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Unread 05-05-2012, 07:19 PM   #1
kovic
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How to get a 258 running smooth with a weber

Hi guys.

1983 CJ 5, fresh inline 6 258. I've had a Weber 32/36 on it for a couple years now, rebuilt a few months ago. It ran pretty good at idle, and drove nicely, but if it was accelerated quickly it would bog (when the secondary opens) I thought that was normal, until I read into it...

uptillnow has helped me tremendously through email for the past week, with his help i adjusted the float to 18mm, redid the adapter gaskets (vacuum leak), and adjust the linkage among other things.

I have the carb back on.....and it idles worse than it did before, and on the road after heavy acceleration it stalled at a stop on me...it hasn't did that since the carter.

It also seems to go up and down idle, or when i rev it sometimes it almost dies , and it does die if I open the secondary for to long.

I have the timing adjusted to 8 degrees, the mixture is best when out around 1 1/2 turns, and I have zero vacuum with 1 1/4ish turns on the idle screw.

The jets are that of a weber, nothing has been changed....i did purchase a primary jet of .80, had it on, and it wasn't to bad, but from reading its sounds like I should be able to get it smooth with the .75.

Up to this point I feel i need all the ideas I can get, so please pitch in....

I'm not even sure how smooth a 258 can get, but I'm sure it could be smoother than what i have it now.

Thanks guys

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Unread 05-07-2012, 02:55 PM   #2
mcmud
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Quote:
1983 CJ 5, fresh inline 6 258. I've had a Weber 32/36 on it for a couple years now, rebuilt a few months ago. It ran pretty good at idle, and drove nicely, but if it was accelerated quickly it would bog (when the secondary opens) I thought that was normal, until I read into it...

uptillnow has helped me tremendously through email for the past week, with his help i adjusted the float to 18mm, redid the adapter gaskets (vacuum leak), and adjust the linkage among other things.

I have the carb back on.....and it idles worse than it did before, and on the road after heavy acceleration it stalled at a stop on me...it hasn't did that since the carter.

It also seems to go up and down idle, or when i rev it sometimes it almost dies , and it does die if I open the secondary for to long.

I have the timing adjusted to 8 degrees, the mixture is best when out around 1 1/2 turns, and I have zero vacuum with 1 1/4ish turns on the idle screw.
Are you able to open the throttle plate to 1-1/2 turns in with the speed screw and still read zero vacuum at the "S" port nipple, that one which is farthest away from the mixture screw.

Another way to put all of that, open the plate to the maximum that you still read zero vacuum at that nipple, and then work with the mixture screw.

Start with it set to 3 to 3-1/2 turns out and then turn it inward at 1/4 turn intervals while allowing ample time between each adjustment for the engine reaction to each one...at the onset expect these tweaks to have a very subtle effect.. they will be there none-the-less.
Find that point that the mixture screw has caused a rather continuous lean hiccup then back it out to that point which the hiccup (misfire) has all but disappeared. One occurring at every 8-10 seconds is the lean best setting and that is a good place to start.

These adjustments are to be made while the engine is hot, the oiled air filter set and the vacuum advance ("S" port) nipple plugged.

Once adjusted to these settings and you still have difficulty pegging the pedal without receiving a pop at the carb for that effort you might need a closer look for air leaks?

If you are relying on ported vacuum for spark advance consider bumping it up to 10* and then work with the screws.


Welcome to JF.
Reads as though a good guy sent you.

Quote:
The jets are that of a weber, nothing has been changed....i did purchase a primary jet of .80, had it on, and it wasn't to bad, but from reading its sounds like I should be able to get it smooth with the .75.

Up to this point I feel i need all the ideas I can get, so please pitch in....

I'm not even sure how smooth a 258 can get, but I'm sure it could be smoother than what i have it now.

Thanks guys
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Unread 05-07-2012, 05:28 PM   #3
86cj74.2L
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They are notorious for vacuum leaks at the intake manifold.
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Unread 05-07-2012, 06:09 PM   #4
Chuckles0227
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Mcmud is a great guy, he helped me out immensely when i was setting up my weber and it ran very well for a while. After i went to an off road park it wouldn't idle at all unless i turned the idle adjustment up to 1100 rpm. I did have the 34 and have no experience with the 32/36 but the 34 was designed by weber then produced by solex, after that trip to the park i tossed it and put a mc 2100 on and have never looked back. the difference between my 34 and mc2100 is like night and day, i get better gas millage and it is a lot better off road.

