Hi, I had a quick question I was hoping someone could help me with. I just got finished rebuilding my first carburetor (carter bbd) today!..a few rough spots but overall not as intimidating as I initially thought.. I just hope it works when I hook it up tomorrow!! I was just curious if there is a way to tell if the stepper motor has gone bad. The manual didn't seem to touch on it very much and just said to put it back in but if I am going to the effort of rebuilding this I wanted to make sure everything is in working order. I noticed it had some pretty heavy carbon build up and it doesn't seem to want to move (not really sure if it is even suppose to lol) Is there any way to test this component of the Carter BBD carburetor?
There is. If you google Jeep Adventures under the hood and then go to the stepper motor link he'll show you the sequence to apply power to test it. It should move in and out without forcing it.
Basically, when the car is started, the motor should move the pins all the way into the carb and then back them out to their halfway position. This is called the initialization step. It's in the TSM. If it does that you should be set. If you still had issues I would look to the o2 sensor or wiring. During warmup the pins should stay still at a preset place. Once warm, the computer goes closed loop and the pins will cycle in and out based on the signal from the o2 sensor. There are a few temp sensors that need to work (one in front side of intake and one in air cleaner) to tell the computer to enter closed loop. That under the hood site explains all of this. However I have to actually crank my Eagle to get it to initialize. On jeeps you can turn the key to run to see it. It happens quick so have someone else start it while you watch the stepper pins. On later Eagles like after 83-84, the distributor needs to generate a tach signal at cranking RPMs for the computer to wake up.
Hope that helps!
Thank you dude Mac! You have been a great help! Hope you have a wonderful weekend! I will let you all know how it starts up tomorrow...I was having awful problems before. Rough idle, stalling, etc. It even died going up a steep mountain road covered in ice!! I hope this fixes it!!
You bet! If it's shot you can get a new one for about $35.