1978 Cj 5 304 v8 engine trouble - 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 > General Technical Discussions > Engines & Drivetrain > 1978 Cj 5 304 v8 engine trouble

Rampage Bowless Soft Top Oconee offroadAlloy USA Still AvailableAdvance Adapters SYE Kits

Reply
Unread 10-14-2013, 08:00 PM   #1
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
1978 Cj 5 304 v8 engine trouble

Have 1978 Cj 5 it's running on 6 cylinders? Can't figure out what's wrong with the 2 cylinders. They are getting spark i changed all the spark plugs. I made sure all the wires were working? Does any one have any ideas?

djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 03:27 AM   #2
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,962
Could be a bad cam. Nit opening the intakes for them.
Is it smoking? Making noise? Maybe the springs or push rods. Do you which cylinders are dead?
Maybe the jeep wants a straight six now, lol. Just kidding trying to lighten the mood.
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 02:49 PM   #3
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
It's cylinder 1 and 5 I believe. It back fires if I get on the throttle
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 02:49 PM   #4
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
]It's cylinder 1 and 5 I believe. It back fires if I get on the throttle and there's no smoke
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 06:33 PM   #5
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,962
Well since they're both on the same side I would suggest disconnect the coil wire then pull that valve cover and have some one crank the motor over that way you can get a better idea of whether its push rods or springs or the cam.
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 09:37 PM   #6
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
Sorry it was cylinder 8 and 5
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 12:37 AM   #7
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,962
Should still pull the covers you'll be able to see better
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 12:45 AM   #8
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
Ok thanks a lot I'll do that tomorrow
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 10:31 AM   #9
Red Rubicon
Registered User
2003 TJ Wrangler 
 
Join Date: Jun 2002
Location: Mt. Shasta, Ca
Posts: 130
Your first step should be to check compression.
Red Rubicon is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 08:03 PM   #10
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
Compression was 90 at all cylinders
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 10:02 PM   #11
djmarine
Registered User
2006 TJ Wrangler 
 
Join Date: Nov 2008
Location: Jacksonville, Nc
Posts: 55
Also when it started happening my fuel gauge and temp gauge stopped working not sure if that has anything to do with it but need to get that fixed to
djmarine is offline   Reply With Quote Quick reply to this message
Unread 10-21-2013, 09:05 AM   #12
tineyhairs
Registered User
1975 CJ5 
 
Join Date: Aug 2013
Location: lockport, ny
Posts: 17
dead cylinders

is it back firing thru the carb or exhaust? intake would be intake valve not working or thru exhaust exhaust not working. as was said in a previous thread pull valve cover off and the coil wire. check the push rod if its there. check valve lash at bottom dead center for looseness. take all spark plugs out. crank the engine and watch the 4 intake and exhaust valves of the 2 cylinders in question. if they don't move or move little compared to the others, you have a bad cam lob. others reasons, v-springs rocker arms, push rods will be obvious. 1 more thing is if the lifter has collapsed the rocker arm may not move. reason for removing all s-plugs is the engine will turn over much easier as there will be no compression in any cylinder. gook luck. take your time and be thurl.
tineyhairs is offline   Reply With Quote Quick reply to this message
Unread 10-21-2013, 09:12 AM   #13
tineyhairs
Registered User
1975 CJ5 
 
Join Date: Aug 2013
Location: lockport, ny
Posts: 17
cam

what cams have you all used in your 75 cj5 304? just want a little ruff idol compared to stock.don't want to change springs locks. the thumper cam is what i wanted, but they said i had to change the works and it would be around $500 bucks. cam and lifters is all i want. not looking for HP just a little ruff idol. tks for the help

have one on me
tineyhairs is offline   Reply With Quote Quick reply to this message
Reply

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






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.