Sitting on the side of the interstate

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Dec 15, 2008
Northeast, Alabama
i need help.

i am a college student and have had a couple problems and not enough money.

the 82 fj40 runs fine on local commutes, but breaks down on the interstate on long hauls. any hints, i cant afford any more mechanic's labor hours.

all fluids fine
no overheating shown on gauge
rebuilt engine (15-20,000 miles on rebuilt)
31" all terrain tires
55mph and under fine
till about 65-70 ish (for about 30min-2hours), then cuts, loses power
idles for about 30min to an hour after lose power to move fj40 down road
new gas tank
fuel system cleaned/checked
carb cleaned/checked

it has happend twice, same exact thing, mech. checked it both times and worked on it and said all looked ok.

could the "house m.d." of tech please diagnose

thanks for the reply mike,

i have a new fuel filter, and it was clean at the last breakdown.

i searched coil and got a ba-zillion results, so i dont know which you are refering to (sorry i am a glorified rookie)

My thought would be fuel. Do you have electric or mechanical pump?

Do you have access to a fuel pressure gauge? It would be best to put a t in your fuel line past the pump so you can view it. Run the engine at high RPM, and see what happens to the fuel pressure.

Your main coil I think is getting hot after a few hours and stopping you.Follow your spark plug wires back away from the engine,one in the middle of your distributor will lead to the coil which is about 3inches wide and 8 long cylinder tube. Mike
Take coil to auto zone for free test,you can pull and replace easily yourself in less than 45 min. Mike
b smith, i guess it does?

i have had someone tell me to take it off and put it back on, i tried that last breakdown and it didnt work.

does just taking the cap off fix a vapor lock (the same someone told me that), or do you have to disconnect fuel lines?

thanks again
i say fuel also.

sounds like the tank might be building up vacuum or the filter is plugging up.

easy to check:

when it dies, remove the filler cap right away. if it makes a loud sucking noise from air rushing in, the you need a vented cap or the lines for the vent are plugged.

if that's not it, then remove the fuel filter and empty it onto a clean sheet of paper ( inlet side down ). once the fuel evaporates, only contaminants should be left on the paper. that'll tell the story.......
If it stops again go immediatly to the carb. if there is no gas in the site glass you know the problem is between there and the tank. Mike
I had this problem with my 1980. It was fine at slower speeds, but on the highway it would act like it was out of fuel. I installed an electric pump to check it and it would run, but it never seemed right. A few years ago I had the carb rebuilt and have not had any problems since. It will run down the highway all day long. Just made a 260 mi. round trip over the Grapevine to Bakersfield on Sat. for the Cruiser get together.
Something to check anyway.

One way to try and decide if it is vapor lock is a cool can make a coil of line to run the fuel through and stick it inside a can of ice and make a run or two. Its an old drag racing trick but of course they dont have to drive for 2 hours!

seems like you got plenty of advice on vapor lock so I am looking at other possibilities--not to say it is one or the other though

As soon as it happens pop the hood and check the float position and amount of fuel in the window

I had a problem with small rust bits jamming my fuel inlet---the float was down and the bowl was empty--I had fuel pressure on the line but it wasnt getting in the bowl---I tried sucking on the fuel inlet and it freed up the seat and a couple little rust bits came out

I changed everything from the tank forward cept the pump and engine line and have been okay since

I know people do it but I dont really like the idea of 2 fuel pumps, one or the other should do the job

let us know how you get on:cheers:
Another vote for lack of fuel. How many fuel filters are you running and what are they catching? One time leaving TN after a week of wheeling and the truck ran great until I tried to get up to highway speed on the drive home. It would buck and run like crap until I backed off the speed and it would run fine. Yep, clogged fuel filters.
I have two thoughts on your problem.

#1 Are your fuel lines connected to the carburetor correctly? The line with the Banjo Bolt is the return line. Double check the lines are not crossed at the pump.

If they are connected wrong, the return line will allow fuel but not enough to run at speed down he highway. It will allow enough fuel to putter around town. In order for this to happen, someone would have had to remove the check valve and spring from the banjo bolt. The hole in the banjo bolt is small.

You also have a screen inside the carburetor where the two fuel lines connect to the top half of the carburetor. You can remove the fuel feed line and look in there an see the strainer screen. It is about the size of the eraser on a #2 pencil and about 2 or 3 time as long. Make sure it is clean. You will have to remove the top of the carb and the float and inlet needle and then unscrew the inlet needle seat to properly access the screen. Don't reach in there with a pair of needle nose pliers and pull it out from the top. If it is plugged or plugging, it is doing it's job.

# 2 You did not mention if this rig is desmogged or not. Make sure your fuel lines are not too close the the air rail. The air rail will get hot and it is one of the leading causes of vapor locking in the metal fuel lines.
I vote fuel as well. Clogged filter or a fuel pump going south. Keep in mind that you might be running lean if that's the case. Could be real hard on your engine.

Vapor lock would hit you in the summer. You can try it at night and I'll bet the same thing will happen.

Heat saturation at the coil would hit you when you stopped for 5 minutes and got back in. Just guessing.

My filter clogs like a mofo. I can go around town all day no problem but when I put the spurs to her she'll fall flat on her face. I've changed filters plenty of times so my problem is in the tank pick-up. I can back blow the line and the problem goes away for awhile. I'll need to drop and clean/replace mine to solve the problem.

Best of luck finding yours.
ok, thanks all....

don't know where i'd be without yall.

inbetween studying for exams, research on sea turtles, and getting letters of recomendation, i have been working on the rig.

so far i have :
checked all lines for wear/tear/damage and found all were in good shape
looked inside lines and all seemed fine
rebuilt the carb - (i think this is going to help the most)
took coil to autozone for free check ( said it was fine, no need to replace)
two filters checked, both sparkling clean
gas tank - spotless
no rust, flakes, or chips in any filter, screen, or the like
the gas cap ??? (it does make a sucking sound, but then again so does the one on the family german sportscar, american sedan, and american truck) i mean, a little noise.
i am still smog control

after rebuilding the carb, no longer do i have to say "dont worry she is just really cold natured". she is now starting right up !!!

interstate travel speeds are good and i have not broke down, i have done a couple runs to and from birmingham-gadsden (90m or so)

on the list to check in the future:
check pump (seems to be working fine but i am no mechanic) does auto zone check these free?
wrap lines with heat insulation

i think the rebuild was it. she starts right up now anyways.

one thing i forgot to mention was that after having high rpm, push clutch in to prepare to stop at red light, sometimes it would die... (could this be related, or is this another type of problem) i think it may have something to do with it since it has not done it since the carb rebuild. and it would only do it once in a while, not every drive.

found this on the autozone website - it may help with future questions

thanks and sorry for the late post....

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