JeepingDan

How do I prevent vapor lock in my fuel lines? I never had this problem before until today. I got off the highway parked in a big hot parking lot under the sun went in the store came out 10 min. later and it started and sputtered and stalled so I cranked it a couple times with no response and figured instead of cranking it till my face turns blue how bout I open the hood and figure out whats the malfunction here. First thing I did was poke the schrader valve on the fuel rail and nothing but hot air came out at a high pressure so I'm like AH HA! so I turned the key in the ON position and purged all the air out and then I was on my way again.

MasterShakeXJ

i get it out on the trail sometimes, it's cylinder 3 i believe. you can install some hood vents, which i cant speak to personally b/c i dont have them. of stack some small washers on the hinges in the back of the hood to raise it up a little bit.

but what i usually do, is when i stop on the trail, i just open the hood to let it cool. sometimes i'll leave it running for a couple mins so the fans keep goin or just turn it off and let it cool. or when your wheeling it, and everyone stops, just leave it running.

c-loss

This is gonna sound real redneck but I have heard allot of the old guys that my dad used to hang out with take wooden clothes pins and put them all down the fuel rail. I never said its something I would/have done but I have heard it works to help disapate the heat. I WILL STATE THIS ONE MORE TIME FOR THE DUMB *** WHO WANTS TO START FLAMING. IT IS WHAT THE OLD GUYS I USED TO TALK TO SAID TO DO.

98 JeepJeep

it sounds to me like your check ball in the fuel pump isnt holding pressure any more dumping the fuel back into the tank when the key isnt on. My cherokee does the same. normally i have to cycle the key a few times and wait. You can replace the pump assy or install a inline check valve.

JeepingDan

Thanks I think I might have a idea here. the thing is I don't want to cut any holes in the hood cause I want the stock look and it's lined up to the body perfectly. clothes pins? that's kinda out there but you never now till you try. or I can just deal with it and purge the fuel rail when I have the problem. Thanks for the opinions they help and I'll be looking for more.

98 JeepJeep

FYI opening the schrader valve on a hot motor isnt the best idea.

JeepingDan

Thats a good lead Thanks.I have to do the same thing cycle the key on off on off. And yea I know opening the valve on a hot motor isint a good idea. But thanks I'm gonna look at that.

bradpoorman

Vapor lock i didnt even think of that! I am having almost the same exact problem with mine. If I leave mine idle for about 10 minutes it starts running like *** and missing real bad and if I dont start moving again it shuts off, and when I do go under the hood there is a ridiculous amount of air in the line. I noticed changing the fuel pressure regulator helped too so I stocked up on those at the boneyard.

JeepingDan

Well with the weather getting warm again same spot "Home Depot" got vapor lock again I already replaced the pump and the fuel filter and regulator last year. any idea's? the heat shield is there on the manifold. You think the fiberglass mat under the hood could be helping the heat stay in there? I'm about to rip the thing out and maybe research hood vents that don't look stupid. What do you guys think? btw this is my stock XJ Trying to keep it factory like.

NAMBA860

clothes pins do work the wood will absorb the heat out of the metal fuel line. beleive it or not it does work. also you can put a little transmission fluid in with the gas it lowers the boiling point of the fuel.

ol"blue

Lowering the boiling point would aggravate the condition. Then there is the smoke from the burning trans fluid issue. I wouldn't try this "remedy".

JeepingDan

Yea. I was iffy about that one

JeepingDan

bump

woodnut_jeep

I am having the same problem did you ever get your's fixed?

Bustedback

Vapor lock is not an issue with a high pressure fuel injected fuel system. If it were a carb system, then vapor lock might be a problem, but not really.