Odd Choke Coil Failure- 1970 Q-Jet

[Mark E.]

I took my 1970 coupe out for a pleasure drive this holiday weekend. It ran perfectly, including an instantaneous cold start with a fast idle that would pass PV. But after 20 minutes of driving, it began idling at 1,200 RPM and loaded up when idling. When I removed the air cleaner I saw the choke coil rod jammed between the choke stove and carburetor's choke linkage. The photo on the left shows the scene after I removed the stove and rod. You can see the shape of the last inch of the coil is distorted and its rod end link is at 10 o'clock.

Any ideas how or why this happened? In normal operation the rod link at the end of the coil operates between 4 o'clock (cold/closed choke; see photo of a good coil on right) and 1 o'clock (hot/open choke).

I replaced the coil and all is well again.

Note that 1970-72 LS5 (and maybe some other models?) locates the mounting screw for the choke coil's base on the backside (between the coil's base and the intake plenum). I mention this because most cars I've seen with this type of choke coil mount the screw on the outside (facing the cylinder head), like the one shown in the second and third photos (not of my car). I happened to have an extra good coil with an outside hole, so I transferred the good coil from that base to the one on my car. The coil is pressed on the base then soldered on one end. Careful tapping broke the solder joint and allowed the coil to be gently pried from its base. I used JB Weld in lieu of solder to secure the new coil to the car's original base.

So be mindful which configuration you're getting when replacing a choke coil.


20230528_104051.jpg Choke Coil.jpg divorced-choke-1059874.jpg