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Old 07-30-2019, 06:49 PM
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'97 SE seems to be vapor locking recently.

Runs fine for close to an hour. Then it dies when I have to take my foot off the gas. Will not start until it has rested awhile. The longer it rests the longer it will run for before dying again.

Pumping the gas peddle has kept it running a couple times. That works less than half the time.

I am also running a higher than normal concentration of fuel injector cleaner. Used a bottle meant for a full tank - maybe 20 gallons - with about 9 gallons of gas. But it "vapor locked" a few days ago - before trying the fuel injector cleaner.

Never had vapor lock before. But it seems to be what I've heard people describing with their vapor lock problems.

I get a faulty fuel pump vibe as well. Just a hunch there. The fuel pump has about 15,000 miles on it and is about 7-8 years old. Been replaced once.

Losing the engine on a tough 4WD trail could have some very poor consequences. Had to winch to get the Jeep off the trail. It would start - then die. Etc. Then ran fine for an hour after cooling for a few hours. Quit twice in 1 1/2 hour ride home. Disconcerting.

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Old 07-30-2019, 07:19 PM   #2
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Sounds like a vent line for the gas tank or emissions system got pinched. Did this happen before the fuel pump was replaced?

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Old 07-31-2019, 09:08 AM   #3
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Any codes?
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Old 07-31-2019, 10:07 AM   #4
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Check all vacuum hoses and determine if a leak.
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Old 07-31-2019, 10:30 AM   #5
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Have you checked your fuel pressure?
Sounds more like a bad fuel pump to me.
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Old 08-01-2019, 07:44 AM   #6
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I would start with checking the fuel pressure as suggested by crallcars. It should be around 49psi. I'm assuming you have a '97 2.5cyl which aren't known to have vapor lock issues.
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Old 08-01-2019, 11:43 AM   #7
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When my YJ had vapor lock it was a cracked exhaust manifold
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Old 08-02-2019, 11:07 AM   #8
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It shouldn't vapor lock because it has a fuel pressure regulator and a return line to the tank. Return line could be pinched, maybe a bad regulator. Start with fuel pressure if that's good start looking at the return line and regulator.
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Old 08-02-2019, 06:48 PM
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Originally Posted by Kota7x View Post
Sounds like a vent line for the gas tank or emissions system got pinched. Did this happen before the fuel pump was replaced?
The fuel pump was replaces many years ago. Last year I replaced a part of the fuel line assembly around the gas tank. It had started leaking very badly and I was very lucky to have looked under the Jeep and noticed while I still had enough fuel to get down the trail to where the JL's etc could be found.

Perhaps there is a problem in that area now. Perhaps something got knocked loose or? The problem with dying just started very, very recently.

Think I can check my fuel pressure pretty soon. Keep thinking the fuel pump is a good suspect. Bought a Bosch last time as I recall. Not sure what I might get this time.
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Old 08-02-2019, 08:43 PM   #10
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Codes??....
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Old 08-04-2019, 03:10 PM
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Codes??....
Need my code thingie for that - I am in the absolute boondocks. Jeep has not seen a city slicker in years. Don't like driving it when it is prone to dying either.

Come to think of it though - right before it started dying I finished a hike and found my fuel cap had been opened. Thought that was quite odd. Small chance that it got vandalized - maybe 10% chance or so.
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Old 08-04-2019, 03:14 PM
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I would start with checking the fuel pressure as suggested by crallcars. It should be around 49psi. I'm assuming you have a '97 2.5cyl which aren't known to have vapor lock issues.
Sounds good - except that I need a Walbro Bundy fitting to check fuel pressure unless I just cut the line - which I'd like to avoid. Took hours to identify the fitting I needed.

The fitting should allow for checking fuel pressure and hopefully this case will be laid to rest.
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Old 08-04-2019, 05:37 PM   #13
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I don't remember if the 97 will display the codes on the odometer with the key on off on off on trick.(within 5 seconds, not starting, just clicking hey to on position)...
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Old 08-07-2019, 10:13 AM   #14
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Been battling a similar issue on my 2006 - 4 cylinder too. It runs great for about an hour and then acts like it's out of fuel. Let it sit for an hour or two and fires back up and runs perfectly.
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Old 08-10-2019, 09:22 AM
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Been battling a similar issue on my 2006 - 4 cylinder too. It runs great for about an hour and then acts like it's out of fuel. Let it sit for an hour or two and fires back up and runs perfectly.
We should talk in 1-2 weeks. I should have my fuel pressure checked by then. Waiting for a Walbro Bundy fitting.

