fuel from pump to carb question

[sactoC10]

Have any of you transplanted the line from the fuel pump to the carb with a partial rubber fuel hose or something different than the stock metal line?

I thought I'd resolved my possible "vapor lock" problem, but yesterday the wicked thing returned. I was about 2mi from home after driving around town with the kids (plenty of time for things to get real hot) and old yeller started bucking on me, sort of wanting to stall...but not quite stalling completely.

My wonderful 9 year old daughter said, "Stop doing that daddy!" To which I said, "I'm not doing that." And she replied, "I see your foot dad, stop." I then explained that I was trying to keep the darn thing FROM dying. (part one)

Then, about 3/4 mile from home on a busy 5 lane road, I did not win the battle, truck stalled and we rested in the "suicide lane" for a minute. Then I said, "hold on kids" when it fired back up and I threw it into drive with the RPM's up there. Figured I could coast most of the way from there with a BIG wheel spinnig screech back into traffic if it died again, but fortunately we made it right into the driveway. (part two)

My fuel line is up against the water hose that exits on that same side of the engine. I am thinking (guessing) that this may be the area where the fuel is getting REALLY hot before reaching the carb when the engine and water through that hose are very hot...NO?

Little help...please!

[JIMs70GMC]

That sounds like the fuel filter to me.

[sactoC10]

I checked, cleaned/replaced anything and everything fuel filter (at the carb) related when I thought I'd beat this problem a few months ago. There was also a big FUGLY fuel filter beneath the tank that was in line to filter the gas from all three tanks (when the truck had saddles installed), which I removed and replaced with new hose.

This problem was worse (and felt different) several months ago. My older daughter was driving the truck (practicing in a parking lot) when it would just die after getting hot, which triggered me to try and ifx the problem.

Problem remains, just taking longer to occur.

[1971LT1SWBPOSI373]

If your fuel gets warm or hot in this area it still wouldn't lock up. I've seen folks with braided fuel lines laying on the hot intake manifold and they don't have problems.
I agree with the prior post, first check the easy stuff. What's the condition of your fuel filter? Check all of your lines comming underneath from the tank and make sure they aren't kinked or dented restricting the fuel flow. Be very careful... take a sealed flashlight and shine it into the filler neck looking into the tank, is there a lot of rust or sediment on the bottom of the tank? The last thing I would check is the fuel pump. About 5 years ago I had a fuel pump that had a ruptured diaphram in it. It was still able to pump fuel but not very well. It had me stumped for weeks thinking it was a carburator problem. I took the fuel line off and put a rubber hose on it directing it into a can. I had a friend crank the engine and fuel barely flowed. Fuel should flow with good quantity. I bet you'll find your problem if you check these items. TJ

[kaycee]

What about the sock on the float inside your tank maybe it is full of snit,maybe your fuel pump not delivering enough may need a fuel regulator so it gets a steady psi.What about coil hot wire is it hitting somethig hot manifold,header etc.I did have a coil at 1 time do this it turned out to be the coil itself.Hope this helps GOOD LUCK

[sactoC10]

OK...

I'll re-check the filter and re-inspect everything. Good Thanksgiving Day morning "start-the-hoilday-right" thing to do. No family gathering until late in the day!

I've heard that the rubber portions of line can collapse...

What other things could this be? Could it be that I was simply very low on fuel and related to pressure in the tank or particles floating around in the tank? Wonder if this would happen with a full tank of gas?

Hmmm...

It really seems HEAT related as it never happens cold, have to make some time to check the coil too. Just check the lines and where they are positioned?

[cc_bob]

I had a similar problem with my truck, it had a glass inline filter that you could take out and clean. I cleaned it with carb cleaner and everything, still would not run. I finally looked closer at the screen and it had shallack (sp) on it causing it not to flow. I replaced with a regular paper filter and have not had any trouble.

As for your gas line, if you wanted to re-run it go to the parts store and pick up som steel brake line. Bend it similar to the old one allowing more clearance where it might get hot.

Good luck

[kaycee]

The sock in the tank can cause alot of problems they r pretty easy to get out especially if your seat folds forward.Have you ever taken the fuel line off and seen if it is getting fuel when it quits on you?

