Speaking of emisions

[Ayres]

I have a couple questions on working towards fixing my truck for those emissions failures I had a couple weeks ago. I tested the coil an spark wires and several other easy items. I started working towards the harder items like carb settings and timing. I have to say I am beginning to think the carb is a bit over my head. I have a 4 barrel motorcraft and there is just so many settings or at least a bit more than I have seen on the 2 barrel holley I rebuilt. I think I could do it with a better book but the one I am using the pictures are a bit old.

Anyway...

My thoughts are to take it in to a shop and let them deal with it. I called a shop that a friend said was tructworthy and they quited $67 just to look at it. Then they would know what needs to be fixed. I am thinking about going that route at least this time because the registration late penalties are stacking up and if I fail emissions again it will cost something like $12 for the retest.

I am pretty sure my timing is off and I think I now know how to fix my choke setting problem. But I do not think I know how to get in and fix any mixture problems without pulling the carb off.

anyone have any advice or ideas of where else to go from here?

Thank you all

Brian Ayres
1978 Cherokee
360 Engine

------------------
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[joe]

Brian, you say you "think" he timing is off? If so...time it. The carb is the "last" thing you mess with on a full tune up. Make sure all your plug wires, cap, rotor, timing blah blah is within spec. If you try to tune out an ignition problem by adjusting the carb you're just going to end up with one really out of whack carb and a poor running truck with no chance ever to a pass smog test.

------------------
Regards,
-joe
63 2-dr Wag, 73 J-4000, 82 CJ-8

[Ayres]

That sounds about right. I know the timing is a bit off because it seems the distributor is a bit loose. The only problem I see with timing it is trying to figure out where to shine the light in comparison to the marks. They are pretty deep in there.

[mhoffor]

First clean the marks with a rag and some cleaner, solvent, or WD40. Take chalk, paint, or a crayon and mark the grove in the damper, and the 5BTDC mark. Now when you start the moter hold the light so you can see the marks the best (the variation at different angles is so little it doesent matter).

Another idea is to get a POBox in Yuma Or Flag at a contract mail office so you have a street adress and register it their.

------------------
Mike Hoff
74 J10
360 Edelbrock Carb
TH400 w/shift kit
Headman Headers 3" pipes w/flomasters
Spring over front 8" net lift
Shackel flip w/2 1/2 steel blocks rear 7" net lift

[nograin]

Do you know what you failed for? Otherwise fix what you can see is obvious and go for a retest. Otherwise your grasping at straws.
If they tell you exactly what and where (its a roller test I assume?) it is failing, thats well worth a $12 retest IMO.

For example, if it fails idle (ah the good ol days) for NOx being at 1200 ppm or whatever they are measuring at, then you can figure your either too lean at idle or too far advanced. Also when you take it back you'll know if you made an improvement and how much closer or furhter you are from your goal.

------------------
360 auto select
body by beer (PO)
carries wood inside
no "wood" outside

[Ayres]

I failed NOx and CO2 during the roller speed test. I think they take it up to 40mph'ish and sniff the tailpipe. I did not fail by that much. I can get the exact numbers off the sheet when I go home tonight.

------------------
Brian Ayres
1978 Cherokee
The FSJ with a Full Size Bumper
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[nograin]

OK. Let us know.
If thats right, my GUESS is that is that it is not the carb, but an emissions system that needs adjustment. If there was no emmisions controls, going richer will decrease the NO2s , but will increase the CO. With nothing further to go on, I'ld check the EGR valve, the CTO for it, and maybe the the air pump valves, especially if the first one is hooked to a vaccum control of some sort.

At least you know its OK at idle, so the idle settings got to be close, both timing and carb.

[Ayres]

Wow thank you for all the suggestions I will get the actual numbers out and see what is the cause. I know after the first time I went for emissions I failed all numbers. I then found out that the stupid idiot (previous owner) had disconnected the smog pump and of course it froze. heck they failed me for just not having that hooked up.

Honestly I would like to have my truck actually run somewhat clean not just for emissions but for my own piece of mind. Kinda sappy but oh well we each have our flaws.



------------------
Brian Ayres
1978 Cherokee
The FSJ with a Full Size Bumper
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[Ayres]

Ok so I was wrong here is the actuall readings and test results.


Hydro Carbons (HC)
Idle: Standard 350, Reading 385, FAIL
Loaded: Standard 350, Reading 176, PASS

Carbon Monoxide (CO)
Idle: Standard 4.00, Reading 7.26, FAIL
Loaded: Standard 3.00, Reading 2.92, PASS

This was the results from my second Emissions test. During the first test I also failed the Carbon Monoxide Loaded by a full point. Then I replaced the smog pump and poof, I squeaked by.

One note on that smog pump is that I am pretty sure that I need to replace the canister and the air injection manifolds that take the air from the pump and inject it into the exhaust manifolds. These parts are dealer only so I have not gotten to it yet. They are installed but the check valves in the manifolds are going bad but I do not think that will help me in emissions. I believe all the problem is that air is let backwards from the exhaust to the pump when the pump is not putting out any air.

So the idle stuff fails. I have been trying to familiarize myself with the carb and all the set screws and levers. But before doing to much I will see what everyone here has to say. Thank you all so much for all the help and advice. I have been a bit frustrated about this.




