International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tire Kickin' > General FSJ Tech

Thread Tools Search this Thread Display Modes
Old 07-16-2009, 03:47 PM
westcoastflea westcoastflea is offline
Join Date: Jan 25, 2004
Location: maine
Posts: 229
fuel pump stalling issues

have read other posts about fuel pump vapor lock issues but this problem seems a bit different

my jeep starts fine first thing every day. it has so far run just fine for any length of time as long as i dont shut if off.

tuesday i ran errands started fine in the morning ran about 15 minutes when i got back in it started fine ran it 60 seconds it stalled

took about an hour to find starter fluid came back and used the starter fluid twice on the second try it started up

the next day started cold just fine ran an errand about 15 minutes on the highway spent an hour in the store came out started up just fine but again huffed out in about 60 seconds.

starter fluid wouldnt start it. tried numerous times.

took off gas cap tried to start it using starter fluid no start

took off fuel line before fuel filter tried to start it no gas came out of the line

walked to gas station got gas put alot in carb didnt start. put alot more in carb and it started and ran just fine, sat about 4 hours then started just fine again.

started fine this morning when i did the fuel volume test.

so basically i seem to have an issue with getting gas either from the fuel tank to the pump or from the pump to the filter, NOT SURE WHICH when the vehicle has been runniing and it is shut off restarted and then driven about 60 seconds.

i checked my fuel volume when cold and i get at least 1 pint of fuel in about 10 seconds which is very good

fuel pressure tester is way too expensive to buy to test the pressure on the pump.

so while it may be vapor lock or a bad mechanical pump im leaning towards trying to fix all problems with one solution
electrical fuel pump

wondering if this will solve all issues, vapor lock, fuel lines heating up,a failing mechanical pump
etc etc etc??

seems to be the least expensive, easiest way to go?

so before doing this id like some feedback as to whether any of my assumptions are correct?

also need to know how to hook up the electrical wiring for the fuel pump?

can i just install new metal fuel lines with the new pump then connnect the new fuel lines right before the mechanical pump with gas type rubber hose? my fuel lines look rusted i dont see any leaks but figure i should replace, i do i have to try to remove the old lines? or can i just run new ones along side the old ones?

oh yes and how do i get the large nut type thing on top of the gas tank off?
ive done it in the past its taken forever and i end up ruining the piece to get it off.

appreciate any advice or help i know the post is long but its kind of a strange problem

thanks guys


started wednesday morning just fine. ran it on the highway about 15 minutes stopped came back out about an hour later started just fine ran another 60 seconds and died like it was out of gas. used starter fluid numerous times wouldnt run.
Reply With Quote
Old 07-16-2009, 05:07 PM
Chevelleguy's Avatar
Chevelleguy Chevelleguy is offline
Join Date: Jul 20, 2003
Location: Hughes Springs, TX
Posts: 5,572
Sounds like vapor lock due to heat soak. While sitting after you have run it for a while, the heat from the engine and exhaust manifold soak into the carb and the fuel line that is on the left frame rail. You could put a clear plastic inline fuel filter before the pump so that you can see what is going on when it acts up. If my theory is correct the filter will be empty when it dies. Insulating the fuel lines fixed my problem when I was running a carb and was cheap. Now I have TBI and have rerouted the fuel lines completely.
David "If all else fails, read the instructions."
83 Wag Lt,BJ's 6"lift,360/727/Pinned229,D44/trac-lok,AMC20/lock-right,35/12.50 Baja MTZ,Pro-Jection EFI.
10$ NP229 fix
Reply With Quote
Old 07-16-2009, 05:11 PM
Jeep Craze's Avatar
Jeep Craze Jeep Craze is offline
Bleedin' Gasoline
Join Date: Sep 14, 2001
Location: Kempton,Pennsylvania
Posts: 1,508
I had the same EXACT symtoms. Turned out to be the bypass on the fuel filter Was clogged. Now here is the kicker,it wasn't dirt. When the fuel filter wasmade (napa gold) they used too muchglue on the paper filter and it was clogged aparently from day 1. While it is running pull the bypass hose off the filter and see if u get fuel. If u do then blow through the line to the tank to make sure that's not clogged. If there is still a problem get an electric pump
91 GW 360/727 Black cherry metallic, maroon interior, 100% restored with some mods.
1985 J20, Chevy 350/700r4/jeep208 3" rough country lift kit
83 CJ8 Scrambler-Wifes Toy MERCEDES TURBO DIESEL /4spd, 4" lift, 35" tires
2014 Polaris RZR 570- PRP Bench Seats. 3 -5 point harness,2" lift kit, roof, windshield
Reply With Quote
Old 07-18-2009, 11:00 AM
westcoastflea westcoastflea is offline
Join Date: Jan 25, 2004
Location: maine
Posts: 229
thanks so much for the replies i guess my only question now is how do you hook up the electric supply for the fuel pump?

thanks again
Reply With Quote
Old 07-18-2009, 02:24 PM
grand_wag_85's Avatar
grand_wag_85 grand_wag_85 is offline
Murphy's Law Poster Child
Join Date: Dec 03, 2003
Posts: 10,713
You can run straight to the battery or thru a relay but the safest way would be a relay switched to key on power with a collision switch from a Ford.

