CJ7 running oddly - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > CJ7 running oddly

NEW!! HMF 50"-52" light bar mounting brackets!! Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineYear End Clearance Sale! Save 20%

Reply
Unread 05-31-2012, 05:41 PM   #1
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
CJ7 running oddly

Let me start witha little back story. I have been looking through the forum for a few days now trying to find someone who has had the same problem but have had no luck.

I bought my 84 Jeep CJ7 with a few problems with the intent of fixing them all.
My valve cover was the stock plastic one which leaked oil like crazy - replaced it with a cast aluminum one.
My water pump went out on the drive home after purchase - replaced it.
The stock carter carb ran OK at best - so i replaced it with a 1.08 Motorcraft 2100 that I got from ebay. I did a rebuild and made the custom brackets for the throttle linkage.
I started it up with the vac gauge attached and everything looked great. Ran smooth and it measured at about 19. Throttle response was great and all the power was there. Ran it down the street with no issues. Thought it was done and perfect.
BUT THEN i reved it up to maybe 2500 and heard a pop from under the engine compartment. The engine started to run roughly and the vac gauge was bouncing back and forth. I tried to see if there was anything obvious under the hood but nothing stood out. THEN after a minute or two the engine calmed down and got smooth. The vac reading went back to normal. I tried driving it around a little bit but under load the engine seemed to want to cut out. I had to feather the clutch and give it lots of gas.

I checked under the valve cover for a bad spring but again nothing stood out. Everything seemed OK.

So im stuck. Has anyone ever run in to anything like this before?

Thanks for the help!

rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 05:57 PM   #2
keman
Registered User
1984 CJ8 
 
Join Date: May 2012
Location: Auburn, WA
Posts: 110
Still running stock ignition? For some reason, I would check the vac advance unit on the distributor. Not really sure, but that's just what came to mind first.

Did you bypass the ECM when you changed carbs? If not, a simple bypass will allow you to remove 90% of the ridiculous unneeded vac system. Research Nutter bypass, or take it one stop further and replace the distributor with an HEI diz. Thunderchicken has new ready to install units for a great price. Mine was under $80 shipped.
__________________
Admin of The DV Sanctuary, a non profit resource center helping survivors of violence.
keman is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 06:03 PM   #3
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
Quote:
Originally Posted by keman View Post
Still running stock ignition? For some reason, I would check the vac advance unit on the distributor. Not really sure, but that's just what came to mind first.

Did you bypass the ECM when you changed carbs? If not, a simple bypass will allow you to remove 90% of the ridiculous unneeded vac system. Research Nutter bypass, or take it one stop further and replace the distributor with an HEI diz. Thunderchicken has new ready to install units for a great price. Mine was under $80 shipped.

Ah i forgot to mention that all of the vac stuff has been removed by a previous owner so there is nothing to worry about there.

And im not sure about the ignition but I dont think it is stock.

Vac advance is running fine from what i can deduce but i will check out the distributor tonight anyway.
rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 06:09 PM   #4
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert, CO
Posts: 10,990
Get some pictures of your engine compartment posted up, so that we know what you are running.

And fill out your profile as completely as you can. That will help a bunch.

Matt
Matt1981CJ7 is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 06:11 PM   #5
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
Here are a few pics of the engine bay.


http://imgur.com/a/W9sPK
rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 06:17 PM   #6
keman
Registered User
1984 CJ8 
 
Join Date: May 2012
Location: Auburn, WA
Posts: 110
Looks like you already have an HEI diz. Where is the vac advance getting it's vac from? Make sure it is a manifold vac source.
__________________
Admin of The DV Sanctuary, a non profit resource center helping survivors of violence.
keman is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 06:34 PM   #7
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
Quote:
Originally Posted by keman View Post
Looks like you already have an HEI diz. Where is the vac advance getting it's vac from? Make sure it is a manifold vac source.

