Disconnected Decel valve on '74 2.7 CIS
 

My '74 with 2.7CIS will not idle correctly when the decel valve is hooked up (item #15 on the below diagram). When I have the decel valve connected, the car hunts for idle and stalls every time I drive the car (upon deceleration) and idles too slow to maintain and stalls out. When I disconnect the decel valve, the car idles at 1000rpm, but backfires from the exhaust and has a pronounced "miss" at all rpms. I'm going through a methodical troubleshooting process, but I wanted to know if anyone else has seen a similar scenario with their decel valve. Thanks!



http://forums.pelicanparts.com/uploa...1155313329.jpg

they're adjustable you know.

John,
I didn't know that. How would I go about adjusting it? Thanks!!

I think I found the adjustment described in an old post...

leon
I found out that the decel valve is adjustable. You can adjust how long the valve holds the engine at high RPM after deceleration. On top of the valve there is the threaded vacuum nipple and a locknut. By loosening the locknut you can screw the nipple in, or out of the decel valve. By going in, you lower the amount of hold time, and the hold RPM. By screwing it out the hold time is longer and hold RPM is higher. Then re-tighten the locknut. I couldn't find this in the factory manuals, but I don't have a complete set. I just tried it.

[This message has been edited by leon (edited 08-05-2000).]