There is a pump most parts stores carry(Part number B2000 IIRC) that runs around $35. Pressure is set for 5.5PSI, comes with mounting bracket and grounds thru that.
You know it's bad when your car's on the EPA's 10 most wanted list!

'82 J10
'88 GW
'77 J10 Golden Eagle 401

Reply With Quote
Old 07-18-2009, 06:51 PM
andy d andy d is offline
Shade Tree Shaman
Join Date: May 06, 2000
Location: Marshfield,MA
Posts: 7,205
check out the fuel pickup and the return lines, a clogged fuel sock is a lot cheaper than rigging an electric fuel pump. In Maine vapor lock shouldn't be an issue. The jeep ran fine for 20 yrs with a mechanical pump. why re-invent the wheel?
\'88 gwag,pure stock
Reply With Quote
Old 07-18-2009, 07:34 PM
FSJ Guy FSJ Guy is offline
Join Date: Mar 20, 2005
Location: Colorado
Posts: 10,061
Originally Posted by andy d
check out the fuel pickup and the return lines, a clogged fuel sock is a lot cheaper than rigging an electric fuel pump. In Maine vapor lock shouldn't be an issue. The jeep ran fine for 20 yrs with a mechanical pump. why re-invent the wheel?

Because the wheel is using outdated technology.

I'd check your fuel filters and install an electric fuel pump anyway.
Ethan Brady
1987 Grand Wagoneer, slightly longer than stock.

Don't mess with me. I once killed a living hinge.
Reply With Quote
Old 07-19-2009, 08:21 AM
scotty1998's Avatar
scotty1998 scotty1998 is offline
Master Mechanic
Join Date: Apr 21, 2008
Location: Watkins Glen, NY
Posts: 912
I know I'll get oil thrown at me or something but I have a problem with chalking symptoms up like you describe to "vapor lock." I don't doubt the science behind it and can see how it could happen but there are a host of simple things that come to mind to check first.

Clogged fuel sock. Expose that large hex nut on the tank and take a blunt edge on a screw driver and then carefully strike it to loosen the nut. Lefty loosey. It should come loose with not problem. Just remember to vacuum out the nut and clean off the top of the fuel tank before opening. No need to insert more dirt in the tank.

Bad mechanical pump. No further instruction on this one. It either works or it doesn't. I've been thinking about going electrical too but just haven't wanted to spend the money on it yet.

Bad carb fuel pump. There's a little hole on the bottom of the plate for the pump. If fuel is leaking out, that could be your problem. You might just want to check to see if that plate is loose and/or leaking too.

And, here's a stretch. In theory, I would think that a dirty air filter on your vapor canister could contribute to poor fuel pickup if the system is air tight and working properly, especially with a full tank.

Leaky power valve?

Clogged fuel line or clogged return line.

Fuel system could be sucking air somewhere. Check for checked or seeping fuel lines.
1987 Jeep Grand Wagoneer
Stock Everything
AMC 360, 2-BBL Motorcraft

Last edited by scotty1998 : 07-19-2009 at 08:24 AM.
Reply With Quote
Old 07-21-2009, 08:40 AM
westcoastflea westcoastflea is offline
Join Date: Jan 25, 2004
Location: maine
Posts: 229
thanks for all the replies

checked my fuel filter the vapor hose is supposed to be attached at the 12:00 position i believe and it wasnt. so i changed it to the correct position, while doing so i noticed fuel coming from the filter so blew on hose and didnt feel like it was obstructed.

also reattached the large plastic thing that connects from the air filter cover to the front of the jeep assume this makes things run cooler?

also wondering how you clean the filter on the vapor cannister?

have driven several times but am so afraid of being stuck again im limiting the jeep to straight shot drives where i stay for a few hours before trying to drive again.

am going to check out a few other things like whether the butterfly thingie that is in the exhaust pipe is in the correct position as it seems that might cause more heat in engine as well

am going to research that on this site to see if i find answers

am also finding another issue of battery being drained overnight which has just started happening as well as the issue of interior lights staying on which has also just started happening. i dont believe the two are related since i took out all the bulbs one night but still found the battery drained the next morning.
so if i cant find answers will be posting for that as well
so am going to go at this slowly i suppose before changing to electric fuel pump once again appreciate all the answers guys

thanks again
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -6. The time now is 12:43 PM.

Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
corner corner