I sure do miss being able to do everything with wrenches and screwdrivers.
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Old 08-11-2019, 08:02 AM   #16
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Going to drop my tank today. Did it again Friday. Picked it up yesterday morning and struggled to run initially but then cleared up and ran fine home. Definitely acts like a fuel problem. Didn’t have the fuel pressure gauge with me though. However it did have normal pressure the week prior when I checked it. I think either the pump is getting hot or there is something in the tank. Only seems to do it after an hour of running and when the tank is down around a quarter or less.
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Old 08-11-2019, 08:10 AM   #17
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I don't remember if the 97 will display the codes on the odometer with the key on off on off on trick.(within 5 seconds, not starting, just clicking hey to on position)...
Yes 97's do display codes on the odometer.
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Old 08-11-2019, 02:08 PM   #18
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May have found my issue. This came out while I was emptying the tank.
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Old 08-11-2019, 03:32 PM   #19
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May have found my issue. This came out while I was emptying the tank.
Is that some plastic or gasoline varnish? Enough to really plug up the pickup.
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Old 08-11-2019, 08:08 PM   #20
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It was thin plastic. Had to order the ring removal tool for the fuel pump so hopefully I’ll know more tomorrow.
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Old 08-11-2019, 09:16 PM   #21
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How in the heck did that get in there? Seeks like only a deliberate stuffing would do that. And even then, hard to get something down the snout. Strange.
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Old 08-11-2019, 09:19 PM   #22
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Looks like sausage casing lol, someone stuck a summer sausage stick in your tank
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Old 08-12-2019, 07:52 AM
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May have found my issue. This came out while I was emptying the tank.
Someone unscrewed my gas cap while I was hiking. Later on that day - it quit running after an hour. It has quit many times since that hike.

Thinking I need to increase the sabotage odds quite a bit. Oh well - Dropping the tank isn't too terrible.
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Old 08-12-2019, 11:08 AM   #24
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Someone unscrewed my gas cap while I was hiking. Later on that day - it quit running after an hour. It has quit many times since that hike.

Thinking I need to increase the sabotage odds quite a bit. Oh well - Dropping the tank isn't too terrible.
It's not too bad. I didn't even drain the tank. Had about 7-8 gallons in it. Once everything was disconnected, placed a floor jack under it and removed the skid plate nuts. Only thing I could disconnect was the fuel pump electrical, but there's enough slack in it. Can be dropped in less than an hour.

My only issue, is mine has the metal retaining ring for the fuel pump, so I had to buy the special spanner wrench to get it out.
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Old 08-12-2019, 08:35 PM   #25
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My only issue, is mine has the metal retaining ring for the fuel pump, so I had to buy the special spanner wrench to get it out.
Would you post a link to that? Thanks.
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Old 08-14-2019, 08:59 AM   #26
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Would you post a link to that? Thanks.
Got it on Amazon. Worked perfect.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
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Old 08-14-2019, 09:02 AM   #27
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Oh, and I found the rest of the plastic. It was a ziploc bag, plus a bunch of paper, some black tape and an old fuel pump gasket. All of this was in the tank. Crazy...
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Old 08-14-2019, 12:29 PM   #28
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Oh, and I found the rest of the plastic. It was a ziploc bag, plus a bunch of paper, some black tape and an old fuel pump gasket. All of this was in the tank. Crazy...
Bizarre.
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Old 08-15-2019, 09:13 AM   #29
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I can only assume you have your new locking gas cap "on the way"

I also have a Dodge diesel pick-up. I found a couple gallons of water in the fuel tank, that was just after I figured out my injector pump went south. Bosch injector pumps wholesale are $2000 and about an hour to install.
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Old 08-24-2019, 08:28 PM
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Got my Walbro Bundy fitting to hook up the pressure gauge to fuel system. Reading 23 psi coming into the injectors. I suspect that is why it doesn't start with the snap that it used to.

But it runs with that pressure. Why did it just start dying? Why is it ok after cooling off for awhile? The longer the better.

This thread may be dead. I may need to make a new thread regarding ramifications of 23psi of fuel pressure.

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