1981 CJ7 lack of power

Tiny
ZACHARYTRENT
  • MEMBER
  • 1981 JEEP CJ7
  • 4 CYL
  • 4WD
  • MANUAL
  • 56,000 MILES
1981 CJ7 151ci 4cyl Timed at 10° idles smoothly with no problems. As soon as I try to put it in gear and try to m move, it tries to stall and begins spitting and popping out of the carburetor. I have r replaced the entire ignition system, except the actual distributor. When I adjust timing, I do it according to the Haynes manual, which says to remove the vacuum advance line and block it. I time it to 10° and replace the vacuum line, the timing then automatically advances to around 30°, jeep then runs fine until it gets hot (usually when offroading). If I time it to 10° with vacuum line attached the jeep will idle fine but not move in gear, and spitting and popping starts again. Any ideas or suggestions would be helpful.
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Tuesday, February 22nd, 2011 AT 9:36 PM

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Tiny
CJ MEDEVAC
  • EXPERT
Plugging the line, while timing is correct.

Are you timing at the correct RPM?

What is your idle RPM?

If your harmonic balancer has "slipped" in the inner rubber (between the 2 metal parts), The Mark will not be an accurate, as to actual TDC.

Take your Ignition Module to have it tested (FREE at Autozone and Advance Auto, others too) Test it over and over 5-8 times (sorta warms it up), if it fails the last few, replace it. Regardless of what they say!

Before you walk out the door, test the new one the same way. Do Not Ask. That was the day I felt like suicide, I checked everything a hundred times, and it still, would not start. Who woulda thought the NEW ONE WAS BAD TOO?

Lets check the intake for tightness, carb to intake for tightness, and the carb screws themselves, that hold it together!

Check any and everything for vacuum leaks (if you do not know how, I'll tell you!)

This may also be a carb problem--do you know how to Tweak it?

I may be able to help with all of this. Mega detail really helps me, as well as history.

Go into CJ 5, 7, and Scrambler Forums, I have answered there a lot, and a lot of info there also, some may apply to you also. Even though you have a 4 cylinder.

For Sure, reply below and let me know whats been done thus far!

The Medic
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Tuesday, February 22nd, 2011 AT 11:09 PM
Tiny
CJ MEDEVAC
  • EXPERT
Can you tell if the centrifugal advance is working. Watching your timing mark while gradually increasing the throttle. Does the Mark advance, then settle back down to "Correct Timing" when you release the throttle. Do this with the Vacuum Advance Plugged off, as manual says.

From what you said about plugging the vacuum line back in, Vacuum Advance is working.

If you are having distributor problems and need to change distributors, I can talk you thru the EZ way, if you have not removed it. Or the "More Involved" way if you did snatch it out!

Really check good for vacuum leaks. They are often overlooked and cause mega problems.

Keep me informed

The Medic
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Wednesday, February 23rd, 2011 AT 4:21 PM
Tiny
ZACHARYTRENT
  • MEMBER
CJ Medevac,
Thanks for all of the suggestions. I will start working on the Jeep again this afternoon, and let you know what results I get. I believe I am timing the Jeep at approximately the correct idle speed, however it is difficult to tell because there is no Tachometer, that is soon to come. I have already found one vacuum line that was unplugged, went from the back of the vacuum advance module to another piece right off of the manifold, haven't been able to figure out what it is, I will upload a picture soon. Any hints on checking for vacuum leaks would be helpful, as this thing as you know, has vacuum lines all over the place. I will get back with another post and results of all work I accomplish today.
Thanks,
Zach
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Friday, February 25th, 2011 AT 9:58 PM
Tiny
CJ MEDEVAC
  • EXPERT
Need Tach. If you are too high with the idle, the Centrifugal Advance (inside the distributor) will Advance you, and you will not be accurate with timing.

If you send me a pic, include where the Vacuum Advance from the distributor runs to. Point or label, so I will see! Let me know if it's sucking constantly, or just when you crack the throttle. Or never. The kit I show has a vacuum gauge so you can be accurate with readings.

Can get a Whole Tuning kit at "Harbor Freight" less than $40.I'll show you a pic of my buddy's, Compact, and everything in one ABS container.

The Medic
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Saturday, February 26th, 2011 AT 12:53 AM
Tiny
ZACHARYTRENT
  • MEMBER
Okay, sorry it keeps taking me so long to get back on and update my status on the work. As far as I can tell all vacuum lines are connected and working how they should be. Also the centrifugal advance seems to be working as well. I took the CJ out last weekend and it ran well the entire time, right up until the point that I did some crawling and the clutch heated up, then it started acting up again, as far as losing power and wanting to stall when I tried moving, unless I kept the RPM up. I ended up advancing it a little and it did fine from that point on (interesting).
Now, in conjunction with trying to figure this issue out, I am going to try and stop the oil and transmission fluid leaks. I will be replacing the rear main seal, and the input and output shaft seals on the transmission, providing that I can figure out which transmission that I actually have. I have checked the transmission and couldnt find any identifying information on the tranny itself. After reading anything I could find I believe that the transmission is the T-176, but I need to be sure before I order the seals. Reverse is left and forward, and it is the 4 speed, and it is the 4cylinder. Any help again would be great, and if you have any other ideas as far as the lack of power, I am not giving up on that yet. Thanks again!
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Friday, March 4th, 2011 AT 4:39 PM
Tiny
CJ MEDEVAC
  • EXPERT
If your tranny has a cast iron case, you are probably right w/ the T-176

I cannot link any more here, so copy and paste this stuff onto a new tab.

