Fuel flow from injectors back to the tank

aldo · Post by **aldo** » Thu Sep 04, 2008 12:53 pm

Hi everybody. I disconnected the fuel return line that runs from the injectors back to the tank, to check to see how much fuel was in there. It was empty. So I started her up with the return line disconnected, and run it for about 10 minutes, at fast idle, and sometimes revving high for 30 seconds or so. Not a drop came out. Is this normal for a Dexta? How much fuel should be flowing back to the tank?
I unbolted the return line from the tops of the injectors, and the injectors were all full of fuel, so it appears that there is very little if any excess fuel that need to flow back. She runs beautifully by the way, no problems at all.

Thanks for any help.

terry274 · Post by **terry274** » Thu Sep 04, 2008 1:50 pm

Aldo, here is what the repair manual has to say:
"Fuel, which leaks past the injector nozzle valve, lubricates the valve stem before returning to the fuel tank via a common leak-off pipe."
It would seem to me that very little fuel is meant to leak past the injector valve. But I don't really know, this is the first diesel engine I have owned. Sorry to not be of more help.
Terry

Grani · Post by **Grani** » Thu Sep 04, 2008 6:10 pm

If You do heavy work with it then it is comming more but not much. On one of my Trader 590 engines I don´t have it connected at all and nothing is comming out of the hole.

aldo · Post by **aldo** » Fri Sep 05, 2008 11:07 am

Thanks Terry and Grani. So if you have read my other thread, I was looking to use this return line as the fuel supply for the cold start heater plug. Seems like that idea doesn't work in my case.

Post by **Brian** » Fri Sep 05, 2008 11:34 am

If you take that pipe off and lreave it open on a Dexta you will soon loose a lot of diesel. When a Major injector return leaks into the sump they soon fill it up so to say there is nothing in the line is not true.

You are not giving it a fair test by not running for a while. The modification is the way Fords did it on all the later tractors and they just used a straight pipe to the heater. Take it from me it works and we have used it many times when the pump has failed.

aldo · Post by **aldo** » Fri Sep 05, 2008 12:20 pm

You're right Brian, not a fair test, I was just expecting to see some sort of flow.
Actually the very low flow rate is somewhat reassuring , because I was worried that if all those loops were to fill with fuel, much too much fuel would be delivered to the heater plug. The very low flow rate means I'll be lucky to get maybe 1-2 mL, don't know. However I do often use the tractor for short periods of maybe 10 minutes, running at fast idle, moving things around in the bucket. Maybe then there won't be enough in the line for the next start.