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Help with diagnosis?

JJRJR

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Hey guys, most of you have been following the saga of my 69 RR. Runs for a day, then back on the tow truck. OK, so I wanted to throw out there what exactly is happening and a short timeline of what has been done to the engine, etc. so maybe it will ring a few bells.

Dropped her off to a "mopar guy" for carb tune, 1" carb spacer, fuel leak fix, kill switch installed. Once he got the carb adjusted and the spacer installed, she ran the best she ever has. I drove her home over 40 miles without incident. Parked car in my garage for a week; started up on a Sunday morning perfectly and drove about 5 miles or so, then she bogged down and gave out. This is when the problem started, out of nowhere. Towed back to the shop. He found debris in the carb that was jamming up the fuel, ran great. Apparently he took only for a short test drive because my buddy Jim ran up there to pick it up last week and he got about 5 miles and same thing happened to him, just gave out.

When it cools down, she runs fine, then once she's up to temp, she dies.

As I am typing this, the guy at the shop just called me and told me what he found, but he isn't sure WHY it's happening. Here goes. . .

He starts her and it runs perfectly. Let her get up to 200 degrees, took off air cleaner to see carb, get engine up to 2 to 3,000 RPM, and he's telling me that he can see bubbles in the front sight glass on the Pro Systems carb. Carb is not hot, but he says the fuel line from the block to the carb is hot. Says this is where those lines run out of the factory so he doesn't understand why the gas has bubbles in it.

Once she cools down, fine again, then same drill.

Anybody have any clue as to what the bubbles in the front signt could be? Why would the gas be getting that hot? Maybe it's not boiling, but air in the gas? I don't know. He said he'll look further into it this week, but wanted to throw it out to you guys.

The strangest thing is that it ran 40 miles at 3500 RPM perfectly just before this started happening.

Any thoughts guys?

Thanks, John.
 

JJRJR

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A couple thoughts. Is it possible that the gas tank isn't venting properly and when the vacuum builds up it is starving for fuel? I guess to check that we could loosen the gas cap and run it again. I'm baffled by this and it sounds like the mechanic is as well. Any help appreciated.
 

69hemibeep

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Might be a venting problem, if I remember you had the gas tank vent plugged that was leaking? if so open it up and see if it dies. Also the fuel line on the engine was ok with the good old gas but now you have 10-15% ethanol, do you have a vapor return to the tank? I have cured all 3 of my old car fuel issues by adding the return!
 

JJRJR

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69hemibeep said:
Might be a venting problem, if I remember you had the gas tank vent plugged that was leaking? if so open it up and see if it dies. Also the fuel line on the engine was ok with the good old gas but now you have 10-15% ethanol, do you have a vapor return to the tank? I have cured all 3 of my old car fuel issues by adding the return!


We ended up fixing the vent tube leak by just adding more rubber fuel line between the metal vent tube and the gas tank, so they are not plugged. What does a vapor return do? I am 99% sure I do not have one, but wondering what it does and how it could effect fuel in the carb from boiling/bubbling?

Thanks,

John
 

JJRJR

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69hemibeep said:
http://69roadrunner.net/phpBB3/viewtopic.php?f=6&t=5933&hilit=vapor+return


WOW, thanks. Sounds like exactly what is happening. Going to have him install a fuel pressure gauge as well. I forwarded the info to the guy, so I'll keep you posted. Thanks so much.

John
 

JJRJR

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69hemibeep said:
Might be a venting problem, if I remember you had the gas tank vent plugged that was leaking? if so open it up and see if it dies. Also the fuel line on the engine was ok with the good old gas but now you have 10-15% ethanol, do you have a vapor return to the tank? I have cured all 3 of my old car fuel issues by adding the return!

My tech is concerned with where to install the vapor return line at the tank? His concern is that if we cut into the vent tubes, he's saying that it will be liquid fuel traveling back to the tank, not vapor and may leak from the existing vent tubes? Thoughts on how to install the return line?

Thanks,

John
 

69hemibeep

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JJRJR said:
69hemibeep said:
Might be a venting problem, if I remember you had the gas tank vent plugged that was leaking? if so open it up and see if it dies. Also the fuel line on the engine was ok with the good old gas but now you have 10-15% ethanol, do you have a vapor return to the tank? I have cured all 3 of my old car fuel issues by adding the return!

