question Zetor 5340 starting trouble

[djsumcp20oldleawharfcouk]

Have to press plunger many times before starting, replaced hose from tank to engine fuel pump, but still the same. Decided to install a electric pump, installed it by tank and connected hose to engine fuel pump. Started ok first time but after 4 days same problem had to press plunger many times before starting. I can hear pump running when I insert the key, the electric pump does not allow diesel run back to tank,so why is there not diesel at engine fuel pump. Should I by pass the engine fuel pump/glass bottle and filter and connect direct to main filter?

 

[hala]

Not sure it will help your problem but replace the return hose from the ejectors back to the injection pump. Difficult to access behind the injection pump but it is possible. Also replace the hoses between the tops of the injectors that connect all four and then go to the injection pump. Has done the same way on my 4340 and it has worked for probably 5 years. When you turn on the electricity and the electric pump starts, dose it stops after a few seconds when it has built up the pressure? Do you see any airbuble in the glasbowle?
In my country, the model was sold with a small tank at a higher level than the injection pump that was filled with diesel before the diesel overflow back to the main tank. this small tank ensured that the injection pump was constantly filled with diesel. I removed this arrangement when I installed my electric pump.

Hazze

 

[djsumcp20oldleawharfcouk]

Thanks for the reply, the electric pump does not stop, there are no air bubbles in the glass bowl. Why do the return hoses affect it?

 

[hala]

Do not know why the return hose affects the injection pump but was advised by a Finnish specialist on Zetor tractors. Air must not come into the injectionpump the backway espessial if the oneway valve in the pump is not 100%.
My electric pump stops when the pressure has built up and only pumps when the pressure drops, i.e. when the engine is running on fuel . I have read on this forum that if you keep the regular lift pump, the pressure from the electric pump may only be a few psi. What type of pump do you use? I use a HUCO12V 133010 suction pump that gives 2,1 psi overpressure and sucktion hight1,5 m. When the tank was over the engine level you never had this type of problem so I guess the electric pump makes sure to simulate the same condition.

 

[djsumcp20oldleawharfcouk]

Thanks
The pump was off ebay https://www.ebay.co.uk/itm/372866138709 does not give much spec, with pipe disconnected at glass bowl into a bucket pumps quite good.
Think I will bypass mechanical pump.

 

[hala]

the pump you have chosen seems to be a pump to be mounted very close to the tank and is a pressure and not a suction pump. check that it really sucks up enough fuel . I have in mind that the regular lifting pump gives about 16 psi but can remember wrong.

 

[djsumcp20oldleawharfcouk]

Electric pump will suck 1m above tank and pumps ok into a tub.
Hoses from mechanical pump to filters/injector pump looked cracked, no leaks though but air could be getting in. How are they fitted to the banjo joints just pushed on, there are no clips? What is the size of hoses is it 6mm?

 

[hala]

The hose is pressed on the banjo joint. I belive you have to buy a premade hose with the banjos. It might be
https://www.atpmotor.cz/en/e-shop/7563-fuel -supply-pipe-i-4320-7340-l-12-12
Please check it up.
Hazze