1985 c10 dual capacity pump system

[bob seifert]

Ok this is installed on 85 and 86 c10's. must be a need. Ive seen it posted that disconnect it and every thing is fine. Then why is a extra shot needed between idle and part throttle. but if you discount it it fine.That's crap. It wasn't put there for fun. The quadrajet was designed for economy and performance. If i disable the dual capacity pump at anything above 170 degrees i still get a double shot. what if i hook up a switch where it gets power till it warms up and then switch it off, to disable it. Then i can leave to go to work without having to feather the throttle till it warms up.

 

[Charlie]

 

[1987 GMC Jimmy]

It shouldn’t need that much coaxing on a cold start even with the single shot. I would look into this further. Unplugged, it should run pretty ordinarily and not have to be coaxed. I’ve heard of the accelerator pump being wired to a toggle switch, but I’ve never seen it done on here that I can recall. Is the temp switch a discontinued part that you know of, or can you just adapt a TBI style temp sensor? Someone asked this a while back, and I don’t think any results came of it.

 

[highdesertrange]

I have no idea what you guys are talking about. a toggle switch on a accelerator pump? highdesertranger

 

[ArCanSawDave]

I have no idea what you guys are talking about. a toggle switch on a accelerator pump? highdesertranger

Some quadrajet carburetors were equipped with a dual capacity accelerator pump. There is a solenoid in the air horn, when activated the solenoid decreases the capacity of the accelerator pump shot. The solenoid is grounded when a thermostatic switch closes based on coolant temperature. AFAIK, when the solenoid is disconnected the carburetor behaves just like a standard quadrajet.