When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
From: At my Bar drinking and wrenching in Lafayette Colorado
The first photo is the Transmission Controlled Spark solenoid. It prevents the distributor vacuum advance from functioning until the tranny is in 3rd gear. This keeps the timing retarded at lower vehicle speeds (like in stop-n-go traffic) for lower emissions. The second photo is the idle solenoid. Depending on the year and application, some vehicles used these to keep the idle speed constant when the A/C compressor kicked on. Other years used these as an anti-dieseling solenoid by closing the throttle blades when the engine was shut off, thus preventing engine run-on after shutdown.
