AMC 304 Idle horrible. - JeepForum.com
 
LinkBack Thread Tools
post #1 of 14 Old 05-08-2013, 03:04 PM Thread Starter
Jamesromeos
Registered User
1979 CJ5 
 
Join Date: Oct 2012
Location: Danvers
Posts: 246
AMC 304 Idle horrible.

I have a question regarding the Idle of my CJ. It has a points 304 in it. The Jeep is idling odd, it is almost as if there is an extreme cam in it, and there is not. going from 400 to 1000 up and down RPM's. I put a full exhaust on it today, and it is still doing the same thing, more pronounced now that I have a complete and semi quiet exhaust. Could this be a result of old technology? I have been saving to put HEI on it, kind of on the back burner with a mortgage and a truck payment. Advice is appreciated.

Jamesromeos is offline  
Sponsored Links
Advertisement
 
post #2 of 14 Old 05-08-2013, 04:47 PM
davbytrace
Registered User
1979 CJ7 
 
Join Date: May 2011
Location: clinton
Posts: 487
Perhaps a bad computer or sticking stepper motor in the carb...?
davbytrace is offline  
post #3 of 14 Old 05-08-2013, 05:14 PM
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 16,454
There is no computer in a '79, unless it was added.

James, what carb are you running, and how long since the last rebuild?

Matt
Matt1981CJ7 is online now  
post #4 of 14 Old 05-08-2013, 05:34 PM
82JeepCJ7
Registered User
1982 CJ7 
 
Join Date: Jun 2010
Location: Marysville, WA
Posts: 5,415
Just got one for Dad's 72 CJ5 with a 304 in it. $60 off Ebay.

Beat it to fit, paint it to match!

Wheel, Wrench, Repeat.
82JeepCJ7 is offline  
post #5 of 14 Old 05-08-2013, 07:30 PM
jeepdaddy2000
Registered User
 
jeepdaddy2000's Avatar
1971 CJ5 
 
Join Date: Jan 2002
Location: Eagle Point
Posts: 7,003
The best thing to do is to start at the beginning.
Clean and adjust the points (dwell)
Check the timing
Insure the firing order is right and the wires are solid
Insure the plugs are good and gapped
Check for manifold leaks including the power brake booster
make sure the choke is off, power valve is good, and adjust the idle mixture

You can check to see if all the cylinders are firing by pulling the wires one at a time. You should get a noticeable RPM drop on every plug
jeepdaddy2000 is offline  
post #6 of 14 Old 05-08-2013, 08:12 PM
RDH
Registered User
 
Join Date: Mar 2013
Location: Tavares
Posts: 179
Quote:
Originally Posted by 82JeepCJ7 View Post
Just got one for Dad's 72 CJ5 with a 304 in it. $60 off Ebay.
I'm thinking about that exact Dizzy...PM me and let me know how it works out for you.

My Holley 4412 was doing the same thing. Adjusted the mixture and the idle screw and everything evened out. Oh, I also had to adjust the float level, was WAY low. Just giving you some starting points.

1978 CJ7: 304, 3Spd, AMC 20 Rear, Thrush Welded Mufflers W/ Turndowns, Unknown Front, Worn out Dana 20 case
RDH is offline  
post #7 of 14 Old 05-08-2013, 11:23 PM Thread Starter
Jamesromeos
Registered User
1979 CJ5 
 
Join Date: Oct 2012
Location: Danvers
Posts: 246
Matt, I am running a 600 edelbrock, it is about a year old, been on this jeep about 2 months. I am leaning toward just doing the HEI anyway...can only improve. How hard is the swap? Just literally swap the distributor and time her?
Jamesromeos is offline  
post #8 of 14 Old 05-09-2013, 12:09 AM
rah2eq
Registered User
1978 CJ5 
 
Join Date: Nov 2011
Location: Richmond
Posts: 119
My advice is to search high and low for a vacuum leak. Mine was doing the same thing, and it was the combination of vacuum leaks and timing. In my case it was mostly timing, mine was way too far advanced. I'd check these two things; I think a new distributor will almost always help, but in my opinion it shouldn't cause any sort of fluctuation throughout a large RMP range as you stated.
I put in an DUI HEI a few months ago and the installation is painless. I'd warn you to read up on the issues that new distributor gears have caused and I urge you to either swap out your old distributor gear and put it into the new distributor or buy a (hardness) matched set from Bulltear or elsewhere. Otherwise chances are that you'll tear up your cam gear which can quickly destroy your engine.

