87 4.2L sometimes hard to start - JeepForum.com

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post #1 of 33 Old 07-30-2013, 05:05 AM Thread Starter
ufvj217
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87 4.2L sometimes hard to start

So my 88 YJ I bought about 2 months ago is great except for every once and a while it's hard to start. Usually after I drive it to one place, park go inside do whatever then come back out, it takes a few cranks of the key to start. And when it finally starts sometimes it'll blow a little white smoke out of the exhaust. Other than that it doesn't smoke overheat etc. The guy I bought it from said sometimes the choke sticks??

Its all stock as far as I know except a motorcraft carb.

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post #2 of 33 Old 07-30-2013, 05:36 AM
Old4X
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Normal for a carb sitting on the exhaust manifold in hot weather.

418 miles on 19 gallons of gas. Can't beat the BBD !
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post #3 of 33 Old 07-30-2013, 05:40 AM Thread Starter
ufvj217
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Should I pump the gas at all? Not sure if all carbs are like that but my dads 81 vette I pump the gas when starting after sitting. Once its started it'll start right up after that even when its warm.
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post #4 of 33 Old 07-30-2013, 05:52 AM
Rproject
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As a practice, I put the pedal to the floor ONE time, then back up, to set the choke, before I start mine. Every time. Creates a habit and seems to help her kick over cleanly. Even when warm.

I'm also running the MC2150.

1996 White ZJ
1987 Maroon YJ (sideways build)
1996 Forest Green XJ

The "sideways" build thread: http://www.jeepforum.com/forum/f22/r...hread-2164793/
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post #5 of 33 Old 07-30-2013, 05:54 AM Thread Starter
ufvj217
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Ill try that out. Could it be possible that the choke sticks like the PO told me?

And the smoke is normal?
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post #6 of 33 Old 07-30-2013, 06:06 AM
Rproject
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Quote:
Originally Posted by ufvj217 View Post
Ill try that out. Could it be possible that the choke sticks like the PO told me?

And the smoke is normal?
White smoke is typically the indicator of anti-freeze in the exhaust system. Either that or your Jeep just elected a new Pope.

As for the one pump chump start. By setting the choke before you start it, you could be avoiding a stuck choke issue. It's worth a shot.

1996 White ZJ
1987 Maroon YJ (sideways build)
1996 Forest Green XJ

The "sideways" build thread: http://www.jeepforum.com/forum/f22/r...hread-2164793/
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post #7 of 33 Old 07-30-2013, 06:16 AM Thread Starter
ufvj217
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Hmm..hopefully no antifreeze in the exhaust. ..
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post #8 of 33 Old 07-30-2013, 07:23 AM
jokerchief462
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Depending on outside temp almost all vehicles produce a little white smoke after start up and you can see some water dripping from the exhaust tip. It's condensation from hearing the air and it goes away fairly quick unless it is really cold out.

Are you sure that's not what your seeing???

89YJ 2.5L TBI, AX-5, NP231 SYE, Ford 8.8, Yukon Grizzly, Tom Woods Shaft, 33" BFG T/As, 4" lift, Warn VR10000s.

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post #9 of 33 Old 07-30-2013, 07:42 AM Thread Starter
ufvj217
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Ill take a video next time I drive it which will probably be later this evening.
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post #10 of 33 Old 07-30-2013, 08:13 AM
jimhill
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Quote:
Originally Posted by Rproject

White smoke is typically the indicator of anti-freeze in the exhaust system. Either that or your Jeep just elected a new Pope.

As for the one pump chump start. By setting the choke before you start it, you could be avoiding a stuck choke issue. It's worth a shot.
That was a good one lol
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post #11 of 33 Old 07-30-2013, 08:42 AM
bpounds
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When the engine is cold, I push the throttle halfway and release once, and she starts better than at any other time.

When the engine is warm, I hit the starter and then progressively give more throttle as it cranks, and it usually kicks over. If it cranks a little more than expected, I'll give the throttle a couple of pumps to get some fuel moving. I've not yet seen this engine/carb flood. If it isn't starting, it needs some pumps. I'm running a fresh rebuild of the OEM Carter BBD.

You just have to find the combination that works for your setup. Those of us who were around before fuel injection took this stuff in stride. No more just reaching through the window and turning the key. You're going to be a little more interactive with it and you have to learn her preferences.
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post #12 of 33 Old 07-30-2013, 08:48 AM
jbrown73
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I had the same issue with mine (Weber 32/36) with hard starting after shutting down and letting her sit for a little bit. I tried all kinds of starting scenarios and found that if she had been off for 8+ hours, then I would set the choke by one full pedal press. Once warmed up/driven and shut back down for any shorter duration, I do not touch the gas pedal and she cranks up after 5-10 seconds. Every time I tried to manipulate the gas pedal while trying to crank when the engine is warmed up resulted in flooding.

Old4x has an excellent point with his comment and that condition contributed to some of my issues. Vapor lock is causing your hard starting due to the nature of the carb sitting directly above the exhaust manifold. With the engine at operating temp and then shut down, everything is becoming heat soaked and the fuel is actually boiling in the carb. Next time you shut her down after driving a while, wait about 5 minutes and lift the hood......I'll bet you will hear the fuel boiling in the carb bowl. I actually started a thread on this a few weeks back. Search 'fuel boiling in carb'.
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post #13 of 33 Old 07-30-2013, 09:50 AM
bpounds
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Quote:
Originally Posted by jbrown73 View Post
...I do not touch the gas pedal and she cranks up after 5-10 seconds...
That's a loooong crank in my book.
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post #14 of 33 Old 07-30-2013, 09:53 AM
Rproject
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^ Beat me to it

1996 White ZJ
1987 Maroon YJ (sideways build)
1996 Forest Green XJ

The "sideways" build thread: http://www.jeepforum.com/forum/f22/r...hread-2164793/
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post #15 of 33 Old 07-30-2013, 10:10 AM
jbrown73
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It was an estimate.....more like 5 seconds. I was in a hurry to type since I'm at work.
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