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Unread 09-07-2011, 03:14 PM   #1
rancho_26
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89 Wrangler 4.2L idles way too fast with weber carb

I finally got my new 32/36 Weber carb last Sunday. I installed it on Monday and finished up everything else that wasn't done the next day. The good news is that my Jeep fired right up after sitting for 9 days. Even better news is that everything is working the way it should. Fuel lines are good, new fuel pump and fuel filter, electric choke is working, etc.
But when I start my Jeep, it idles up to about 2000-2500 RPM, then slowly increases to 3000.

This is where I'm stuck. I checked my throttle linkage and it is working like it should. I don't know what to do next.


EDIT: Choke works fine. I turned the idle screw all the way back until it wasn't touching the throttle, same thing with the fast idle and still no luck.
Tried to kick the throttle and it just idles even higher. Maybe it is a vac leak, but I won't find out until tomorrow.

And I did go through the tune procedure and still nothing.


@Tompatt I nuttered that thing over a year ago. I have a HEI dist now. Must have done something right because it didn't haven't any problems before I got my new carb.

Most likely a vacuum leak that I can't find.

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Last edited by rancho_26; 09-07-2011 at 10:21 PM..
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Unread 09-07-2011, 03:59 PM   #2
giggityjeeper
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choke is stuck....

idle is to high on the idle screw.....

fuel mixture screw is wrong....

can only really be one of those 3...

when it idles high if you kick the throttle down and let it back on its own, like smack it kinda with your foot, my choke will stick sometimes and idle at 1700, I kick the throttle to get it off, and it returns to 800ish

EDIT... could be a vac leak in your gaskets and **** to, maybe
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Unread 09-07-2011, 04:18 PM   #3
dtn8tr
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The webers are designed to run at 1700-2000 high idle if started properly. When you hit the pedal again it will kick out the high idle and should drop back to the idle speed that you set up. Have you gone through the tune procedure to set the choke and and then set the curb idle after warmed up?
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Unread 09-07-2011, 07:08 PM   #4
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Sounds like a VACUME leak to me
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Unread 09-07-2011, 07:32 PM   #5
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you nuttered correct?
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Unread 09-09-2011, 09:13 AM   #6
mcmud
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Wanted to check in on this, have you resolved this issue?
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Unread 09-09-2011, 12:04 PM   #7
giggityjeeper
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Quote:
Originally Posted by dtn8tr View Post
The webers are designed to run at 1700-2000 high idle if started properly. When you hit the pedal again it will kick out the high idle and should drop back to the idle speed that you set up. Have you gone through the tune procedure to set the choke and and then set the curb idle after warmed up?
no they idle at 750 ideally..... if it is revving that high, the choke is on which makes sense at startup, if it continues, then your choke is sticking, or a vac leak somewhere... a vac leak would usually make it idle worse, but ya never know
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http://www.jeepforum.com/forum/f12/f...grade-1054753/

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Unread 09-09-2011, 12:29 PM   #8
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Quote:
Originally Posted by giggityjeeper View Post
no they idle at 750 ideally..... if it is revving that high, the choke is on which makes sense at startup, if it continues, then your choke is sticking, or a vac leak somewhere... a vac leak would usually make it idle worse, but ya never know
Giggity...they idle at 700-800 normal...but high idle when you start it is actually supposed to be set at approx. 2000rpms per Weber instructions. Once you hit the pedal after starting it, it will drop down to normal idle.
The instructions for starting with the Weber says to press the pedal in and release to set the high idle cam with the key off.
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Unread 09-09-2011, 03:01 PM   #9
rancho_26
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Quote:
Originally Posted by dtn8tr View Post
Giggity...they idle at 700-800 normal...but high idle when you start it is actually supposed to be set at approx. 2000rpms per Weber instructions. Once you hit the pedal after starting it, it will drop down to normal idle.
The instructions for starting with the Weber says to press the pedal in and release to set the high idle cam with the key off.
Still haven't got it. I hit the pedal after starting but it only seems to make it increase the RPM's even faster. I'm just completely confused why it increases all the way to 3000. I even disconnected the throttle linkage and made sure it wasn't sticking.
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Unread 09-09-2011, 03:05 PM   #10
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Originally Posted by mcmud View Post
Wanted to check in on this, have you resolved this issue?
No, I haven't. It's a little frustrating. As the installation guide says, the choke is suppose to be closed all the way before cold starting. And it is closed all the way and opens up a bit after starting. I even backed the fast idle screw all the way off but I still get the same thing.
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Unread 09-09-2011, 03:50 PM   #11
mcmud
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If the choke plates are continuing to full open as the engine warms and the fast idle continues look here for some cause/bind that this rod will not allow movement of the fast idle lever.

This rod connects two levers and both must be able to move freely (up and down) while the choke plates are fully opened and the throttle is opened to some degree.

Photo courtesy of Swatson454
swatson454-fastidle-control-rod.jpg  
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Unread 09-09-2011, 04:19 PM   #12
rancho_26
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Quote:
Originally Posted by mcmud View Post
If the choke plates are continuing to full open as the engine warms and the fast idle continues look here for some cause/bind that this rod will not allow movement of the fast idle lever.

This rod connects two levers and both must be able to move freely (up and down) while the choke plates are fully opened and the throttle is opened to some degree.

Photo courtesy of Swatson454
Already good news and bad news.

The good news is that it no longer idles too high. Turns out that a lever on the throttle linkage (the one with the black spring) wasn't hooked on right.

The bad news is that my Jeep now runs rough and dies if I don't get on the gas. It acts as if it's not getting enough gas.
Thank you everyone, but unfortunately I have another problem.
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Unread 09-09-2011, 04:40 PM   #13
mcmud
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It isn't that it isn't getting enough gas...if it ran at 2K there is ample fuel reaching it and it should idle just fine. The issue is now in the screw settings, fuel is not being discharged at the right strength at the right spot.

If you have the Redline tune guide rely on each and every word within it and follow each step, if you need the document give a quick shout and I'll post one for you.
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Unread 09-09-2011, 05:31 PM   #14
rancho_26
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Quote:
Originally Posted by mcmud View Post
It isn't that it isn't getting enough gas...if it ran at 2K there is ample fuel reaching it and it should idle just fine. The issue is now in the screw settings, fuel is not being discharged at the right strength at the right spot.

If you have the Redline tune guide rely on each and every word within it and follow each step, if you need the document give a quick shout and I'll post one for you.
No, unfortunately I don't have one. I'd be more than happy if you did post one.
I thought it was the screw settings, but I can't work on it till tomorrow.
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Unread 09-09-2011, 06:58 PM   #15
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Here you are.
dg-20series-20003.jpg  
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