![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Stumbling after 20 miles of driving
So I've got a problem with my truck that takes about 20 miles of highway driving to appear, once it's happens it will re-occur about every 10 miles or more frequent. It stumbles and won't pull, it rarely ever dies, but I have to pull over, if I shut it off and sit for 2-3 mins I can start it up and keep going.
Also when it does this the fuel filter is empty or near empty and no visible sign of fuel is flowing into the filter unless I shut it off as I mentioned. Things I've done so far are; 1. Disassembled and cleaned inside of carburetor. 2. Replaced fuel filter 2-3 times just to be sure. The most recent one is a clear plastic one so I can watch for fuel flow or debris. No debris at this point 3. Pulled fuel line away from all heat sources to eliminate chances of vapor lock 4. Replaced fuel cap with new cap that is vented, or at least thats what they told me at the part store. It does have the vent valve and it does "rattle" 5. Replaced fuel pump, and all rubber line from the pump to the carb. I didn't replace the line betwee the hard line and the pump, but it's not that old and is fuel injection rated line. I think the issue is the rubber line between the hard line coming from the cab and the steel line that runs along the frame. This look as though it could be the original line, it does have spring clamps on it that are not holding very tight as I can twist the rubber line without removing the clamps. The line feels flimbsy. My question is what else might I be missing? I'm going to get some fuel line tomorrow and replace it just because it's questionable. Any ideas? Thanks Last edited by Test Pilot; 02-17-2010 at 11:03 PM. |
![]() |
![]() |
![]() |
#2 |
Registered User
Join Date: Dec 2009
Location: Fort Walton Beach, Fl
Posts: 357
|
Re: Stumbling after 20 miles of driving
when it acts up again pull your cap off the tank and listen for a vacuum. sounds like a venting problem. i had a similar problem on mine till i moved the tank.
|
![]() |
![]() |
![]() |
#3 |
BlahBlahBlah
Join Date: Feb 2002
Location: Wa.
Posts: 19,866
|
Re: Stumbling after 20 miles of driving
Mine does the same thing, but wont go as far as 20 miles before it stumbles. If I let off for a few seconds it "fixes itself" for a little bit, but stumbles again. Never does this just driving around at 50 or less.
Ill be watching this thread...Ive checked all the stuff you have.
__________________
… … … … … … … … ... … … … … … … … … … … … |
![]() |
![]() |
![]() |
#4 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
And while I'm remembering things I forgot to put in my original post, I've pulled the cap while driving and it didn't get better. So I did the whole stop and wait for 2 mins routine. Left the cap off and took off again with the same results. |
|
![]() |
![]() |
![]() |
#5 |
User #12137
![]() Join Date: Apr 2004
Location: kingsport,upper east tenn
Posts: 11,598
|
Re: Stumbling after 20 miles of driving
have you pulled the sending unit in the tank and looked at the fuel pickup sock ?
|
![]() |
![]() |
![]() |
#6 |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
|
![]() |
![]() |
![]() |
#7 |
Senior Member
Join Date: Nov 2003
Location: Brookings, SD
Posts: 10,497
|
Re: Stumbling after 20 miles of driving
What year is your truck? Are you saying your tank is pulling a vacuum, or that it is pressurized?
__________________
Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs. |
![]() |
![]() |
![]() |
#8 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
My 71 Bronco is the same way in terms of pressure, but not the stumbling problem even on a 2 hour treck to the off road park. |
|
![]() |
![]() |
![]() |
#9 | |
User #12137
![]() Join Date: Apr 2004
Location: kingsport,upper east tenn
Posts: 11,598
|
Re: Stumbling after 20 miles of driving
Quote:
and yes change out the rubber line from the pickup unit to the frame hard line as you were talking bout , you have changed everything else so it wont hurt to go ahead and change that also |
|
![]() |
![]() |
![]() |
#10 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
|
|
![]() |
![]() |
![]() |
#11 |
User #12137
![]() Join Date: Apr 2004
Location: kingsport,upper east tenn
Posts: 11,598
|
Re: Stumbling after 20 miles of driving
yup air getting in the line and no gas leakin out sounds weird but
![]() i chased that for over a year on a olds i had and now josh and liz owns it ![]() my uncle told me to double check each clamp and i found 1 that was just loose enough to let air in and not leak gas out |
![]() |
![]() |
![]() |
#12 |
I really hate wet sanding!
![]() Join Date: Dec 2008
Location: Brookfield, MO
Posts: 601
|
Re: Stumbling after 20 miles of driving
What is the longest length of rubber line you have in the fuel lines? Long runs of rubber lines have been known to collapse from the suction of the fuel pump, use hard lines and small prices of hose to connect them together.
__________________
Jeff, 68 C-10 75 C-20, now a C-10! 10 F-150 |
![]() |
![]() |
![]() |
#13 |
Senior Member
![]() Join Date: Feb 2001
Location: New Madison, Ohio
Posts: 21,365
|
Re: Stumbling after 20 miles of driving
This is what's great about this site....one can be Sitting here alone, climbing up the walls trying to solve a problem....then you come to this sight and get help from those who have had similiar experiences. And bingo problen is solved!!!
