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Unread 08-02-2011, 05:54 AM   #1
bazz
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1989 YJ Wrangler 
 
Join Date: Sep 2004
Location: where ever the Army sends me
Posts: 175
weird idle flooding issue

4.2 weber 34/34 carb th999 auto

If I let it sit at idle for more than 10 minutes it starts running like crap an then stalls out and floods. Then has a hard time starting (flooded) and when I do get it started it runs like total crap, if I get on the go petal it loses power almost like the timing is way off.

Now if I kill it and let it sit for about 30 mins it fires up and runs fine. Another thing it does is when it idles the cat will glow red.

The timing is set at about 9 degrees (12ish with the vac like attached)

I'm pretty sure the carb is out of adjustment but I can't find a diagram of my specific carb (weber 34/34) and I don't know squat about carbs I know the idle fuel (?) Adjustment screw is on the drivers side under the choke and I have that backed out 2 turns weird thing is if I put that screw all the way in it doesn't starve for fuel and die?

Any ideas or at least a detailed how to to adust this specific cab? I've seached but have not found my carb.

Thanks!

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Unread 08-02-2011, 07:56 AM   #2
4.7stroker
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1988 YJ Wrangler 
 
Join Date: Apr 2007
Location: Rio Rancho NM
Posts: 4,299
You will need Mcmudd to help you tune that carb.
As for the timing one thing the nutter bypass doesn’t address is the need to change your distributor to a pre-smog item like the 1981 Jeep used. Sure your Jeep will run without changing your dizzy but you are leaving a lot on the table if you don’t change it. Here is where I got my information http://www.jeepforum.com/forum/f8/wo...w-tune-973904/
And this is the part I ordered http://shop.advanceautoparts.com/web...RPTUNEAMS____#
I found that before the swap my stroker motor was rather lazy and didn’t live up to my expectations, sure it ran and had reasonable power but I thought is was lacking some will to live. After the swap now the motor is eager to please and will even lay down 2 12” wide black stripes if I choose to be generous with the stupid pedal. I will say to anyone that has nuttered the engine that they are missing out if they don’t finish the job and install a pre-smog dizzy.

Dwayne
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Unread 08-02-2011, 12:27 PM   #3
pasinbuy
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1994 YJ Wrangler 
 
Join Date: Feb 2007
Location: florida
Posts: 3,839
It sounds to me that your float bowl needle is not stopping the gas from going into the cylinders when the float bowl is full.

If your motor is dying when you hit the gas it may be that too much gas is injected into the cylinders by the plunger. I do not know if your plunger is adjustable, if it is set it to inject less gas.

Does your motor oil have a gas smell at all?

May be time for a carb rebuild.
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Unread 08-02-2011, 12:42 PM   #4
tslroper
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1990 YJ Wrangler 
 
Join Date: Aug 2010
Location: New Mexico
Posts: 380
Wow, I just spent several weeks troubleshooting this same issue. I have a 4.2L with a motorcraft carb and the same tranny. In my case atleast, the carb was way out of tune. Once we got that set right it has run fine. I'm not familiar with Weber carbs at all, but have seen a few posts with instructions on how to tune them. I'm sure if you do a search on here for how to tune a weber you'll find a lot of information.
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Unread 08-02-2011, 01:42 PM   #5
4.7stroker
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The forum is on crack and won't let me post a link.

Dwayne
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Unread 08-02-2011, 01:51 PM   #6
4.7stroker
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Main Weber Page

CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT


Proper idle jets are very important to a Weber's performance
( this assumes there is no vacuum leaks or other carb problems check here)

Idle Speed Screw should be no more than 1 1/2 turns in (Fig 1)
Poor Idle
Good Idle

Mixture Screw
Less than 1 turns out Go down on the primary idle jet
Mixture Screw
more than 2 turns out Go up on the primary idle jet
Mixture Screw
between 1 and 2 turns out Primary jet is correct size

It is important to follow all linkage and lever installation instructions. The number one and two reasons for tuning errors are improper linkage installations and over tightened linkage nut, causing a binding in linkage assembly.