If you want to stick with the weber then listen to mcmud he will help you get it set up correctly. i personally do not want to have to mess with the carb every few months which is why i put the 2100 on my 258.

just my
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Unread 05-07-2012, 06:41 PM   #5
Matt1981CJ7
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Quote:
Originally Posted by Chuckles0227 View Post
Mcmud is a great guy, he helped me out immensely when i was setting up my weber and it ran very well for a while. After i went to an off road park it wouldn't idle at all unless i turned the idle adjustment up to 1100 rpm. I did have the 34 and have no experience with the 32/36 but the 34 was designed by weber then produced by solex, after that trip to the park i tossed it and put a mc 2100 on and have never looked back. the difference between my 34 and mc2100 is like night and day, i get better gas millage and it is a lot better off road.

If you want to stick with the weber then listen to mcmud he will help you get it set up correctly. i personally do not want to have to mess with the carb every few months which is why i put the 2100 on my 258.

just my
Your 34 was a Weber clone with serious quality control issues. It was not indicative of a true "Made in Spain" Weber.

I'm not surprised you like the 2100 better, but that's not an accurate comparison to a real Weber, IMO.

Matt
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Unread 05-07-2012, 08:49 PM   #6
kovic
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Hey mcmud, thanks for the response.

The farthest I could open the throttle plate was 1 1/4, after that it would read vacuum, very little, but still.

I have the carb out right now, I am going to head out and follow the redline guidelines to tune it to a T (again) and see if I get and results.

Now, do I do anything with the speed screw, behind the choke housing? Right now it gets caught on the lever it goes against and causes the throttle not to close all the way, easily fixed by opening the choke and tapping the throttle then is pops back, but how do i stop that?

The 'S' port, is another issue, it goes to my TCO, i think its called that... mine is 2 ported, and my distributor goes to the brass nozzle thing (sorry) that sticks out of the intake under the carb, out towards the driver side fender. I need to have the 'S' port plugged while doing the tuning?

I dont know if my vacuum lines are set up correctly...still learning. Also when it was on there was white axhaust coming out.... not sure what that means

Also, i have not did the Team rush upgrade, and nuttering wont help me as my jeep has no on board computer.

Also, hiccups in the exhaust, every 8 to 10 seconds is where i want it?

Anyways, thanks, and ill update you how it goes tonight for me.

kov
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Unread 05-07-2012, 09:35 PM   #7
mcmud
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That fast idle speed screw can be a real nuisance even when set in a wide range of positions... none quite right.
We should work with that one once you have a smooth and steady idle going on while the mixture screw is nearer to spec.
For the time being back the fast idle screw out until it causes no interference to the throttle plate closing.

The "S" port feeding the CTO ...what is it controlling?

The white smoke sounds eerie. Is it stinking rich and stammering or a rather sweet smelling water vapor?

The little hiccups can be seen with the eye, felt through the screw driver as well as heard through the pipe.

Disconnect the vacuum advance tube and plug the source while adjusting the baseline settings.
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Unread 05-07-2012, 11:50 PM   #8
kovic
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Ok, I have it running better than it was. Heres what I did:
- Took carb off, took cap off doubles checked float, 18mm
- clean what i could with carb cleaner.
- Adjusted the screw that opens and closes the secondary, 1/6 turn in after touching.
- put back on motor
- set idle in at 1 1/2, mixture at 2 turns out
- warmed motor up, pumped gas until warm enough to stay running.
- eventually stayed running, rough, 400-450 rpms
- put mixture to 1 3/4 best i could get it.
- adjusted timing, was at 8, tryed 12 degrees, had a consistent pop. rpms got to 550

Then this part, not sure if its ok.... but what i noticed was when I unplugged the vacuum advance it would rev higher, and when i plugged it in it would lower again, so I changed to putting the advance to the 'S' port, where there is zero vacuum so it wouldnt change, and what it used to go to, the bronze thing that sticks out of intake manifold under the carb, i plugged.

The hose that used to go to the S port is now just open.. not sure what to do with it.

After that the engine has a fairly smooth, no popping idle of 500-550 ish.

I think my vacuum set up has issues... not sure how it should go.

So I actually got the zero vac at the S port with 1 1/2 turns in, mixture is 1 3/4 out, and i have a fairly steady vacuum of 19 hg out of that bronze thing from the intake.

