7211 fuel problem

[andys]

Hi. I have a 7211 which I've owned since may, it starts on the button every time. Its been fitted with an electric diesel lift pump which I've never had to use. The other day I came to start it and nothing, just turned over on starter and didn't even try to fire. I checked there was diesel in tank there was, put some in as good measure, bled the pump and she started, good thought this was the end of it. However after around 2 mins she spluttered to a halt,so switched lift pump on again bled and off she went, left pump on all ok, soon as pump switched off stops. Leave it for 10 15 mins and it won't start have to switch pump on crack bleed nut on pump and then ok. Can't understand why pump has to be on now when I never needed it before, could fuel be running back from pump? Any help appreciated, cheers Andy.

 

[hala]

Have you checked the mecanical liftpump. To me it sounds like no fuel is pumped by the ordenary liftpump however the electrical keep up the fuel flow when its on. Check if you have a fuel flow from the liftpump when you crank the engine with the elecrical off. The mecanical pump might to be replaced?

Hazze

 

[andys]

Hi. The mechanical pump has been bypassed, there are no pipes to it, it was like that when I got it, looks like its been out of service a while filter bowl very dirty. Thanks for reply.

 

[hala]

Do I understand You right that the tractor in the past has worked with the electrical lift-pump off and the mechanical pump bypassed? If so it is a mystery for me.
One way of solving the problem with fuel flowing back to the tank (a classical problem ) and get a quicker start is to use an electrical pump. One reason why fuel flowing back to the tank might be a minor air-leak in the fuel system including the rubber hoses going back from the injectors to the injector pump. Air leakage could be very difficult to find.

Hazze

 

[sb]

i maybe wrong . But i would think you would have to leave lift pump on when your using tractor.. how else is the injector pump going to get fuel .. thats what the tractors own pump does and your saying that bypassed.. i would think that pump should turn its self of when in gets pressure up. and only run when needed

 

[sb]

forgot to say if you think the diesel is returning from pump .. you can buy a non return valve and stick it on .. your get one on ebay for around a 5stg

 

[hala]

Many electrical pumps allready has a one way valve built in. Most electrical pumps is just working when its needed just as sb just said.
The good with the electrical pump is that it starts pump and filling the system before you crank the engine, the same job as the hand pump will do, if the fuel had flown back to the tank. However try to find out why its flowing back, look for air leakage.
Hazze

 

[andys]

That's right guys the pump has an on off switch on the dashboard and it's independent from the ignition, I have never used it until the problem started last week. The electric pump is piped straight to the primary filter, I'm a bit baffled as well as to why its been working without the pump, gonna follow the wires back and see where they go. Thanks for the help .

 

[hala]

Interesting! Could it be that it is conected throug ignition with an option to switch it on when the ignition is off to simulate the hand pump before starting the engine and now there is no conection via ignition due to i.e. blown fuse? Please let us know the outcome.
Hazze

 

[hve]

Interesting! Could it be that it is conected throug ignition with an option to switch it on when the ignition is off to simulate the hand pump before starting the engine and now there is no conection via ignition due to i.e. blown fuse? Please let us know the outcome.
Hazze

That would be my guess
No way the Zetor Injection pump will suck up from an under cab Tank without any lift pump, let alone having to suck it through the electric lift pump.
Don't spend too much time on the why or how ......... just make sure there is power at the pump when the ignition is on and you will have a permanent solution, better than the factory setup that gives lots of problems with air leaks (judging by the number of similar posts on this site)
Also bleed-back will not be a problem with an electric lift pump, as soon as you switch on the ign you will have fuel circulating through the injector pump and back to the tank, all air expelled

 

[andys]

Thanks for all the replys. I've wired the lift pump so it's on when ign is switched on and had no more problems.

 

[zsolt]

Hello every one!
I have a problem on my 7211 and I'm looking for ansvers to it.
So basicly we did the maintmenc (fuel filter), and took the gas tank down so that we can wash it. Then we asembeled it all back upp again and the engine didnt get enof diesel. In the litle cup where you hand pump the diese, vacume is apearing. We tried to bleed the sistem and it didn't work. So i'l be weary glad if someone can halp mi whit this problem. Thx

 

[zsolt]

Hello every one!
I have a problem on my 7211 and I'm looking for ansvers to it.
So basicly we did the maintmenc (fuel filter), and took the gas tank down so that we can wash it. Then we asembeled it all back upp again and the engine didnt get enof diesel. In the litle cup where you hand pump the diese, vacume is apearing. We tried to bleed the sistem and it didn't work. So i'l be weary glad if someone can halp mi whit this problem. Thx

 

[diyfarmer]

When you bleed up the system, make sure you have tank 3/4 full first, then open the banjo bolt on the second filter and using the hand pump, pump it the well until diesel is flying out then tighten and try starting and if you have a second person to keep pumping the primer while you are turning over the engine. Be sure you have the hand throttle open to the last.