QuestionQUESTION: Howard,
I picked up my cleaned, repaired, and re-lined fuel tanks today only to notice by flashlight inspection that the return pipe in the right tank was swinging freely, and not fastened to the fitting at the bottom of the tank. Of course, I did not notice this before dropping off the tanks, and when I showed this to the guy who did the work, he denied anything in their process would have caused this. I have managed this evening, through creative use of coat hanger wire and a screwdriver, to line the pipe with the fitting, then tap it with a long rod inserted through the level sender hole, to re-seat the pipe in the fitting, up to the stop. So, I have to ask what the return pressure is, and if the pipe may be expected to hold up to this pressure as fitted, or if I would be well advised (or ill-advised) to maybe solder the joint such as one does with copper water pipes. It is a tight fit at this point, and I was not able to knock it back loose with a screwdriver, but I am probably being purposefully gentle. Any thoughts you have would be great. In the extreme hypothetical, if there was no pipe there, and fuel fed back directly to the bottom of a full tank, will that cause other problems?
Thanks!
ANSWER: Sorry Michael, I am not any help an that one because I never had that pipe out.
Fuel does return out of that pipe with some speed but I have no clue how much back pressure is on that pipe while fuel is returned to the tank. I don't think the end of the pipe is closed up any so as to apply pressure on the pipe but there is a little pressure applied to the pipe as the fuel has to make a turn to go upward but then we don't have enough info on how tight you were able to get it by knocking it back in.
Your guess is as good as mine on this.
Howard
---------- FOLLOW-UP ----------
QUESTION: Howard,
Ok, to the extreme hypothetical that I posed, if the pipe were to blow out under this pressure, for some reason, would the fuel returning to the bottom of a nearly full tank present further problems to the system, in your opinion? Since I last wrote, I have considered that it would be prudent to blast some air through all the lines to make sure they are clear, and I imagine if the fitting holds up to the 100 or so PSI of air from my compressor, it should be ok.
Thanks again,
Michael
AnswerI do know that if the return fuel were to enter the bottom of a full tank it would raise system pressure at the fuel rail making the engine run rich. The regulator must exhaust pressure to control rail pressure.
The trouble with the air test is that resistance to flow in the return line with air would not be a good representation of the resistance to hydraulics trying to go through the same pipe.
Your decision should be based on Do you want to gamble on the pipe staying in and what would be the down side if it comes loose? You would need to empty the tank and Make a repair that you are faced with now or make a repair now.
Does the fitting that the pipe fits into come out of the tank? and can you remove the pipe with the fitting removed and if so, you could then check how tight the pipe actually fits into the fitting and if it does not fit too tight, it may be then possible to rough up the end of the pipe so when you force it into the fitting, it would have a good chance of staying. I have never had that fitting out so I don't know what it looks like.
If you could make a sketch of what it looks like and sent it to me as you can send attachments to this program.
Howard
