Need help with High idle after mc2100 swap - JeepForum.com

 
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post #1 of 12 Old 09-16-2013, 10:41 PM Thread Starter
c5wagner
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Need help with High idle after mc2100 swap

I recently put a mc2100 with 1.08 venturi and size 48 jets in my 1989 jeep wrangler with the amc 258cid motor, but the thing will not idle below 1200 rpms. I checked all the vacuum lines and there are no leaks, the manifold to adapter and the adapter to carb all showed no signs of leaks with carb cleaner either. I plugged up the choke hole at the carb base and got a manual choke and that didn't change anything. My timing is set at 8*. Has anyone else had anything like this?

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post #2 of 12 Old 09-16-2013, 11:05 PM
booboowv77
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How about your fast idle screw?

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post #3 of 12 Old 09-16-2013, 11:07 PM Thread Starter
c5wagner
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Quote:
Originally Posted by booboowv77 View Post
How about your fast idle screw?
removed it trying to get the idle down, no effect

1989 Base YJ,4.2l,DIY GM TBI,AX15,Np231 SYE/6 pin planetary/Wide chain, D30 ARB, 8.8 ARB 4.56
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post #4 of 12 Old 09-16-2013, 11:30 PM
booboowv77
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Does your throttle cable have slack in it or is it tight? Something is stopping it from going the whole way down.

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post #5 of 12 Old 09-16-2013, 11:36 PM
booboowv77
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Also try backing off your fuel mixture, mine is only 3/4 of a turn out but I am running a 1.14 venturi.

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89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
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post #6 of 12 Old 09-16-2013, 11:38 PM Thread Starter
c5wagner
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I've gone in and out with minor changes made. I think I'm going to try decreasing my jet size from 48 to 46

1989 Base YJ,4.2l,DIY GM TBI,AX15,Np231 SYE/6 pin planetary/Wide chain, D30 ARB, 8.8 ARB 4.56
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post #7 of 12 Old 09-16-2013, 11:40 PM
booboowv77
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I'm running 48's in mine and I get a nice normal 750 rpm and lower with no problems

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89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
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post #8 of 12 Old 09-16-2013, 11:45 PM Thread Starter
c5wagner
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I have a feeling I have a terrible vacuum leak somewhere but I can't find it. I think it's vacuum because the plugs show lean conditions

1989 Base YJ,4.2l,DIY GM TBI,AX15,Np231 SYE/6 pin planetary/Wide chain, D30 ARB, 8.8 ARB 4.56
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post #9 of 12 Old 09-16-2013, 11:47 PM
booboowv77
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spray carb cleaner around the base and see if it changes anything. Alot of people problems at the gasket.

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89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
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post #10 of 12 Old 09-16-2013, 11:50 PM Thread Starter
c5wagner
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Quote:
Originally Posted by booboowv77 View Post
spray carb cleaner around the base and see if it changes anything. Alot of people problems at the gasket.
I did that already, I checked all mounting surfaces to make sure they're not warped, replaced gaskets and no leaks still. This is the first thing I have been truly lost as what to do with my jeep

1989 Base YJ,4.2l,DIY GM TBI,AX15,Np231 SYE/6 pin planetary/Wide chain, D30 ARB, 8.8 ARB 4.56
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post #11 of 12 Old 09-17-2013, 12:03 AM
booboowv77
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I still think something is hold it up, I would double check that first. I have not had this problem but hopefully some one will chime in in the morning that might have other possible solutions.

GOOGLE IS YOUR FRIEND!!!
Just my toy!
89 YJ, Fresh 4.0, ax15, SOA w/410's, and about a million other things! :)
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post #12 of 12 Old 09-17-2013, 01:04 AM Thread Starter
c5wagner
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Quote:
Originally Posted by booboowv77 View Post
I still think something is hold it up, I would double check that first. I have not had this problem but hopefully some one will chime in in the morning that might have other possible solutions.
You were right, I very thoroughly checked all the throttle shaft parts and found a slight bend on the throttle connector causing a bind, it was very hard to see without VERY close inspection.

1989 Base YJ,4.2l,DIY GM TBI,AX15,Np231 SYE/6 pin planetary/Wide chain, D30 ARB, 8.8 ARB 4.56
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