![]()
__________________
A husband can be right...or...A husband can be happy. ![]() 67-72 Chevy and GMC Trucks...The Classic Truck for the Classic Folk. ![]() 1970 CST Two tone green, 402BB, 400 Automatic, Tach, Buckets, AC, AM-FM, Tilt, GM CB, GM 8 Tract, LWB, etc ![]() ![]() JOHN 17:3...The better side of "LIFE" Remember: Everyday is a good day...Some are just gooder! |
![]() |
![]() |
![]() |
#14 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
|
Re: Stumbling after 20 miles of driving
Does it have HEI?Sounds like the module is giving up the ghost.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
![]() |
![]() |
![]() |
#15 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
|
Re: Stumbling after 20 miles of driving
and the long lengths of rubber lines are great fire starters too,have seen many vehicles burn to the ground due to the lazymans fix for running gas lines
__________________
71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
![]() |
![]() |
![]() |
#16 | ||
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
Quote:
|
||
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Oct 2009
Location: Gardnerville Nv No Mo Cali!!
Posts: 869
|
Re: Stumbling after 20 miles of driving
Mine did the same thing a while back and I traced it to my new Pertronix II module. I changed back to points and the problem was solved. Later I replaced the Distributor with a Delco HEI. I like the HEI but I've had to replace the module twice in two years. Pretty sure it has something to do with shutting the engine down with the air conditioning still on.
|
![]() |
![]() |
![]() |
#18 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
|
|
![]() |
![]() |
![]() |
#19 |
Registered User
Join Date: Feb 2006
Location: Smyrna, Ga
Posts: 1,647
|
Re: Stumbling after 20 miles of driving
the old original line that you didnt replace yet may be collapsing on itself. It will shut off fuel flow at higher rpms, ie. higher fuel pump vacuum.
That loose line is esentially a vacuum leak in your fuel system. it will aerate your incoming fuel and drop the pumps vacuum, thus not pulling fuel. i imagine that your fuel is flowing fine at low rpms and idle, but its having a hard time keeping up at higher speeds. When you switched to HEI did you remove the entire resistor wire going to your dizzy? |
![]() |
![]() |
![]() |
#20 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
There are situations where fuel won't flow at low rpms, indicating to me once it's collapsed, it doen't take much of a vacuum to keep it that way. The truck had HEI before I bought it, so I can't answer that question, but again, without fuel it doesn't matter if I'm getting spark. |
|
![]() |
![]() |
![]() |
#21 |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Success!!!! well sorta.
So far my test drive route is to and from work. I've never made it all of the way to work without the issue. Work is 25 miles one way. So after replacing the line between the tank hard line and the chassis hard line I went for a drive and made it all of the way to where I work and about half way home before the issue reoccured. This time it recovered so quickly that the filter was full when I was able to get out and look at it. What I've done since then. I decided to go ahead and replace the line between the chassis hard line and the fuel pump. I had enough of the line left over from what I bought to do the part between the tank line and chassis line to do this. I haven't driven it yet but I'll have somewhat of an update in the morning. I'm confident enough in it to drive it to work tomorrow. I'll log in from there and give a report. I'll note that I used EFI rated line simply due to the heavier wall thickness and tighter nylon braid embedded into the hose. I also took the opportunity of having the fuel line off to to blow out the chassis hard line, however no debris came out of the line. |
![]() |
![]() |
![]() |
#22 |
Registered User
Join Date: Jul 2007
Location: Toppenish, WA
Posts: 15,507
|
Re: Stumbling after 20 miles of driving
What is happening is that you are pulling a vacuum on the tank with the fuel pump.
think about it for a minute. You only have one line going to the tank and that is to the fuel pump which acts as a vacuum pump to pull fuel from the tank. The cap isn't venting correctly and is allowing a vacuum to build up in the tank. When you open the cap, especially when the tank is below a quarter you can hear the sides of the tank pop back out when the air goes in. I went through three new out of the box caps that were supposed to be vented before I got one that actually was. I even walked to town once to get gas as I thought I was out of gas and then started carrying gas with me and that's when I figured it out. |
![]() |
![]() |
![]() |
#23 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
Also if you read above, I can drive with the cap off. No cap on at all meaning I have a 1.5" hole to balance out with the atmosphere |
|
![]() |
![]() |
![]() |
#24 |
Registered User
Join Date: Jul 2007
Location: Toppenish, WA
Posts: 15,507
|
Re: Stumbling after 20 miles of driving
You are wrong in this case, if you had pressure in the tank it would push the fuel to the pump. As I said before, think about it. The pump pulls the fuel out of the tank and it takes air going into the tank to take up the space. When no air goes into the tank it creates a vacuum which eventually stalls the engine. When you open the cap it is the air rushing in pushing some of the fuel vapors out that you see as pressure escaping
And yes I full and well know that a gas can bouncing around in the back of the truck will have pressure in it just as one sitting out in the sun will but that can does not have a fuel pump pulling against the sealed can. If it did, it would collapse the can.. |
![]() |
![]() |
![]() |
#25 | |
Registered User
Join Date: Nov 2009
Location: Triangle area of NC
Posts: 67
|
Re: Stumbling after 20 miles of driving
Quote:
AGAIN the same problem happens when the cap is on or off the truck!!!! When there is a 1.5" hole in the top of the gas tank, how can it be pulling a vacuum?!?!?!?!?! Last edited by Test Pilot; 02-19-2010 at 12:04 AM. |
|
![]() |
![]() |
![]() |
Bookmarks |
|
|