[sactoC10]

No, I've not removed the fuel line to check when this has happened. That is something I need to put on the "THINGS TO DO" checklist.

My seat does not fold down, but removing it to get in there and check out what "might" be going on in the tank is no biggie.

I really think that my lines are all intact, no bends or disfiguring anywhere. Seems as though I've looked at them numerous times, but not from the sending unit to the floor/underside of cab.

[kaycee]

You don't have to remove the seat but is easier to get to,I just slid my seat all the way forward and was able to get it out.If you r gonna take your seat out then I would take the tank out and flush it out allso and see what crud was in there.GOOD Luck

[67ChevyRedneck]

I'm not sure if this helps but...on my truck I had a big inline fuel filter, thinking bigger is better, the edelbrock carb has a filter where the line goes in, and the pick-up in the tank has a screen on it. My truck, 67 chevy with a 350, has the stock mechanical fuel pump and my truck would sputter, I recently swapped I-6 for crate engine. Changed filters, cleaned carb twice, and replaced fuel pump, same problem. Turned out that my fuel pump wasn't stong enough to suck the fuel from the tank to the carb with that big filter. Maybe you should consider a smaller fuel filter coming out of each individual tank before the three lines come together, so each tank has it's own filter and the fuel will only be pulled through the filter on the individual tanks. Also, one last trick. Get the truck running. Wait until she starts sputtering. Since you have rubber hose take the fuel line between your fingers and squeeze it. You should feel the fuel "pulse" between your fingers, if you don't you have a problem. Either vapor lock, or plugged fuel filter, bad fuel pump, etc....but if the flow is good, tear your carbeurator down and clean it. If your careful you don't even need to buy new seals. If your carb is dirty the truck is being choked with too much fuel from the floats being stuck open OR not enough fuel because the filter is plugged. Dirt will settle in a carb when the motor is not running. Once the fuel is flowing again the dirt will once again be "sucked" into the tiny jets in the carb and plug it. By the way, even if clean the filter at the fuel inlet on the carb doesn't mean the carb is clean. The dirt is so tiny IT DOES and IT WILL get past the filter. If you shut the truck off and let it sit and settle, it will start and run again for a little bit....maybe its not getting hot...its dirty! Hope I helped!

[67ChevyRedneck]

Forgot something...make sure that you used actual fuel line rubber hose on your engine. Fuel will eat any other type of hose and rot it causing tiny leaks. Be another small thing to check.

[1971LT1SWBPOSI373]

And here's another thought. Make sure your tank is venting properly. Some trucks vent through the fuel cap, others through the vapor canister system.
If you see rust in your tank then go after the sock on the fuel line (sending unit) If your tank is clean then check your fuel flow by taking the line off at the carb and turning the engine over (but remove a coil wire or hot wire to the hei so your engine doesn't start on the fuel remaining in the float bowl of the carburator). Do the easy stuff first.

[chickenwing]

Hey, Jeff! Sorry to hear about your problem. I agree with Redneck that you could have a dirty carb bowl. I hate to take em apart though. I'm allways scared I'm gonna screw something up. I like the check out the fuel delivery idea before tearin into the carb. When I took out the sending unit/pick-up from my old tank....eeeuw! The thing was caked over with all kinds of funk.

I can come over tomarrow for a couple hours tops before I have to go to our festivities. Sides, I wanna show off my truck! Could help ya run through it. Show you the filter I'm using also. Worse comes to worse I have an extra can of U.S. Standard fuel tank sealer you can have.

[sactoC10]

OK...

67ChevyRedneck,
I've already removed the saddle tanks and large filter that used to be there with them. Just have the rubber line there now where it was (under the cab). There is no more rubber line anywhere and it shouldn't pulse between the tank and pump, right?

1971LT1SWBPOSI373
Another possibility...old gas cap was problem, broken rubber and what not. New gas cap is tight and sometimes I get a suck or whoosh when removing it, that a problem?

kaycee
Good heads up re:seat, hadn't thought of that, but probably would have tomorrow!

chickenwing
How's 10:00? Got to take my kids to their mom's at 9:00, should probably be getting ready to join the family sometime after noon. Anytime between 10-12 sounds good to me. I'll get you a PM with directions.

