Rough Idleing.. stumped mechanic
The jeep has had ongoing erratic idling issue for a couple of years.
It has an aftermarket carburetor on it that was put on by a previous mechanic 3 or 4 years ago upon that mechanics recommendation.
At any rate, I found this mechanic in town and he works on a lot of jeeps and said he could get it running right. He said he's worked on hundreds of jeeps. He's never encountered one he couldn't get running right until he met mine… He’s given up on it and now it’s in my hands.
So here's what has been done:
Replaced Exhaust Manifold (he said this was the cause of it)
Checked Plugs and wires.
Replaced Catalytic Converter
He says he's tested a lot of the basic parts too, but he's stumped.
Basically... most of the time when I brought it back to him, he would clean up the carburetor , adjust the idling screws and give it back to me. Sometimes, he would open the idle up a little bit more to try to blow any dust/dirt out... but it would continue to idle rough as the dirt wouldn't clear out and he'd have to clean the carburetor again. The idleing is so bad that it stalls out. Every time the carburetor gets cleaned, it seems to run fine for a little while and it progressively gets rougher until it's stalling out.
I did ask him when I picked it back up today if he thought there could be dirt or gunk in gas tank that is causing the problem and he said there is no major deposit build up that would lead him to believe that was the case. I've also asked him if it could be the power distributor cap and he doesn't think it is that.
I am going to start back at square one and see if I can get it going right. What are your guys' thoughts? Where should I start? Unforutantely, I have a small one car garage, but I can be pretty resourceful to try to get things done.
Any direction (websites with how to's?) on how to clean the carburetor would be helpful too. Mechanic said I just need to take off the top of it and clean that part, then reattach.
Blindly converting to FI is illogical.
There are many things that can cause a rough idle.
From your post, it is not clear what this mechanic already checked and ruled out. So you need to start with the basics.
Who will be troubleshooting this going forward? If you, then check and rule out one item at a time until the problem is resolved or the problem is plainly clear. If a new shop, then clear communication is key because, to make money, the shop will be incented to rush to a conclusion and throw parts at the problem.
I am somewhat confused why the original person decided that a cracked exhaust manifold or clogged cat would cause a rough idle. A cracked exhaust manifold just makes noise, unless it couses a cylinder to go lean and burn a valve. A bad valve is easy to diagnose. Similarly, a clogged cat does not cause a rough idle - but it might make it impossible to run at highway speed. If you did not have these symptoms as well, I wonder if you got bent over.
You will need to check all the basics. For example, you might have a vacuum leak - a hose or the intake manifold, that sort of thing.
Your statement that the carb constantly needs to be cleaned must be better understood. Have you installed a quality, low-micron fuel filter before the carb? If there is dirt coming thru, that would prove it before you took the trouble to drop the tank.
At this point in the process there will be more questions than answers. Troubleshooting is a logical process of testing and ruling out. Let us know more about what you have, what you absolutely know, what you are not sure about, and who will be doing the work.
What carb is on it now?
Hey Guys, Thanks for the feedback. I think I still have a good enough relationship with the mechanic to get a better understanding of what's been done and what hasn't. Being a novice, a may have mis-stated some of the things, but I will call him to clarify and provide more detail to eliminate any run around. I can tell you I will be the one working on it. Once I get to talk with him, I will report back.
Sounds more than vaguely familiar. Stumbling and stalling could be due to a bad cap, rotor, dying ICM, half botched nutter bypass, vacuum leak. Tons of things outside the carb can be causing crappy idling and dying out. Trust me - been there, replaced that, now running Forest - Forest Gump.
I figured it out. There are two idling screws on the front of the carburetor. The springs on these screws weren't providing any tension. They were just sitting on the screw, but the screw was turned out so much that the spring wasn't pushing against the carburetor or the screw head to keep the screw in place. I replaced these springs with longer springs that I got from my local hardware store and cut down to size to fit the spacing I needed. and the jeep has been running without this issue for a couple of months now. These screws must have been rotating due to engine vibration... and have gotten out of sync.
When I was researching this problem, I also came across this website, which I thought was pretty well put together:
The carburetor that is on it is the same one as what is in that website - Carter BBD
Thanks for all the input from the community! Hope this problem helps others.
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