Read thru these, much info is the same, look at your filter and fuel return to tank, they should be set up like mine (factory) I think there is some of that in one of these.

Don't snatch the tranny until we discuss it...it may save you some grief!

***** http://www.2carpros.com/questions/1980-jeep-cj7-timingtuning-problem-with-a *******

********* http://www.2carpros.com/questions/1984-jeep-cherokee-cj7 ********

I'm sorta in a hurry, gonna send fuel system pics now, mine have been re-routed, but still hook the same way as original....Do you have a Catalytic Converter in that thing now? Is your coil and distributor stock? You should see my reasons for asking in those posts, I just supplied.

Respond SOON!!!

The Medic
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Friday, March 4th, 2011 AT 5:15 PM
Tiny
CJ MEDEVAC
  • EXPERT
Disregard last pic, that was for someone searching for the thermostat. You could have several issues going, Vacuum, Carb, Coil (if wrong one), Even the Ignition module may be acting up. Let me know what you might want to tackle next. The Medic
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Friday, March 4th, 2011 AT 5:22 PM
Tiny
ZACHARYTRENT
  • MEMBER
CJ,
I know its been a while, but work has been keeping me between 14 and 15 hours a day for the last two months. However, now I am ready to do some more work. I ended up replacing the carburetor which ended the lack of power problems that I was having. Now I just have oil leaking from various locations and I am ready to tackle that issue. I have a new rear main seal, input and output shaft seal for the transmission, and I am going to try to find a valve cover seal to replace that while I am at it. Any advice on pulling the tranny before I jump into it?
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Sunday, May 29th, 2011 AT 4:52 PM
Tiny
CJ MEDEVAC
  • EXPERT
LETS GET SOME TERMS STRAIGHT!

BY THE WAY, I WAS GETTING WORRIED ABOUT YOU!

DID MY "ENDLESS ON AND ON" "LINKS" AID YOU MUCH WITH CARB AND TUNING?

HOW'S HE A RUNNIN'?

REAR MAIN--NO BIG DEAL, YOU AIN'T DONE IT ALREADY?

IS THAT A 2 PIECE R.M. SEAL OR ONE?

PULL THE TRANNY. LETS HEAR THE EXUSE?

WHY THE TRANNY INPUT AND OUTPUT SEAL?

ARE THEY LEAKING, . OR DO YOU MEAN THE TRANSFER CASE--FRONT AND REAR OUTPUT SHAFT SEALS?

DO THEY MAKE A HIGH VOLUME OIL PUMP FOR THAT ENGINE? (CHECK NAPA, AUTOZONE ON-LINE AND SEE) YOU'RE ALREADY GONNA BE IN THERE, THEY DO IMPROVE PRESSURE. MINE WAS ABOUT $125 10 YEARS AGO, FOR MY 258 6 CYLINDER.

I DO HAVE SOME CAUTIONS FOR YOU, WHEN DOIN' THE TRANNY THING. IF IT'S NECESSARY.

ALRIGHT SPILL YOUR GUTS AND WE WILL CONTINUE

I SUSPECT, I DID SOMETHING RIGHT, OR YOU WOULDN'T HAVE COME BACK!

THE MEDIC
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Sunday, May 29th, 2011 AT 5:22 PM
Tiny
ZACHARYTRENT
  • MEMBER
Okay,
Im glad to see your still watching out for me. This long weekend is the most time I have had to work on the Jeep. I attached some pics below so you can see the project your helping me out with. There is also some with the vacuum lines, I did my best to identify which ones go where, unless I didn't know. Additionally you will see a pic of the rear and front of the transfer case, and one of the boot around the clutch fork, and there seems to be oil coming out of there, which led me to the rear main needing replacement. I am just trying to identify where the oil is leaking from, and its proving difficult. I figured I would tackle as many seals in that area as I could to try and eliminate the problem. Whats your recommendation? If there is any other pics I can provide let me know, and I will post them ASAP. Thanks again!
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Sunday, May 29th, 2011 AT 7:52 PM
Tiny
CJ MEDEVAC
  • EXPERT
OK Boss

Click on my name/ avatar send me a message w/ your Email Address. Don't post it here for the world to see!

Me and Mr. Scanner will find you a vacuum diagram and send it to you. Should be EZer to see.

This is your next project---Pump up sprayer--Gallon of "Purple Power". Your rig is almost walk under, so you oughtta be able to mist all of the oil goo, let it sit 10 minutes. Do this at a car wash, pressure it off.

Do not get it on your paint, rinse it well anyway!

In a hurry.I will come back a little later! Discuss rest then.

The Medic
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Monday, May 30th, 2011 AT 2:12 AM
Tiny
ZACHARYTRENT
  • MEMBER
Medic,
Cant seem to figure out how to message you, maybe its just me but I don't see an option too do so after I click on your avatar. Let me know and I will send my email ASAP.
Zach
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Monday, May 30th, 2011 AT 2:42 AM

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