JeepForum.com - Reply to Topic
Thread: 1974 CJ5 AMC 304 - cold start stalling Reply to Thread
Title:
Message:
Post Icons
You may choose an icon for your message from the following list:
 
 
 
   

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










  Additional Options
Miscellaneous Options

  Topic Review (Newest First)
05-11-2014 07:13 PM
Mike Romain
Quote:
Originally Posted by sabbyATL View Post

Ah, did not know that. I only adjusted the one next to the fast idle cam.

What do you mean by roar on fast idle?
At least twice the speed of warmed up idle.
05-11-2014 03:28 PM
sabbyATL
Quote:
Originally Posted by Mike Romain View Post
Remember there are 2 idle screws, one for warm running and the other for the choke fast idle. You want it to roar pretty good on fast idle.
Ah, did not know that. I only adjusted the one next to the fast idle cam.

What do you mean by roar on fast idle?
05-11-2014 05:58 AM
Mike Romain
Quote:
Originally Posted by sabbyATL View Post
I can tell you I need to up the idle a little. When completely cold it's idling reeeeeeaaaaaalll low and stalls. I'll give the idle screw a half turn and test it.
Remember there are 2 idle screws, one for warm running and the other for the choke fast idle. You want it to roar pretty good on fast idle.
05-09-2014 08:42 PM
sabbyATL Thanks, both jammer1 and Matt!

I can tell you I need to up the idle a little. When completely cold it's idling reeeeeeaaaaaalll low and stalls. I'll give the idle screw a half turn and test it.

Matt, I already have the multimeter. I used it to help me figure out I blew the ignition coil.

If you have recommendations for brands for the other tools I'll get them. I always love new tools.

And, yes, I plan on maintaining the Jeep myself. I think it'll be fun!
05-09-2014 01:56 AM
Matt1981CJ7 Jen,

If you plan to continue to work on your CJ's engine, I'd highly recommend purchasing the following tools:

1. A quality digital timing light with a tach feature.
2. A vacuum/pressure gauge
3. An electrical test light.
4. A multi-meter.

With these 4 tools, you can diagnose virtually any engine-related problem, and keep it tuned.

Matt
05-08-2014 08:54 PM
jammer1 If you did not touch the fast idle screw (turn it in or out) just try starting it when cold and let it run. If you do this a few times and are happy with the fast idle you're all set . You will just have to turn the black cap to get a setting that you like (for how fast the choke turns off). When cold loosen the screws and turn the cap. When you get more resistance to turning and the choke plate closes you are setting the choke to run longer. It's trial and error. If the choke turns off before engine is warmed up enough, turn the cap to the next line (tighter resistance), if the choke was on too long (engine racing cause of fast idle screw when warm enough to run without choke), turn the cap one line in the opposite direction (less resistance).
05-08-2014 12:18 PM
sabbyATL
Quote:
Originally Posted by Mike Romain View Post
Not really. You just want it to be considerably higher than base idle. Someone posted a video a while back of fast idle sound. Mine has a fixed fan and just roars at 1750. My highway cruise rpm is about 2300 to give you an idea.

Maybe someone else with that carb can give you the screw turns in from touching?

There's this one: https://www.youtube.com/watch?v=QrEvgnruM9g

Mine sounds kind of like that...it's louder because of the headers on it but the idle sounds similar.
05-08-2014 11:37 AM
Mike Romain
Quote:
Originally Posted by sabbyATL View Post

Yes, there's basically a bunch of lines on the choke with the cap having one line. Right now it's right about center.

Now, I don't have tachometer so I don't know what my RPMs are except to be able to hear them go up or down.

Is there another way to measure RPMs?
Not really. You just want it to be considerably higher than base idle. Someone posted a video a while back of fast idle sound. Mine has a fixed fan and just roars at 1750. My highway cruise rpm is about 2300 to give you an idea.

Maybe someone else with that carb can give you the screw turns in from touching?
05-08-2014 10:31 AM
sabbyATL
Quote:
Originally Posted by Mike Romain View Post
Very cool. There is an adjustment for the choke cover. There should be an arrow on it with lines cast into the base of it. One longer line for center. Usually they set something like 2 lines rich from center. Rich is tighter.

To adjust when warmed up, just unplug the cap and the spring will unwind after a bit. Or wait...

You will want the fast idle screw when set on the closed choke position to be around 1750 rpm on a warmed up engine. You can see where the screw sits on the cam cold and off, so once warmed up the cam can be manually moved while manipulating the throttle back to that spot to set the rpm. The choke plate should stay open I think, most allow the fast idle cam to move by itself.
Yes, there's basically a bunch of lines on the choke with the cap having one line. Right now it's right about center.

Now, I don't have tachometer so I don't know what my RPMs are except to be able to hear them go up or down.

Is there another way to measure RPMs?
05-08-2014 10:12 AM
Mike Romain Very cool. There is an adjustment for the choke cover. There should be an arrow on it with lines cast into the base of it. One longer line for center. Usually they set something like 2 lines rich from center. Rich is tighter.

To adjust when warmed up, just unplug the cap and the spring will unwind after a bit. Or wait...

