Vapor lock? - JeepForum.com
 
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post #1 of 6 Old 03-28-2004, 09:45 AM Thread Starter
OKJeepin
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Vapor lock?

A buddy of mine has an '88 YJ, 258, Weber carb, stock fuel pump, and we had a full tank of gas.
Yesterday we were up on a very hard core trail, Jeep was at a 30 degree or so angle on a long rocky climb , just made it to a three step ledge and it died. It would start but not run for more than 2-3 seconds. We pulled the line going into the filter, and no gas while cranking, after 20-30 minutes of playing with it, it finally started and ran just fine, I think it might have been vapor lock but am not for sure. He's never had this problem before even in 110 degree weater tho, anybody have any ideas?

Jeff


1974 CJ-5 (Rockcrawler)
2001 Grand Cherokee Laredo (Curbcrawler)
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post #2 of 6 Old 03-28-2004, 06:02 PM
sstaurus
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Well, as far as I know vapor lock is when the gas evaporates in the bowl and/or gas line before it can get to the engine (because it is so hot out).

More likely in your case it's just that carbs don't work on inclines, some are worse than others. If the bowl emptied out or something it would be hard to start...? The only solution is upgrading to EFI, or not driving on inclines heheh.

Just ideas
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post #3 of 6 Old 03-28-2004, 08:26 PM
CanukYJ
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EFI is the best but not the cheapest, I've seen holley adds stating they make carbs for wranglers made for 'extreme angles' so it may be a chaper idea.

My jeep has only ever killed 3 things, a cat, a deer, and my wallet. What's the problem officer?

1992 Red YJ. Lifted, locked, and loaded with beer (Disclaimer: This doesn't mean said driver endorses drinking and driving, please enjoy alcohol responsibly and do not operate any vehicle of any kind, thank you....)

Thanks to the price of gas here ($4.25 a gal) I just bought a mountain bike, 0" of lift, 0" of travel, MT's, locked rear axle, oh yeah, it's the sh#$.
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post #4 of 6 Old 03-28-2004, 09:26 PM
Tshark299
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I have a Weber and it runs like absolute crap on any kind of uphill incline. I can get it to stall if I brake hard enough in reverse. Even on slight inclines it will idle very rough and eventually stall on a semi-moderate incline.

Anyone else with a Weber have these characteristics? Mine also cranks forever before it starts when the engine is warm. It starts a little quicker if i hold the gas down while cranking, but often it stalls if I let go of the gas too soon after that. Starts instantly when the engine is cold though, when the fast idle cam is engaged.

When it does finally fire when warm and it doesn't stall, it idles very roughly at about 300-400 rpm for 5-10 seconds and gradually rises to the normal 700 rpm idle. Then after that it runs fine... Maybe these two things are related?

'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 #5 of 6 Old 06-07-2010, 12:25 PM
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I have kind of the same problem with mine. If I park on an incline for any reason my 1990 YJ won't start worth a crap. Sometimes I have to push it to another spot, and let it sit for a minute before I can get it to crank. I have noticed that unscrewing the gas cap to release the pressure helps in getting it up and going faster.

I have a stock carb, and plan on doing a rebuild very soon, I already bought the kit, just need the time. The real reason for doing the rebuild though is because of the general starting problem. I have to give this old jeep some throttle to start, EVERY TIME. I bought the jeep about three months ago and this is my first jeep. The throttle was set way high when sold to me and this is the reason why. Also, after the first start from sitting for a while, it will die when I put it in reverse, or drive sometimes. I have to restart, let it sit a couple seconds, then try again.

Any suggestions, besides a carb kit anyone?

Chase
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post #6 of 6 Old 06-07-2010, 04:26 PM
Tshark299
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Quote:
Originally Posted by chaserYJ1990 View Post
I have kind of the same problem with mine. If I park on an incline for any reason my 1990 YJ won't start worth a crap. Sometimes I have to push it to another spot, and let it sit for a minute before I can get it to crank. I have noticed that unscrewing the gas cap to release the pressure helps in getting it up and going faster.

I have a stock carb, and plan on doing a rebuild very soon, I already bought the kit, just need the time. The real reason for doing the rebuild though is because of the general starting problem. I have to give this old jeep some throttle to start, EVERY TIME. I bought the jeep about three months ago and this is my first jeep. The throttle was set way high when sold to me and this is the reason why. Also, after the first start from sitting for a while, it will die when I put it in reverse, or drive sometimes. I have to restart, let it sit a couple seconds, then try again.

Any suggestions, besides a carb kit anyone?

Chase
Sounds like the typical problem with the Carter BBD carb. You can try rebuilding it, or cleaning out/drilling out the idle tubes, but in the long run you might be happier swapping to a Weber 32/36 or Motorcraft 2100 carb. Both seem to be a more reliable design than the stock carb.

As for my problem from my last post in this thread 6 years ago, it turns out I needed a fuel pressure regulator to reduce the fuel pressure to the Weber to about 3psi. After that it ran alot better on inclines and started easier when warm

'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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