hey i have a rochester quadrajet, when i got my car there was some weird stuff done with the wiring under the hood..what is the grey plug on the top front right side of my carb? it has 2 blue wires coming off the side, and a white plug goes into it with 2 orange wires, that go into a cluster of wires. the 2 blue ones are cut and capped off..what do they go to? im trying to get this thing back to normal, thanks

 

Mixture control solenoid.

 

Thanks....do you know if it matters if i use one with a blue or a grey plug? mine has the grey plug right now, but a carb. rebuild guy told me that i should just get a whole new one and skip the rebuild, because he said he has never seen one with 4 wires on the solenoid, and hes not sure where the 2 blue wires are supposed to hook up. he told me that it probably isn't the original carb for my car and that it might have come off a truck. and that instead of wasting my money trying to fix the things wrong with this one i should get a remanned one, because those blue "mystery wires" are probably throwing my computer off and making me run like **** I found some on ebay for 305$ free shipping but they all have blue plugs....mines grey...

 

Your friend may have given you the right advice. On truck carbs they used a similar plug but it's grey and shaped a little different becuase it's not a mixture control solenoid- it's a "dual capacity accelerator pump" solenoid. Totally different function from a MC Solenoid.

A picture would help confirm this.

 

I'll try and get a picture up after work today, if it is what you think, then the one with the blue plug would be a mixture control solenoid and should work on my car??

 

Yes. You might have to determine if they just hooked the original MC solenoid wires up to the white plug (which wouldn't work properly) or if they tried to rig up fresh wires to run the dual accelerator pump solenoid (which who knows how successful they might or might not be with that).

Also, if it's a truck carb (no MC solenoid) then it also won't have a Throttle Position Sensor on the driver's side/front of the carb.

In any case, this thing's gotta be throwing a check engine light, right?

 

it's weird, the carb has been on my car since i got it, it didnt have any light on at all for a long time, then when it finally did a few months down the road i accidently broke it somehow and now i cant read any codes and its always stuck on. I confirmed with a carb. vender that it is actually a truck carb and the extra wires were for CA emissions, and that the carb for my car will have a blue plug....not a grey one. I cant figure out how to upload pics yet, but i would like to find out, so i can take a picture and show you what it looks like. one of the guys i know has built carbs for about 20 years and he said he has never seen one with that,.