-   Jeep CJ Forum (
-   -   AMC 304 Idle horrible. (

Jamesromeos 05-08-2013 04:04 PM

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.

davbytrace 05-08-2013 05:47 PM

Perhaps a bad computer or sticking stepper motor in the carb...?

Matt1981CJ7 05-08-2013 06:14 PM

There is no computer in a '79, unless it was added.

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


82JeepCJ7 05-08-2013 06:34 PM

Just got one for Dad's 72 CJ5 with a 304 in it. $60 off Ebay.

jeepdaddy2000 05-08-2013 08:30 PM

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

RDH 05-08-2013 09:12 PM


Originally Posted by 82JeepCJ7 (Post 15407775)
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.

Jamesromeos 05-09-2013 12:23 AM

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?

rah2eq 05-09-2013 01:09 AM

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.

hutch1200 05-09-2013 01:25 AM

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.

Jamesromeos 05-09-2013 05:33 AM

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.

Matt1981CJ7 05-09-2013 06:00 AM

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.


82JeepCJ7 05-09-2013 08:40 AM

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.

hutch1200 05-09-2013 09:20 AM


Originally Posted by Jamesromeos (Post 15409583)
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.

Jamesromeos 05-09-2013 09:45 AM

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.

The time now is 04:08 PM.

Powered by vBulletin Version 3.8.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.