My tech is concerned with where to install the vapor return line at the tank? His concern is that if we cut into the vent tubes, he's saying that it will be liquid fuel traveling back to the tank, not vapor and may leak from the existing vent tubes? Thoughts on how to install the return line?

Thanks,

John
You should have 2 vents at the tank, I would use the short one that was leaking but just use it don't T into it. Unless you have a 3/8" pick up, it would have the return on it like the one below.

roadrunner restoration 916 (640x480).jpg
 

Basketcase

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try a shadetree solution...secure a gas can under the hood, and go for a ride. might even try a 5 gallon can and run some fuel hose so you can secure the can in the trunk. see how the car runs. If it's OK, this would let you know if the tank or the hard line is the problem. I had my first '69 die like yours. It had been sitting at least 10 years when I got it. Got it running pretty quick. It would haul ass until I went up a hill then it would die. coast back on the level, and it fired right up. changed carbs, pumps, filters, same thing. dropped the tank and the inside looked like the Titanic. the sock filter in the tank was plugged. changed tanks and problem solved.
 

JJRJR

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69hemibeep said:
Might be a venting problem, if I remember you had the gas tank vent plugged that was leaking? if so open it up and see if it dies. Also the fuel line on the engine was ok with the good old gas but now you have 10-15% ethanol, do you have a vapor return to the tank? I have cured all 3 of my old car fuel issues by adding the return!

One more question. I found that my sending unit does have a nipple for a return, my question is do I just use rubber fuel line from filter to tank as my return or is there a metal line I need to order??

Thanks

John.
 

george68hemirr

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METAL LINE...THE LESS RUBBER THE BETTER.....ID LIKE TO KNOW WHERE ALL THAT BLACK CRAP IS COMING FROM THATS GETTING IN YOUR CARB.....SOMETHING IS BREAKING DOWN
 

JJRJR

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george68hemirr said:
METAL LINE...THE LESS RUBBER THE BETTER.....ID LIKE TO KNOW WHERE ALL THAT BLACK CRAP IS COMING FROM THATS GETTING IN YOUR CARB.....SOMETHING IS BREAKING DOWN

Thanks. I'll see it inline tube has something. He found that one piece of what he thought was rubber hose, but nothing since then.
 

69hemibeep

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JJRJR said:
george68hemirr said:
METAL LINE...THE LESS RUBBER THE BETTER.....ID LIKE TO KNOW WHERE ALL THAT BLACK CRAP IS COMING FROM THATS GETTING IN YOUR CARB.....SOMETHING IS BREAKING DOWN

Thanks. I'll see it inline tube has something. He found that one piece of what he thought was rubber hose, but nothing since then.
I was going to say I got my lines from inline tube. Tell them you need the return or small tube for a Hemi car. and the clips to attach to the fuel line.
 

JJRJR

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69hemibeep said:
JJRJR said:
george68hemirr said:
METAL LINE...THE LESS RUBBER THE BETTER.....ID LIKE TO KNOW WHERE ALL THAT BLACK CRAP IS COMING FROM THATS GETTING IN YOUR CARB.....SOMETHING IS BREAKING DOWN

Thanks. I'll see it inline tube has something. He found that one piece of what he thought was rubber hose, but nothing since then.
I was going to say I got my lines from inline tube. Tell them you need the return or small tube for a Hemi car. and the clips to attach to the fuel line.


Thanks so much for your help. Spoke to my wrench guy today and I'm going to order the parts and he'll install the return line and vapor return fuel filter for me. Just to be sure, are the fuel pumps for the 440 and Hemi cars in the same spot as the 383's? Also, someone else on this site used Purolator filter PN F20030, so I assume this is all I need?

Thanks again,

John
 

69hemibeep

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JJRJR said:
Thanks so much for your help. Spoke to my wrench guy today and I'm going to order the parts and he'll install the return line and vapor return fuel filter for me. Just to be sure, are the fuel pumps for the 440 and Hemi cars in the same spot as the 383's? Also, someone else on this site used Purolator filter PN F20030, so I assume this is all I need?

Thanks again,

John
You got it :thumbsup:
 
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