You will want the fast idle screw when set on the closed choke position to be around 1750 rpm on a warmed up engine. You can see where the screw sits on the cam cold and off, so once warmed up the cam can be manually moved while manipulating the throttle back to that spot to set the rpm. The choke plate should stay open I think, most allow the fast idle cam to move by itself.
05-08-2014 09:57 AM
Matt1981CJ7 Great to hear, Jen. I'm glad we could help.

Matt
05-08-2014 09:45 AM
sabbyATL It's fixed!

The new fast idle cam came in the mail yesterday. I work from home a lot (an analyst...all computers and some teleconference) so I went out and put it on. Started right up. No stalling. Idling like a champ. Making the requisite popping noises from the exhaust (that my husband and son love) when letting off the throttle.

Now, I had a little trouble getting the bimetal spring in position and I started the engine a handful of times to check the response of the choke plate. So, it wasn't truly cold when I put the choke back together. But it's there. I'll just adjust it tomorrow if it needs it.

Thanks, everyone, for helping me figure out what was wrong and getting to know chokes.

I can tell you what happened.

At some point in the past the ball weight on the old fast idle cam broke off. Either the PO did it or it was like that when he got it. Does't matter. Someone tried to rig it up to work with no ball weight. My son calls it a MacGyverism but MacGyverisms are, by definition, successful. This one was not. Basically someone wrapped a bunch of metal wire around the broken end and secured it with electrical tape, hoping that would act as the ball weight. It might've worked, weight-wise, but the bulk of the wire and tape got in the way of the cam's travel. It stopped it before it could fully reach the top end. The result was that the choke plate wouldn't fully close.

Of course, when I was investigating the cam I broke it. But the plastic was "dry-rotted". I think the cam was probably pretty old and plastic gets very brittle with age and lots of heat exposure, which a cam will of course have. So, the cam basically crumbled.

After that I didn't have problems starting but it idled way high without relief.

This morning I installed the new cam and it idled the way it did before, only now it is no longer stalling.

The choke may need adjustment tomorrow or later this afternoon when it's cold but the issue seems to be resolved.

Thanks a lot, guys!
05-05-2014 09:06 PM
sabbyATL So, I didn't get the manual choke conversion kit. I decided to just try to repair the electronic choke and if it gives me more trouble, or if the same problem with cold start is still a problem, I'll convert to manual. Simply because the electronic choke is pretty new. I found the receipt for it in the Jeeps documentation (the PO gave all his receipts to me). So, I bought a replacement cam and it should come in Wednesday.

Anyway, I drove it this afternoon. It started up with no stalling. And at first it sounded great. But after it warmed up it was idling really high. Or, it sounded high to me. I don't have a tachometer on the Jeep. But it sounded way way higher than it was before. At the same time...I have no idea if the way it idled before is good or not. But that's my reference point.

So, it would seem that breaking the fast idle cam in the way I broke it means it is stuck on fast idle.

Otherwise, it ran great. It was just sitting at traffic lights and such that it didn't sound right.
05-04-2014 07:40 PM
jammer1 The red arm rides on a shaft. Picture putting a ring on a pencil. You can turn the ring on the pencil. The only difference is it may not turn completely around (something mighty hit the arm while turning, can't remember).
05-04-2014 07:27 PM
sabbyATL
Quote:
Originally Posted by jammer1 View Post
Without the weight (in the cam), the cam is now in the fast idle position. The fast idle screw is hitting it and opening up the throttle. If he were to back out the screw it wouldn't contact the cam. When he get's home, pull the air cleaner off, open the throttle and push the cam toward the fast idle screw. Close the throttle, then go to the drivers side and look at the idle screw. you should see that it's not contacting the throttle lever. For a manual choke you run a cable from below you're dash to the manual choke lever. On the bottom of the dash you mount (two screws) a bracket (approx. 1" x 1") that the cable mounts to. To start the engine you step on gas, pull cable all the way out (approx 2.5") then push in about 3/8". Hit gas one more time and turn key. You will have to play around with how far the cable needs to be out or in. I don't know you're age, but if you're in you're 40's or older (or you're father's around) they can help since they were used more back then. If you like the electric choke, get the red fast idle arm and install it and you should be ready to go. If you go manual, get the holley. The kits they sell to replace the black cap with another black cap don't work nearly as well as the holleys original kit.

Ok, I'll test this tomorrow.

What does it mean that I can flip the cam back and forth like a light switch? What I mean is that it might be In the "forward" position, where it's down and, I think, away from the fast idle screw. Then, with my finger I can flip it to the "back" position where it's against screw. But there doesn't seem to be positions between forward and back, like the way a light switch works.

I did see the black cap conversion kits but, like you said, the official Holley kit looks like the best quality.

Those kits don't come with the cable and knob, do they? That's probably cheap, though.

Oh, and I'm 40. I don't think I've driven a car with a manual choke before but the 80s and early 90s I used to drive around my Dad's hunting camp on 3-wheelers that had manual chokes. And with this whole thing I feel like I have an understanding of how they work.

I'll update tomorrow or Tuesday.

Thanks, again!
This thread has more than 15 replies. Click here to review the whole thread.

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

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