1978 CJ5 - 304 V8 - Twin Sticked and sitting on 35's
2010 JK- Rock Krawler 2.5" on 35" KM2's
rah2eq is offline  
post #9 of 14 Old 05-09-2013, 12:25 AM
hutch1200
Recovering Bronco Rider
 
hutch1200's Avatar
1979 CJ7 
 
Join Date: Feb 2007
Location: Clarks Summit
Posts: 3,214
What rah2eq said about the dizzy gear is Gospel. You HAVE to put your old dizz gear on this new unit.
And 82jeepCJ7, Did you do a rebuild w/new cam? If so, I bought mine from skip white and it was a hardened steel gear. Couldn't nick it in my drill press. That new diz gear would have chewed my new Comp Cams' gear right up. I had to put an MSD p/n 8005 $55) iron gear on.

I've also learned that sometimes... when people don't agree with you .... its best to hold them down and kidney punch them till they agree with you
hutch1200 is offline  
post #10 of 14 Old 05-09-2013, 04:33 AM Thread Starter
Jamesromeos
Registered User
1979 CJ5 
 
Join Date: Oct 2012
Location: Danvers
Posts: 246
How do the gears come off the distributor? To do both gears do I have to take apRt the timing cover? Would like to avoid that.
Jamesromeos is offline  
post #11 of 14 Old 05-09-2013, 05:00 AM
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 16,454
In my opinion, the surging idle is more likely air, fuel, or vacuum related, not ignition.

The HEI will certainly be an upgrade over points, but don't be surprised if it doesn't cure your problems.

Matt
Matt1981CJ7 is online now  
post #12 of 14 Old 05-09-2013, 07:40 AM
82JeepCJ7
Registered User
1982 CJ7 
 
Join Date: Jun 2010
Location: Marysville, WA
Posts: 5,415
I got the HEI from White Performance. I had already planned on swapping the OEM gear onto it. I did the same thing with my HEI. This one is going into Dad's 72 CJ5. I spent the last week rewiring and re-plumbing it.

Swapping gears takes about 5min (4 of that would be looking around my shop for the right punch). Just push out the roll pin, swap dizzy gears, put it back. Done.

Beat it to fit, paint it to match!

Wheel, Wrench, Repeat.
82JeepCJ7 is offline  
post #13 of 14 Old 05-09-2013, 08:20 AM
hutch1200
Recovering Bronco Rider
 
hutch1200's Avatar
1979 CJ7 
 
Join Date: Feb 2007
Location: Clarks Summit
Posts: 3,214
No

Quote:
Originally Posted by Jamesromeos View Post
How do the gears come off the distributor? To do both gears do I have to take apRt the timing cover? Would like to avoid that.
82 has the skinny on the gear swap.
When he pulls the cap, is it OK just to mark exactly where the rotor is pointing, or should he do it from TDC etc...I always used pinstripe tape straight down the rotor, dizzy and onto the intake or whatever it leads to. Then cut the tape @ the dizzy. Then line the new rotor up w/the tape. Bad practice on my part?
Matts right too. This is just a baby step in the right direction. Be prepared for a less than 100% cure.

I've also learned that sometimes... when people don't agree with you .... its best to hold them down and kidney punch them till they agree with you
hutch1200 is offline  
post #14 of 14 Old 05-09-2013, 08:45 AM Thread Starter
Jamesromeos
Registered User
1979 CJ5 
 
Join Date: Oct 2012
Location: Danvers
Posts: 246
I think it is time to go HEI anyway, however I'm going to check timing today as well as vaccum. Is it 5 degrees before tdc? I forget.
Jamesromeos is offline  
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.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome