Carb tunable?

[WesB]

I recently bought an 84 BII and this thing runs rich. Are these carbs tunable even with the computer or does the computer do the tuning? Thanks in advance
Wes

 

[martin]

There's a mixture control solenoid on the back of the carb that is controlled by the computer. If there's an issue with the solenoid or if the computer is not controlliing it for some reason of another it defaults to rich. There is a base idle mixture control at the front of the carb that is usually capped off but only affects things at and just above idle. These carbs are sensative to float level and it's not uncommon to find a float that is punctured which causes a major rich or flooding problem. I solved the problem on mine by making a manual metering block to replace the solenoid. It also made things easier when I eventually ripped out the computer and installed a hybrid ignition system. Hope that is of some help.

 

[Hotrodlincoln]

It can be tuned with a manual metering block or by changing the jets in the carb. 14 mpg doesn't seem all that bad though. I could only manage to get 17 out of my old ranger. My 85 will get about 17-19 depending, but that's all highway. Gets about 12-14 in town. Although I did just put a set of used 31s on it, so that might go down.

 

[WesB]

So what you're saying is that in its current state, the carb is not tubable and I need to take off the solenoid and put on a manual metering block. Are there any write ups on how to do it. I'm not very familiar with carb'd vehicles (I like efi and this b2 will end up getting efi in the future).

 

[kimcrwbr1]

If you computer is working correctly and all the sensors are good you can try a new feedback solenoid and the carb can always be rebuilt the carb number should be on the flat plate in front of the choke. Have you run the codes and checked all the vacuum lines are good and connected in the proper places. The tech library will show you how to pull the codes under EEC-IV diagnostics. If you have to pass a visual inspection dont block off the feedback solenoid I would try and pass the codes unless you don`t have emissions then do the duraspark conversion and put a non feedback carb on it that is also in the tech library. Any Qs just ask but if you can adjust the mixture needles at the base of the carb the best way I have found is to get it running then unplug the idle motor and turn the needles out to get the highest rpm possible or highest vacuum reading then check them turn them in counting the turns in then back out they should be within 1/2 a turn if not the carb needs a rebuild or you have a vacuum leak somwhere. The best way to find a vacuum leak is with a piece of vacuum hose up to your ear and take the other end around all the gaskets and fittings and listen for a hissing noise especially around the carb base. I have talked to a couple guys now that were able to get the stock emission stuff working good but running rich is definately carb solenoid related does the solenoid click when you turn the engine off for a few seconds if not that could be your problem and is the O-2 sensor connected and the wire is not grounding if it is always showing lean the solenoid will stay shut causing a rich condition. Run the codes

 

[WesB]

Thanks alot for the information