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Unread 04-17-2013, 09:03 AM   #1
blucat88
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Intermittent stalling... At idle, coast and stop

Having an issue with my 89 YJ. Ran horrible until I put in a new Weber 2 bbl carb and Holley Pressure Regulator. Good friend and mechanic assisted with the install. Runs great, but when you are coasting down to stop or sometimes when stopped, you get a "miss" where the tach dips to zero and sometimes kills the motor. It's almost as though there is a momentary interruption in fuel supply - like a bubble in the line? Only other issue is it bogs a little bit when you stomp the throttle; but it straightens right out. My moment to post here was when the mechanic put his head on the steering wheel and said "I'm out of ideas. It's just so intermittent" lol. I'm pretty new to the game, so any help would be greatly appreciated. Thanks!!!
~Blu~
BTW - New mechanical fuel pump, cylinders all have excellent pressure, fuel filter is clear so I can see that there seems to be plenty of fuel; Plugs, wires and rotor button all new.


Last edited by blucat88; 04-17-2013 at 12:23 PM.. Reason: clarification
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Unread 04-22-2013, 09:27 PM   #2
blucat88
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Update: New carb running somewhat rich and (lightly) fouling plugs. Driving hard and fast on highway seems to clear the issue up for a while until I drive in city traffic for a while, then problems return. Noticed that sometimes the filter is fully charged with gas, and sometimes it barely has anything in it and is blowing bubbles inside... Thinking of going to an electric fuel pump and running some smaller jets. (currently running 160s).
wp_20130420_002.jpg  
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Unread 04-23-2013, 05:49 AM   #3
cruiser54
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Don't rule out that troublesome ignition box. They do weird things. If it were me, that 4.2 would get an HEI distributor.
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Unread 04-23-2013, 11:31 PM   #4
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Don't rule out that troublesome ignition box. They do weird things. If it were me, that 4.2 would get an HEI distributor.
I would check the fuel pressure from the pump with a vaccume and fuel pressure tester could be a weak fuel pump or dirty fuel filters and if its running rich adjust your air fuel mixture with the two screws on the carb
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Unread 04-24-2013, 06:53 AM   #5
cruiser54
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Concentrate on the jetting. How many turns out are your mixture screws?
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Unread 04-24-2013, 06:53 PM   #6
TheU
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I had the same problem try the crankshaft sensor. My jeep had been doing that for a long time and monday it finally would not start had the dealer look it over and that is what it was.
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Unread 04-24-2013, 08:14 PM   #7
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Quote:
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I had the same problem try the crankshaft sensor. My jeep had been doing that for a long time and monday it finally would not start had the dealer look it over and that is what it was.
Seppin he don't have one of dose there things.......
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Unread 04-26-2013, 09:11 AM   #8
blucat88
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The Carb doesn't appear to have mixture screws... Which I figure is just my ignorance, however - There are only two screws besides the idle set screw and they don't appear to be adjustable. If you loosen them, they are LOOSE and feel like they will just vibrate out. (New Weber Carb = WK550-38 38 DGES-JEEP 4.2 Ltr. 250ci). It has a pair of 160 jets in it and the exhaust smells like it's probably rich; so the plan is to try a couple of smaller sizes to see if it helps. I put a timing light on it and it is doing exactly what it is supposed to be doing - (it is hitting dead on 9 and backing off appropriately upon acceleration). The ignition box could certainly be an issue, because the whole vehicle had straw / mud / silt / nests, etc. in every void space I opened. (It had been stored in an auto shop for several years before I picked it up). I hate to even consider electronics, because it's all voodoo to me. lol
Thanks for the tips. I'll update as I uncover new info. This gives me some good leads!
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Unread 04-26-2013, 02:21 PM   #9
cruiser54
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The timing is not supposed to back off. It's supposed to ADVANCE.

Don't mean to throw a monkey wrench in the workd at this point, but how about replacing your distributor with an HEI conversion? Makes a lot of difference and eliminates that pesky Ford ignition system. Any pics of the carb?
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Unread 04-26-2013, 03:39 PM   #10
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Here's something for you to follow.

http://www.jeepforum.com/forum/f19/h.../#post15352845
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Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

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Unread 04-26-2013, 04:38 PM   #11
Speedymcracer01
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Quote:
Originally Posted by blucat88 View Post
Having an issue with my 89 YJ. Ran horrible until I put in a new Weber 2 bbl carb and Holley Pressure Regulator. Good friend and mechanic assisted with the install. Runs great, but when you are coasting down to stop or sometimes when stopped, you get a "miss" where the tach dips to zero and sometimes kills the motor. It's almost as though there is a momentary interruption in fuel supply - like a bubble in the line? Only other issue is it bogs a little bit when you stomp the throttle; but it straightens right out. My moment to post here was when the mechanic put his head on the steering wheel and said "I'm out of ideas. It's just so intermittent" lol. I'm pretty new to the game, so any help would be greatly appreciated. Thanks!!!
~Blu~
BTW - New mechanical fuel pump, cylinders all have excellent pressure, fuel filter is clear so I can see that there seems to be plenty of fuel; Plugs, wires and rotor button all new.
My truck did that coasting down hills,sitting at red lights just about any time i took it out of gear moments later you would hear and feel engine start shuddering like it was about to run out of gas or something then it would die if i did not raise the rpms i replaced my throttle body gasket and it quit doing it. Have you checked for any vacuum leaks or maybe a gasket that could let in unwanted air flow?
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Unread 04-26-2013, 05:52 PM   #12
cruiser54
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Quote:
Originally Posted by Speedymcracer01 View Post
My truck did that coasting down hills,sitting at red lights just about any time i took it out of gear moments later you would hear and feel engine start shuddering like it was about to run out of gas or something then it would die if i did not raise the rpms i replaced my throttle body gasket and it quit doing it. Have you checked for any vacuum leaks or maybe a gasket that could let in unwanted air flow?
His is not fuel injected. Has no throttle body.
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Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

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Unread 04-26-2013, 06:12 PM   #13
Speedymcracer01
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Quote:
Originally Posted by cruiser54 View Post

His is not fuel injected. Has no throttle body.
yes i know im not formiliar with carbs..does the carb not have a
Gasket like a throttle body does that could possibly be leaking pulling extra air in threw the bottom of the carb?thats what i was thinking when i said that
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Unread 04-26-2013, 06:44 PM   #14
blucat88
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Here is the pic from Weber's Website. The distributor idea makes sense to me based on how it's acting. A spark interruption would make perfect sense based on the way it cuts out so intermittently. As for the gaskets - all new and snug as can be. Cruiser: forgive my ignorance, but are you referring to an electronic conversion kit, or upgrade to a new / hotter distributor? thanks again for all the input!
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Unread 04-26-2013, 08:15 PM   #15
cruiser54
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Summit Racing sells complete HEI distributors that eliminate the Dura-Spark ignition system. It will run WAY better. Then, we can sort out any carb issues if there are any.
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Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
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