5 18:00:38

It does sound like the linkage return spring might have broken or become disconnected and is not returning the linkage to the idle position. The spring could be in one of two places or, in some cars, both places.

Originally a single spring was positioned under the floor board pulling on the pivot mechanism at the bottom end where the accelerator pedal pushes a rod thru to the pivot piece. Later another location was used in the engine compartment where the spring was mounted vertically, one end on a piece of linkage on the firewall at the rear of the engine and the other end thru a hole in the welded flange toward the bottom of the firewall where pieces of sheetmetal are joined. In some cases a spring was added so both places were used.

Another possibility is since you have the GM transmission, instead of a rod for throttle linkage the GM trans uses a flex cable connected to the accelerator linkage to work the throttle and kickdown mechanism inside the transmission. It is also possible something has happened to the cable or whatever piece was fabricated to attach its end to the accelerator linkage and cable is somehow binding and not letting the accelerator linkage return to the idle position. Depending on how the cable was attached, positioned, or clamped, make sure it did not kink or get damaged by being too close to a hot manifold.