Yeah, it's a drag, but so far so good. Since I can always get it to start back up, not bothering me all that much (yet). When I asked the kids, "Which truck are we taking?" They chose the 71 rocker. They know how it goes, they've been stuck with me before, or close to it, in the old 68 stang and the previous 55 F100... all part of the fun!

[chickenwing]

Jeff you shouldn't get a whoosh. If you only have one tube on your sending unit the cap should be vented. 10:00 sounds good at the moment but must check with Mrs. Smith to make sure it does not interfere with the days festivities.

[1971LT1SWBPOSI373]

If you gut a suck or woosh when removing the fuel cap then you have a problem. Your tank is not venting and that could be all or part of your problem. If your tank is vacuum locking on you your pump might not be able to pull the fuel. I had that same problem on my truck and I determined that the vacuum probably ruined my fuel pump by cracking the diaphram. Sounds like your making progress.... Keep looking!!!!!!!!!!!!

[sactoC10]

Changed the cap about 2-3 months ago. First time I stopped for gas with new cap I was sort of surprised that I got some fuel on my fingers removing the cap. (thought, how the heck did the gas get way up top here?) Did not think any more about it. Second time with same cap, definitely noticed a SUCTION and whoosh when I removed the cap. Really haven't noticed it since, but probably stopped paying attention to it.

So, where do I search for this gremlin?

[chickenwing]

No gremlin. Just got to buy a vented cap. Don't know what year/models had a vented cap to tell the parts guy. Anyone else?

[sactoC10]

Aren't California truck tanks vented themselves, up into the cab and then that line going to the charcoal canister?

[RON WOODGEARD]

The behind seat tank is vented up into between the inner and outer roof, .. As said before, There should NOT be a Swoosh.. This is causing a Vacuum Condition in the tank and not allowing the line to run fuel smoothly and freely into the carb.
I don't have my old tank around to look at it to help give you good description of how it's vented.. But, look the top passenger side of the tank and there is where you should see the vent lines.
As I typed a few months ago, this can be a very irritating condition, I remember....

Do you still have the Charcoal canister in it and hooked up? If so undo the line at the canister and see if you can blow air through it with your mouth.. somewhere at Venting you have a Plugged line.

As far as changing the fuel line to rubber from the Pump to the Carb, That's absolutely not a problem.. Probably not a fix in this case, but not a problem either.. Mine's Steel braided now.

Good luck, before it dies in front of the Ex's house..

[sactoC10]

You remember my previous story! Very good... my checklist is getting long, but that's OK.

Yesterday after I parked it in the drive way with the hood up, my wife came out, saw me standing there looking at my fuel hoses and said, "What are you doing?" and sort of chuckled... I must have looked really befuddled and confused.

AND YOU KNOW WHAT! Now that you mentioned it...(GEEZ), I removed the canister and may have thrown a cap on the line to "keep debris" out of it...can you say OOPS! This is the first thing I'll be checking!!!

[cableguy0]

if you pulled the can just let the line be open and vent to the air. the charcoal canister is actually a useful piece of emissions equipment it sucks up the fuel vapor and doesnt have any adverse affects on performance if that line is plugged i bet your problem lies there

[67ChevyRedneck]

Hmmmm, not from Cali, never would have thought of that, but in answer to the rubber fuel question....I might have miss-spoke. The line shouldn't actually "pulse" like your veins, but you should feel a steady flow of fuel. If that emissions stuff isn't your problem, cleaning the carb is the only think left i can think of...other than some serious...and weird...motor/fuel problem. PS glad your kids love the truck. My grandpa had a 72 1 ton and I rode everywhere in it. When I had a chance to buy an original rust free 67 from another family member when I was 15 I JUMPED at it!!

[Gator70]

Hey sacto, I spliced into my pump to carb line(mostly because I kinked it), I run a 3/8 clear inline filter as well as the carb filter. I like the clear because you can see if there is fuel(takes some of the guesswork out). I have not had a problem with lines collapsing. The only thing is mine tends to shake a little with the motor running. Its a good idea to try and brace it against something. Dont have any advise for the emmission stuff my truck is pre emmission.