VWDiesel.net The IDI, TDI, and mTDI source.

General Information => General => Topic started by: mtrans on April 20, 2011, 03:42:30 pm

Title: Puzzle on return line
Post by: mtrans on April 20, 2011, 03:42:30 pm
It`s NA and I suspect of small air leak on return line,so I put clear line on both.Line to tank is full of fuel(and for now it`s all about line from IP to Injector),but to injector NON of fuel, if i put same by hand pump it go to half and stop.Than I close line from IP, and put another line from injector to bottle to see only just drops aftar 30 min,even on high rpm,by the way motor ran OK.
I have little banjo on return from injectors so I lose one and than I blow it has flow so not blocked.Is it possible that there is no flow from injector to IP,and why they put on it anyway(I suspect about it)

ps. I see no presure on aditional line from injectors to bottle,puzzle man aka Quantum-man man as I remmember said that there is no return flow from 193,293 etc.nozzles-injector, and that is because construction of injectors themselvs.Puting 3 bar on every line and it hold.I change fuel filter because I think it created same vacum and air in return line,so I have more cranking,but what about flow you think?
pss.I thinking about blocking that line forever.
Title: Re: Puzzle on return line
Post by: R.O.R-2.0 on April 20, 2011, 04:20:35 pm
the over flow from the injectors doesnt even flow fuel unless your right around wide open throttle, if i understand things correctly..
Title: Re: Puzzle on return line
Post by: 745 turbogreasel on April 20, 2011, 04:20:53 pm
Worn injectors have more leakby.

Blocking the return will stall the engine or blow off a line.

Air in the return- so what? You are done with that fuel anyway.
sucking air at pump input shaft- that might give the impression of air entering at the return, but be a problem.

I may not have read your question correctly, hope this helps.
Title: Re: Puzzle on return line
Post by: 745 turbogreasel on April 20, 2011, 04:22:53 pm
Worn injectors have more leakby.  Flow from the injectors is just a trickle when all is well.

Blocking the return will stall the engine or blow off a line.

Air in the return- so what? You are done with that fuel anyway.
sucking air at pump input shaft- that might give the impression of air entering at the return, but be a problem.

I may not have read your question correctly, hope this helps.
Title: Re: Puzzle on return line
Post by: mtrans on April 20, 2011, 05:20:42 pm
Thanks for responding

R.O.R-2.0
Man I try couple times wide open throttle in my 30 min test and noting

745 turbogreasel
So if i don`t have injectors leakby - than no flow to ip - than I am OK,but samehow not like to be normal for me(no fuel in that line).
 I Block the return FROM INJECTORS TO IP ONLY and what not stall the engine or blow off a line,by the time I try for shure.I didn`t block return to tank of corse.
I got air on seating same how,in a drive it`s OK.
Best
Title: Re: Puzzle on return line
Post by: theman53 on April 20, 2011, 05:37:10 pm
I would think at idle would be when you would have the most fuel unused and returning to the tank.

Hook the lines up just as they were and you won't have any problems with that side. If you are getting air then you probably have something before that giving you trouble...from the filter to the IP most likely.
Title: Re: Puzzle on return line
Post by: rabbitman on April 20, 2011, 10:34:57 pm
the over flow from the injectors doesnt even flow fuel unless your right around wide open throttle, if i understand things correctly..

I have clear lines on the injector barbs and I can see them flowing at idle. I haven't revved it to compare though.
Title: Re: Puzzle on return line
Post by: mtrans on April 21, 2011, 03:55:16 am
Air and return to tank isn`t problem.
Problem is RETURN TO IP from injectors,as I see this pump can (and must) deliver up to 3 times more fuel than one need,so look like I have same magic there,and I

drive it w/o problem on high rpm so I have enough fuel.

I think long time ago,when I put clear lines I have fuel in both return lines or not ?
In a few years on forum I never heard anything like this,so help me to have fuel instend of air in that line.
ps.injectors are tested 2k before.
Title: Re: Puzzle on return line
Post by: theman53 on April 21, 2011, 07:27:55 am
I don't see any problem. I would think this to be normal. I must not understand, what is the problem with little to no fuel going back to the pump from the injectors?
Title: Re: Puzzle on return line
Post by: mtrans on April 21, 2011, 12:32:20 pm
Problem is because line is not only empty there is air,that air is sucked by seating overnight.So that I was pump before up to 1/2 line is gone.
Yea,I know you will say chek air leak,but puting 3 bar on every line and it hold,and no flow at all,before clear line I`ll bet that`s full. t
Does anybody have empty line from injectors to IP like me?Best
Title: Re: Puzzle on return line
Post by: R.O.R-2.0 on April 21, 2011, 12:39:28 pm
Problem is because line is not only empty there is air,that air is sucked by seating overnight.So that I was pump before up to 1/2 line is gone.
Yea,I know you will say chek air leak,but puting 3 bar on every line and it hold,and no flow at all,before clear line I`ll bet that`s full. t
Does anybody have empty line from injectors to IP like me?Best

pressure may not make the line leak. may need to apply suction to find a leak..
Title: Re: Puzzle on return line
Post by: mtrans on April 21, 2011, 04:27:58 pm
pressure may not make the line leak. may need to apply suction to find a leak..

Thx,but I have only compressor.
Q is for this pazzle:Does anybody have empty line from injectors to IP like me?Best
Title: Re: Puzzle on return line
Post by: 745 turbogreasel on April 21, 2011, 05:38:23 pm
It's a return line, and can't interfere with engine operation(unless plugged) why do you care?
Title: Re: Puzzle on return line
Post by: rabbitman on April 21, 2011, 10:06:59 pm
Mine have a little air in them, it stays because there isn't enough flow to push the air down from one injector to the next.
Title: Re: Puzzle on return line
Post by: mtrans on April 22, 2011, 10:15:51 am
Thanks on replys,
I`ll put same fuel and see,after holiday.