CALIBRATIONS MAY VARY DUE TO REGIONAL FUELS AND STATE OF ENGINE TUNE AND PERFORMANCE. POOR RUNNING QUALITY DOES NOT MEAN A DEFECT IN THE CARBURETOR. AN ADVANTAGE OF THE WEBER CARBURETOR IS ITS EASE OF ADJUSTMENT AND TUNING.

SET UP ADJUSTMENTS

Start set up by confirming carb base line settings. Do not depend on the factory delivered settings. Check them before the carb is installed.

1. All settings are done with choke disengaged or warmed up so that the choke is fully opened and disengaged. This is done on automatic choke carburetors by first opening the choke butterfly by hand and inserting a wood block or wedge of some kind to hold open while the linkage is cycled (linkage operated through its full movement) to clear the choke cam. (You will hear a metallic click as the cam is released. You can check the fast Idle screw under the choke assembly to confirm that it is not in contact with the choke fast idle cam.)

2. Set the Idle stop screw (speed screw see fig 1) by backing out the Idle speed screw until it is not in contact with the throttle stop lever. Cycle the linkage again to be sure that the linkage comes to close without any assistance. (Checking for linkage bind) Now bring screw back into contact with the lever and continue to open or screwing in 1 turn no more than 11/2 turns.

3. Set the mixture screw (see Fig 1) by first screwing in until the screw stops, bottoms out. DO NOT FORCE OR BIND AS THIS WILL CAUSE DAMAGE TO THE SCREW AND IT’S SEAT IN THE BODY OF CARBURETOR. Back out the screw 2 full turns.

4. TUNING

BE SURE TO FOLLOW THE NEXT INSTRUCTIONS IN THE PROPER SEQUENCE, DEVIATION WILL CAUSE THE CARBURETOR TO NOT FUNCTION TO ITS IDEAL SPECIFICATIONS AND MAY NOT PROVIDE THE PERFORMANCE AND FUEL ECONOMY AS DESIGNED.

4a. Start the engine, the engine will run very slowly more like a tractor. As long as the engine stays running idle speed is not important at this point.

4b. The first thing to do is not set up the idle speed, but to set the idle mixture screw to lean best idle setting. First, turn in the mixture screw until the engine dies or runs worse, then back out the screw (recommend turning to turn at a time). The engine should pick up speed and begin to smooth out. Back out turn more, or until the screw does nothing or runs worse then turn back to the point where it ran its best. Use your ear, not a scope or tuning instruments at this point. You want to tune the engine by sound. Adjust to best, fastest and smoothest running point.

4c. Now that the mixture screw is at its best running location, you can adjust the idle speed the screw. The screw will be sensitive and should only take to turns to achieve the idle speed you like.
Check and set idle to your driving preference. Put the car in gear and apply slight load, (AC on) and set the Idle as you like it. Don’t set it too high, as this will cause causes excessive clutch and brake wear. The Idle only needs to be 7 to 900 RPM with light load or AC on.

5. Recheck timing and vacuum hook ups. Recheck mixture screw to lean best idle again. If all is still best and smoothest idle then confirm and note the final settings.

To confirm settings with the engine running. Start by screwing in the mixture screw and count the number of turns it takes to bottom out and note if the engine dies. If Idle Mixture screws are with in turn of base line setting then all is well and have fun. Also check the speed screw and note how many total turns from initial contact. You may have opened (turned in) the speed screw. Your final setting should be under 2 full turns. Reset the screws (back in) to the best final settings (Per your notes) and go on a test drive and have fun. If the settings are other than described then you may want to recalibrate the idle circuit (low speed circuit) to your engines needs. This is done by following the rule of thumb BELOW.

Simple Rules for low speed calibration

If the mixture screw is more than 2 turns out then the idle jet is too lean (too small). When the mixture screw is less than 11/2 then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 11/2 turns. If the speed screw has to be opened 2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition. See pictures and notes in the tech 2 article supplied in the kit instructions, view and please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size. JET KITS are available if needed.

