I have a 84 cj7 with an MC 2100 that has been on there for a few years now. It has run just fine in the past, but now when I idle along in first gear it lopes really bad. When I accelerate a little it stops. I will then take my foot off the pedal, it slowly gets worse and worse finally to the point i have to push the clutch in.
I have tried to adjust this out in the carb(probably doing it wrong) on the idle screws nothing seems to make a difference. I have checked the timing it looks good.
Check for air leaks. Spray carburetor fluid at the base of carb when its running and see if it raises the carburetor idle. Rebuilding would be agreed but try that too!
I am just now getting to work on this after all this time and for some reason I couldn't get back in here on the forum!
Anyway i took the carb cover off and spray some cleaner in there hoping it was just something caught because it has sat so long. i also put new plugs in and fired it up and it ran good for a minute or two then started running crappy again. when i pulled the plugs they were black as they could be and it the exhaust was smoking pretty bad black.
So I am going to get the carb kit and rebuild it next. I have good fuel pressure and the filter has been replaced as well.
If it sat for a long time, do an engine flush before you put the NEW carb in; add ATF right now to your oil and run it for an hour or so.
Do not REV it at all. Just let it get hot. Let it sit overnight, run it for 30 minutes or so and DRAIN it. Change to good oil, filter and get the carb rebuilt.
If the plugs are new, spray them with carb cleaner and use a soft toothbrush to clean them up again. Did you ever check the timing?
ok got all that done put the rebuilt carb back in and now no fire to 2345 only 1 and 6. Cleaned plugs put new cap rotor and wires on, wire are really old. I can't get it to start.It ran earlier and i check the timing it was a little off was trying to set it but with the miss couldn't get it set.
I thought maybe i have a vac leak check all hoses and soaked the carb base and the intake mani got nothing out of that. Only thing that hasn't been touched is the coil.
I am getting plenty of gas.
I check plugs when it was running by pulling each one while it was running.
ok got all that done put the rebuilt carb back in and now no fire to 2345 only 1 and 6. Cleaned plugs put new cap rotor and wires on, wire are really old. I can't get it to start.It ran earlier and i check the timing it was a little off was trying to set it but with the miss couldn't get it set.
I thought maybe i have a vac leak check all hoses and soaked the carb base and the intake mani got nothing out of that. Only thing that hasn't been touched is the coil.
I am getting plenty of gas.
I check plugs when it was running by pulling each one while it was running.
Are the wires securely pushed in all the way? Sounds like some may not be seated well enough. Double check the coil plug at both points.
Only other thing that comes to mind is the timing is off. Turn the distributor a bit and try starting it. Find the sweet spot and fine-tune from there.
Did you do the Team Rush upgrade? Or is it stock, other than the carb?
Thinking, if you plan on doing the Team Rush down the line, get the MSD 8205 coil. That's the recommended one for a direct fit. It's what I run and it's been great!
Before condemning the carburetor, make sure the ignition works well. Spark plugs should be clean and gapped properly. The spark plug wires, conventional coil, cap and rotor must be in good shape. Be sure the distributor advance mechanisms function properly.
Spark wires and the coil can be readily tested for ohms resistance readings. If these components test okay, the other devices associated with ignition performance include 1) the ignition module (a common source of trouble on Motorcraft ignitions), 2) the MCU (microcomputer unit) and 3) an array of emission control devices with solenoids and vacuum switches.
You can check the distributor advance unit performance with a conventional timing light and a common hand vacuum pump. With the vacuum advance hose disconnected and taped, hold the timing light on the timing mark while increasing the engine speed. The centrifugal spark advance unit should show a steady timing advance to 2000 crankshaft rpm. (Stay safely away from the engine’s fan and do not exceed 2000 rpm during this test.)
To test the vacuum advance, turn the engine off and disconnect the three-wire connector at the 4- and 10-in/hg switches on CEC systems. (See the underhood emission decal for CEC information.) Hook a hand vacuum pump to the vacuum canister on the distributor. With the engine at an idle, apply vacuum to the canister. There should be smooth timing advance at the marks on the crankshaft damper and a noticeable increase in engine speed as you increase the vacuum supply. The vacuum should hold steadily if the diaphragm is in good condition.
I am trying to remember but it has been too long ago when i installed the 2100 but was there something about plugging a hole in the bottom of the carb? for some reason i have JB weld in there? :laugh2:
Also i don't have the nutter bypass done would that be something i should do?
Yes! If you are running a 2100, the nutter bypass is a must. Otherwise, the computer will try and correct the idle but end up making it worse. The computer relies on the feedback from the carb to let it know what it's supposed to be doing.
Ok so i have looked this up and just want to make sure i do it right. Seems simple but some explanations are not saying it the same way.
Basically at the distributor cut those wires splice in the two new wires and then go over to the ECM find the same two wires cut them and splice the two new wires in there leaving two old sets of wires with nothing attached?
I think you need to cut the Orange and purple wire from the distributor, then twist the replacement wires and tie the new wires into the wires from the ignition unit. I dont think you can just splice into them. I think you need to ADD the new one. the image below shows what I am trying to say... See where the purple wire is not disconnected on the right side?
New wires go into the orange and purple off the distributor to the same wires off the ECM?
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Jeep Enthusiast Forums
18.5M posts
726.8K members
Since 2000
A forum community dedicated to all jeep owners and enthusiasts. Come join the discussion about performance, engine swaps, modifications, classifieds, troubleshooting, maintenance, and more!