Im surprised its running this good, could maybe be better, but its a smooth idle,

How do I get the idle up, if I cant turn the idle screw in anymore than 1 1/2?

Also, the CTO was connected to the S port and the EGR, no idea what any of the vacuum stuff controls.....

Thanks!

Last edited by kovic; 05-08-2012 at 12:48 AM..
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Unread 05-08-2012, 04:05 AM   #9
Matt1981CJ7
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The "bronze thing" is the manifold vacuum nipple.

If you set the timing with the distributer attached to that nipple, then your initial timing is severely retarded, right now. Timing should be set with the vac advance disconnected and plugged.

Take some pics of your engine compartment, and we'll sleuth thru the vacuum systems. Most likely that's a big part of your problems.

Matt
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Unread 05-08-2012, 06:33 AM   #10
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Kovic, you should fill out your profile so forum members can see what you have and make answering your questions more accurate.

As far as vacuum lines for your particular year vehicle, it all depends on what is removed from PO (Previous Owner) or is it still OEM from the factory. Are you still using the more favorable OEM air cleaner assembly or one of the small elements that came with the Weber carb? Either way, vacuum routing after a Weber carb is installed can have some people scratching their heads trying to determine what can go and what needs to stay for for engine and some for the emissions to function. What do you have left as far as emissions related apparatuses? EGR, Charcoal Canister, PCV,?

As Matt1981CJ7 has said, take some pictures of your engine compartment and post them here.
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Unread 05-08-2012, 06:35 AM   #11
mcmud
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Kovic, why are you starting with the mixture screw at 2 turns out... you may have over-run the sweet spot from the onset.
Starting the process with that screw at 3 to 3-1/2 pretty much assures that you find the lean best idle inside of that.
I would not expect to read that you find the best quality idle at 1-3/4 turns...what size is your primary idle jet?
You mention that the initial timing was at 8. You tried 12 and had a consistent pop. Did you attempt 10*.....where is it now?
It is normal to gain rpm with the manifold nipple open it should be plugged when not in service.
It isn't normal to see a reduction in rpm when you reconnect the vacuum advance tube to that source.
Is the vacuum advance actuator arm being drawn toward the dist. vacuum canister as you reconnect that tube?
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Unread 05-08-2012, 10:50 AM   #12
kovic
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Thanks guys. I started with the mixture screw at 2 out because thats what the redline tuning guide called for. 1 3/4 is where is seemed to run the smoothest. Primary jet is .75. I did try 10*, but was not better than 12*.

Normally the manifold nipple went to the distributor, i would have it off to set the timing, but when i put it back on the "actuator arm would pull forward and change the idle because there id always vacuum at the manifold nipple, thats why I put the advance to the S port, so there was zero vacuum, then the actuator arm would pull forward when the gas was hit.

When I unplugged right at the manifold nipple the engine dies, but if I have the whole slightly covered, making it a smaller opening the engine raced a little. but right now I just have it plugged.

How do I put pictures up?

Thanks

kov
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Unread 05-08-2012, 11:17 AM   #13
kovic
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Ok figured it out.









Ill try to explain also how it is.

Vacuum advance to manifold nipple.
S port to TCO
EGR to TCO
Hole in back of valve cover goes to air cleaner
PCV goes to port on front of adapter plates
float bowl vent goes to charcol cannister, think thats what it is, lower firewall on driver side
The cannister has 4 port, 2 are blocked, one goes to gas take, other to float bowl vent.

This is how it was.

thanks

Last edited by kovic; 05-08-2012 at 01:06 PM..
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Unread 05-08-2012, 11:43 AM   #14
kovic
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Well went out this morning and started it, wouldn't stay running on its own until it was warm...and barely....
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Unread 05-08-2012, 12:31 PM   #15
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Kovic,

It's difficult to tell from your tiny pics, but your description indicates the fuel filter is not vented. It should be a 1-in 2-out type filter. The vent should be installed at 12 o'clock and connect to the canister.

Also, I think I see an extra fuel filter down by the distributer. That shouldn't be there.

You may also consider getting rid of the pressure regulator. Yes, I know Weber recommends them, but they aren't necessary on a 258 with the correct pump and filter, and they can cause more problems than they eliminate.

Otherwise, your plumbing doesn't look too bad, from what I can tell. I've seen much worse.

Matt
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