EXAMPLE With the speed screw set at no more than two (2) turns in after contact with the stop lever; and the best idle occurring with the mixture screw set at 3 turns from bottom, indicates the need for a larger Idle jet. Achieving the best idle at under 2 turns indicates the need for a smaller idle jet.

The secret to understanding the critical nature of the carburetor set up and the advantages of a WEBER over other carburetors is the idle circuit. Referred to as the low speed circuit by Weber, this circuit is responsible for 80% of the driving operation. This is the reason that the Weber should give a fuel economy improvement over most factory carbs along with significant performance gains. In the worst case you should not see a significant fuel economy loss over stock, while improving HP & Drivability.

The Weber Carburetor is a sequentially timed device to the motor like the distributor. Time taken in the setup will provide more fun later.

If you should need to call REDLINE WEBER for technical assistance we will need to know your final settings to help. Technical assistance is free for the first 60 days of purchase. Units in service over 60 days may be assessed a service fee. All charges will be noted up front after a brief consultation to determine any possible defect. If the carb is out of the warranty period and no defect is determined we will estimate the possible cost of tech support or recommend literature available that may help.

ALL WARRANTIES ARE HANDLED DIRECTLY THROUGH REDLINE WEBER NOT THE RETAILER. DO NOT SEND PARTS TO MANUFACTURER WITHOUT CALLING FOR TUNING CONSULTATION AND WARRANTY CONFIRMATION OR INSPECTION RETURN AUTHORIZATION. PARTS RETURNED WITHOUT AUTHORIZATION NUMBERS WILL BE REFUSED AND RETURNED FREIGHT COLLECT.

PARTS RETURNED FOR INSPECTION AND WARRANTY CONSIDERATION AND NOT FOUND TO BE DEFECTIVE WILL BE CHARGED A MINIMUM INSPECTION AND ADJUSTMENT CHARGE OF $35.00 AND RETURNED FREIGHT COLLECT.

Contact REDLINE WEBER at 1 800 733 2277 ex 7457 Monday thru Friday 8:00 to 5:00 Pacific Standard Time

Non warranty Tech support is on a fee for services basis with minimum charge of 35.00 per problem resolution. With tech support calibration and tuning parts will be available at discount pricing as well as access to technical support documents and mailings.







E-Mail sales@carbs.net




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Unread 08-03-2011, 12:20 AM   #7
mcmud
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1983 CJ8 
 
Join Date: May 2008
Location: N.E. Alabama
Posts: 2,650
The information 4.7stroker passes along is very good....for a Weber built 32/36DGEV.

That said, using the guide is wise for the sake of procedure however the best screw settings are anyones guess.

The Solex design labeled as a Weber DGEC is a contract built carb. It is not built to the genuine Weber standards, nor by a Weber manufacturer. Since it is built in so many countries, by different manufacturers, I doubt that the internals on any two are alike.

Prime example: Find a standard guide for tuning one, the reason it doesn't exist is that the internal bore holes (enrichment and port) are wherever they are, the only person knowing is the one who drilled them.

In attempts to help those that purchased this carb I've found that if the speed screw is set to 1-1/8 turn in after contact (while the engine is hot, the choke plate held, maintained open and after opening/closing the throttle) and the mix screw set somewhere between 1-1/2 to 3 turns out will be near enough to be of help.

The mix screw setting will depend in great part to the idle jet sizes...there again its anyones guess. If you find trouble with obtaining a smooth idle (with the mix screw) then a look into which sizes are set would be wise.

When you say that the mixture screw has little effect.... and the initial is set to 9*BTDC with the advance tube disconnected and 12ish with it connected is indicative of having the speed screw too far inward, exposing both the enrichment hole as well as the 'S' vacuum port.

Then after making adjustment move the vacuum advance tube back to the manifold source that it was connected onto. It is my honest opinion that the instruction to move the advance tube to a ported source is a MAJOR FAULT in the nutter guides, your distributor was designed to use manifold vacuum...not ported.

Following 4.7stroker's suggestion to purchase the pre computer distributor should be considered.

Here is another link that will help guide you through having it (or if you prefer your existing one) perform to a standard that is as good as it gets.
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