------------------
Brian Ayres
1978 Cherokee
The FSJ with a Full Size Bumper
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[nograin]

If its only at idle, then try to concentrate on things that only effect idle, and have little or no effect elsewhere.

No NO2 test?

If both HC and CO is high at idle, then you are running to rich at idle. My first guess then would be to see how much leaner the idle circuits will go and still run OK.

[Ayres]

I am really not tryign to sound dumb or anything but I have to say adjusting my old 2 barrel holley on a inline six is soo much easier than adjusting anything on this 4 barrel Motorcraft on my 360.

A couple questions if I can run this thread out some more. Please exuse the lingo I do not always know the correct names for everything *smile*.

On the carb there is the small lever attached to the accelerator cable from the pedal inside the cab.That lever has several 'stops' attached to it. One stop touches the anti-dieseling solenoid and the other touches a stop with a set screw (some idle speed I assume). This is all on the left side of the carb. This side of the carb I think I undersand pretty well. The right side of the carb is where it gets confusing. There is an automatic (?) choke and many levers and bars and set screws. The choke seems to control max and mins of vane settings. Where as the lever that is tied to the bar that goes through the carb has a set screw that touches the plastic piece that has the indentations for the different settings of idle speed depending on temperature. (I think)

So I guess my confusion with all this is what parts of the carb need to be adjusted to help my idle speed mixture? I understand completely if it is too difficult to explain but I have asked all my friends and they all tell me to just take it in and pay the $67.50 so I thought I would ask you all.

Hopefully I made some sense through this.

------------------
Brian Ayres
1978 Cherokee
The FSJ with a Full Size Bumper
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[nograin]

Hey, believe me, I was in your boat when I got interested in cars...

Now, I am not familiar with your particular carb, but they are all similar, especially the Holleys and Motocrafts.

The throttle cable attaches through that lever to the throttle. Thats the plate on the shaft down the venturis. Yup. The notches are for fast(cold), and slow (warmed up) idle speed settings. The solonoid pulls away when the engine is turned off - making sure the throttle plate closes completely so there is no run-on.

The top butterfly plate is your choke. It restricts the airflow, so makes the mixture richer. (Technical it strengthens the pull or vacuum signal down stream on the fuel).

Controlling the choke, and idle settings is proabably a bimetal coil. The other stuff you see, I am guessing is the controlls for the back two (secondary) venturies. They either open when the front ones get far enough open, or when they get enough open AND there is a strong internal vacuum signal in which case there is a diagphram device linked to the back throttle shafts.

Interesting, but what you are looking for is the idle mixture screws. There should be one on each side of the front of the carb. Usually they are needle valves in the fuel passages, but sometimes they are in the air passage. Got to find someone who knows that carb, to know which they are.

PS. Sometimes mfc. hid the screws under caps..."factory set"

Hope that helps a little, and hope someone who knows that carb can tell you more about its particulars.

I found the HP book on Holley carbs terrific in helping me understand how these things work.

[Ayres]

Well I have the Technical Service Manual for my jeep so it has some good information so with that and what you are saying I should be able to find out what to do. One point that I am curious about is that would the choke not releasing also make the mixture too rich?

I also have a related problem that might also lead me to a solution. It seems at certain times the engine never kicks down fully from the at least middle idle speed. It might be my imagination but it always seemed to be during the summer when it would be too hot. I know there is something screwy because after starting the car and leaving it running for about 20 min I went out gunned it a bit and the engine still did not kick down to the lowest setting. After taking the air cleaner assembly off I could kick the choke side of the throttle down by hand and then the engine would kick down to a nice idle speed.

If I work this out in my head... If the engine never idles down and the choke is still engaged at normal temperatures and I go for emissions testing the choke would still be engaged therefore cutting the amount of air and making the fuel mixture too rich?

I have been tinkering around with the choke at cold temps and full temperatures to see what the vanes are set at. I think the vanes never open up fully at hot temperatures. You are correct nograin that the choke is a little bimetal coil housed in a small encasement on the right side.

Anyway I will look around at books and the carb to see what I can find out and maybe make some adjustments to choke and mixture then go in for a retest.

Thank you all again for all the help. This really does reduce my frustration.


------------------
Brian Ayres
1978 Cherokee
The FSJ with a Full Size Bumper
www.inficad.com/~sungodra/fsj/FSJ.html (http://www.inficad.com/~sungodra/fsj/FSJ.html)

[nograin]

Glad I could be of some help.

You may be on to the real culprit. I didn't think of that because I forgot there is a choke pull-off that might have opened the choke up when they were bringing the car up to 40 mph. (I haven't had an automatic choke for a while) I was thinking the choke plate remained at the same setting independent of averything else but temperature..and that is probably not so.

[smithhl]

Just move to Tennesse! I'm twenty two and my dad has lived in Tn even longer. We have never had to take any of our vehcles over the years to any kind of inspection. My engine runs rich, no smog equipment, no catatilytic converters, and puffs white smoke with each gear change. The only thing that might get you pulled over is if you only were running exhaust manifolds or headers, and thats only because of the noise it would produce!

------------------
short and sweet, but hard to beat