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post #76 of 151 Old 02-28-2014, 01:49 PM
86cj74.2L
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Yes, you need more tension on your choke.

Rotate the choke housing until it closes fully and slightly more for some spring tension.

Turn your idle mixture screws in until you see a 1/8 of shoulder showing on average. Fully warmed up.

After which you will hear a slight surge at idle and that's the mixture going rich and lean. Its normal in closed loop. In fact on Grammys CJ when it doesn't have that slight surge its my indication something is wrong.

You may discover your idle screws end up being around 2 1/2 turns out. My approach for lean best idle is no with a vacuum gauge but the idle drop method.

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post #77 of 151 Old 03-01-2014, 12:31 PM Thread Starter
moto450r
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SUCCESS!!!
With the cold start that is....


Thanks for all the help!!!

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post #78 of 151 Old 03-01-2014, 12:54 PM Thread Starter
moto450r
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I adjusted the idle mixture screws in until the stepper pin "step" is about 1/8" extended, they were fully retracted. Set the Curb Idle to 680 RPM and now the engine RPM hunts +50ish RPM then back to 680. The stepper pins are moving all the while.
Also, the RPM was steady @ 680 before I adjusted the idle mixture screws.


Could it be this??? (see picture)

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post #79 of 151 Old 03-01-2014, 01:09 PM
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Are BOTH of the idle mix screws adjusted the exact same?
Those be the tubes we drill out........
LG

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post #80 of 151 Old 03-01-2014, 01:19 PM Thread Starter
moto450r
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Quote:
Originally Posted by LumpyGrits View Post
Are BOTH of the idle mix screws adjusted the exact same?
Those be the tubes we drill out........
LG
Yes

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post #81 of 151 Old 03-01-2014, 02:51 PM
86cj74.2L
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With the stepper maintaining a 14.7:1 AF ratio by moving the pins in and out it will slightly surge.

It is how it works with the MCU controlling the mixture.

Don't hunt for a problem that isn't there.

You got it. Now enjoy it.
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post #82 of 151 Old 03-01-2014, 04:04 PM
LumpyGrits
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Hmmmm. Mine is 100% OEM and passes Ca, Smog.
I have zero 'surge'.
Me thinks there is something else like a slight vac leak.
Make sure ALL of your manifold bolts are tight. Ck all the vac. hoses.
LG

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post #83 of 151 Old 03-01-2014, 04:51 PM
86cj74.2L
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Quote:
Originally Posted by LumpyGrits
Hmmmm. Mine is 100% OEM and passes Ca, Smog. I have zero 'surge'. Me thinks there is something else like a slight vac leak. Make sure ALL of your manifold bolts are tight. Ck all the vac. hoses. LG
Is your stepper moving in and out at idle?

Don't say you have zero surge until you also say its moving all the time too.

The guy on adventures under the hood mentions the surge as a byproduct of the stepper operation also.

Think about it. The idle mixture is always going rich-lean-rich-lean how can it not surge.
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post #84 of 151 Old 03-01-2014, 05:11 PM
LumpyGrits
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YES-the pins be mov'n.
My idle is as smooth as can be, at just under 700rpm using a secondary tach to do all of my settings. The OEM tack(like most Jeep gauges)is not that close.
I do run the MSD setup, and without 'Hammer's' dizzy upgrade.
There is no noticeable surge. My idle will vary at most, 20-25 rpm per my known tach. over a couple minutes of time.
LG

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post #85 of 151 Old 03-01-2014, 06:18 PM
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I never measured Grammys surge. But its there enough you can hear it with the pins moving in and out around their center position. It has no tach. I have a tach I have alligator clips on that I hook up and set on battery when I do things I need a tach for.

After reading about the surge back in the early 2000's on Adventures Under The Hood I now use it as a indication that the Puter is operating.

When I don't here it, its time to look for a bad switch or what not........
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post #86 of 151 Old 03-01-2014, 07:15 PM
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Quote:
Originally Posted by 86cj74.2L View Post
I never measured Grammys surge. But its there enough you can hear it with the pins moving in and out around their center position. It has no tach. I have a tach I have alligator clips on that I hook up and set on battery when I do things I need a tach for.

After reading about the surge back in the early 2000's on Adventures Under The Hood I now use it as a indication that the Puter is operating.

When I don't here it, its time to look for a bad switch or what not........
Hav'n to deal with this maze of SMOG crap on my Ca. model CJ-7 since 1985.
I do feel that if the surge is noticeable. There is somedangthing that ain't work'n 'rite'.

I can't depend on my hearing as I'm deaf in my right ear, and 60% lost of high freq in my left.
LG

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post #87 of 151 Old 03-01-2014, 07:41 PM Thread Starter
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Quote:
Originally Posted by 86cj74.2L View Post
I never measured Grammys surge. But its there enough you can hear it with the pins moving in and out around their center position. It has no tach. I have a tach I have alligator clips on that I hook up and set on battery when I do things I need a tach for.

After reading about the surge back in the early 2000's on Adventures Under The Hood I now use it as a indication that the Puter is operating.

When I don't here it, its time to look for a bad switch or what not........
Cool.
I'm going to let it ride for a few days as it is, only because I have another observation that may be related in a round-a-bout way......

After I set the idle mixture screws, I decided to watch the main discharge nozzles to see how the FA mixture was coming out of them. I have been wondering what affect (or is it 'effect') the wrong size metering rods, and the jet I resized, was having. What I saw was odd or may be not. At about 1500 rpm the inboard nozzle/venturi had a good bit of fuel coming out of it but the outboard nozzle/venturi had very little, in comparison. At about 2000-2500 they both seem to be flowing at the same rate. I wonder if there is less flow on the outboard nozzle/venturi because its location is further out on the manifold or ??????

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post #88 of 151 Old 03-01-2014, 07:57 PM
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Wonder if you see the same deal, when the engine is under load?
How's it run'n?
LG

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post #89 of 151 Old 03-04-2014, 12:19 PM Thread Starter
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Trying to get a video uploaded of the engine start this morning. No joy on the upload . As soon as I get it to load I'll post a link. It was a good start this morning @ 60*F. Not "cold" by any stretch, but it did well.

Idle speed is still not falling back to the 680 RPM consistently. Over the past few days of driving, the RPMs stay up around 900-1000. This higher idle seems to be a symptom of something else but it has been happening ever since I adjusted the Idle mixture screws from 3 1/2 turns to 2 1/2.

As a reminder:
- 3 1/2 turns gave me the Highest Vacuum as the RPMs began to drop. The stepper motor pins are pulled all the way back, indicating a rich mixture.

- 2 1/2 turns gave me a lower vacuum but the Stepper Motor pins are extended about an 1/8" and move in/out.

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post #90 of 151 Old 03-04-2014, 01:05 PM
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Is the choke plate held Firmly open when the engine has warmed up? I have seen a worn or out of adjustment choke spring cause symptoms like that.

Mike
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