Engine hesitation when I mash the gas - JeepForum.com
 
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post #1 of 7 Old 11-11-2004, 03:34 PM Thread Starter
farmboy1976
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1987 YJ Wrangler 
 
Join Date: Jan 2003
Location: Winona, MN
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Engine hesitation when I mash the gas

I am having a little issue with my 6cyl 1987, when I slowly give it gas it reacts just fine but if I get on in quick it spudders (hesitates) for a second and then takes off. I recently replaced the carb but had the same issue with the old one. It is a stock carter carb on it that has been pressure tested and idles well at 700 rpm's, so I don't believe it's a mixture problem.

Anyone have any suggestions on what I can do?

Thanks.


Farmboy1976 (1987 Wrangler)
3.5 inch 4wd Suspension lift, 33 x12.5 BF's
Replaces items since purchase: Tires, Top, Radiator, Starter, Slave Cylinder(twice), Clutch Master Cylinder, Lots of hoses, Ring Gear, Clutch, Rebuilt Starter, Water Temp Gauge, MC2150 carb, nutter bypass, Electric choke, TFI Distributor, replaced power steering box, Smittybilt front seats
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post #2 of 7 Old 11-11-2004, 04:29 PM
MattB
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sounds to me like it's the accelerator pump..
could also be one of the check balls in the carb not in the proper position.

I just rebuilt a carb today from an '89 that was having the same problem (well, one of the handfull of problems was a stumble when you hit the gas). turned out to be the accelerator pump seal was messed up and one of the check balls was improperly seated.

also check the carb bowls for water. don't know if that will cause it, but this one had about 1/8" of water in the bottom.
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post #3 of 7 Old 11-29-2004, 08:18 PM
boulderz
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Did you ever figure out what was doing this? I am having the Exact same problem.

Thanks,

Mike
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post #4 of 7 Old 11-30-2004, 11:00 AM
Yoink
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Fuel System

Quote:
Originally Posted by boulderz
Did you ever figure out what was doing this? I am having the Exact same problem.

Thanks,

Mike
I had a similar problem with a fuel pump/fuel filter. A replacement solved the problem and gave me way more go too. Of course I'm running FI'ed not Carbed sooo it might be be different depending on your setup.

'95 YJ SE - I6 4.0L, 2" BDS, 1" Shackle Lift, 2.5" BL, 31X10.50 A/T's, Herculined (Work In Progress)

AIM - XDemiG0DX42
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post #5 of 7 Old 11-30-2004, 11:50 AM
Tshark299
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My new Weber does the same thing to an extent. I was told it was normal.

'87 YJ Laredo - 4.0L, AX-15, NP231, 4.10s: 3.5" BDS, 31" Muds

'95 XJ - Donated drive train to the YJ, Parted out the rest

'51 CJ-3A - Buick 225 V6: Painless Wiring Harness, Warn Overdrive & Hubs, 2" Lift, 31" Muds
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post #6 of 7 Old 11-30-2004, 03:04 PM
boulderz
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I don't think it's normal. If the accelerator is slowly pressed, it is fine. But if you get on it it will sputter, sometimes backfire and then stall. Not good for wheeling. Last night I cleaned idle pickup tubes and it still does it after. No vacuum leaks.

Anyone replaced or adjusted the throttle position sensor or accelerator pump? I don't even know where the TPS is...
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post #7 of 7 Old 12-01-2004, 01:39 PM
Tshark299
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Quote:
But if you get on it it will sputter, sometimes backfire and then stall.
Oh wow, mines not nearly that bad. Mine just has a slight stumble when the second barrel kicks in. Nevermind then!

'87 YJ Laredo - 4.0L, AX-15, NP231, 4.10s: 3.5" BDS, 31" Muds

'95 XJ - Donated drive train to the YJ, Parted out the rest

'51 CJ-3A - Buick 225 V6: Painless Wiring Harness, Warn Overdrive & Hubs, 2" Lift, 31" Muds
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