Right now we had the vac advance coming from the carb - thats where it was attached on the stock carb when i bought the jeep so i just assumed thats where it went.
rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 08:42 PM   #8
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
just checked the rockers - each one was tightened to the proper spec - over the weekend ill remove each one and inspect them more closely
the distributor looked fine but i cleaned all of the contacts just for kicks
rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 08:54 PM   #9
Mickey_Mouse
Registered User
2013 KK Liberty 
 
Join Date: Dec 2011
Posts: 726
your Cam could need to be replaced
Mickey_Mouse is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 09:11 PM   #10
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
Quote:
Originally Posted by Mickey_Mouse View Post
your Cam could need to be replaced
Wouldnt a bad cam give me a constant problem not just one that went away after a few minutes?
rtormet is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 09:16 PM   #11
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali, Indonesia
Posts: 4,685
Looks like the Teamrush upgrade on the Motorcraft dizzie with something on the coil end. Hard to say exactly how it is plumbed togather but I would hazard a guess that your timing is governed by a basic Motorcraft setup, same as a standard CJ. If you have Motorcraft stamped on the vacuum capsule on the dizzie then it is for sure. The Motorcraft dizzie is a good piece of kit and worth keeping but checking for full operation and wear, you can buy quality parts to rebuild it if needed.

The symptoms you describe sound like a foreign object in the intake passing through the valves. When you had it all apart did you cover the inlet? It is awfully easy to drop a nut down there and it will pass through the engine once the revs build up. I would suggest a compression check on all cylinders to verify the cylinders and valves are within spec.
__________________
BagusJeep lives in Bali, the Land of Temples.
With a Jeep every prayer counts.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 09:20 PM   #12
keman
Registered User
1984 CJ8 
 
Join Date: May 2012
Location: Auburn, WA
Posts: 110
Quote:
Originally Posted by rtormet View Post
Right now we had the vac advance coming from the carb - thats where it was attached on the stock carb when i bought the jeep so i just assumed thats where it went.
Switch it to manifold vac.

I have had a vac advance diaphram tear in the past, caused all sorts of odd problems. Put a short hose on it and suck hard (no bad jokes guys). If it passes air, it's bad.
__________________
Admin of The DV Sanctuary, a non profit resource center helping survivors of violence.
keman is offline   Reply With Quote Quick reply to this message
Unread 05-31-2012, 09:21 PM   #13
rtormet
Registered User
1984 CJ7 
 
Join Date: May 2012
Location: Seviile, OH
Posts: 15
Quote:
Originally Posted by BagusJeep View Post

The symptoms you describe sound like a foreign object in the intake passing through the valves. When you had it all apart did you cover the inlet? It is awfully easy to drop a nut down there and it will pass through the engine once the revs build up. I would suggest a compression check on all cylinders to verify the cylinders and valves are within spec.

Hmm yea i tried to keep everything covered and never lost a part or anything into the intake. Compression was fairly consistent on all cylinders. 120 on all except #5 at 110

not exactly sure what spec is for compression tho
rtormet is offline   Reply With Quote Quick reply to this message
Unread 06-01-2012, 03:03 AM   #14
Mickey_Mouse
Registered User
2013 KK Liberty 
 
Join Date: Dec 2011
Posts: 726
the cam and distributor go hand in hand. if you heard a loud pop, I would say a bearing in the motor. never over-rev a motor: in any gear: if anything else, check the carb again. did anything look odd with the distributor cap? bearings, springs, contacts?
Mickey_Mouse is offline   Reply With Quote Quick reply to this message
Unread 06-01-2012, 03:44 AM   #15
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali, Indonesia
Posts: 4,685
Factory specs were 120-150 psi with max variation 30psi. Sounds like your compressions are good, were these measured after the episode?
__________________
BagusJeep lives in Bali, the Land of Temples.
With a Jeep every prayer counts.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline   Reply With Quote Quick reply to this message
Reply

Tags
idle issue , motorcraft 2100 , rough idle

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.