Isuzu 4BD1 fuel issue

**Bearman** · 22nd July 2017, 12:38 PM

A friend of mine has been in contact with me regarding a strange fuel problem he is having with his Isuzu at Kununurra. Basically what is happening is that it is hard to start in the mornings like it is doesn't have fuel at the injectors. Takes a bit of cranking to get it going and then it's fine for the rest of the day. He's had the injectors done and new nozzles put in, the lift pump recoed and new primer but it is still the same in the morning. He has also checked the non return valve on the top of the pump and reckons it is all right. I suggested to him to crimp the fuel inlet pipe with a set of brake line pliers we he stops it this arvo and see what happens in the morning. It's unlikely to be the IP in my opinion as the motor has done less that 100K and I have never heard of problems with them. Anyone got any ideas?

**Phil B** · 22nd July 2017, 12:42 PM

Has he cleaned the little "bastard" screen on the inlet to the lift pump?
Could also be an air leak on the fuel lines from the tank
Has he checked his glow plugs? Normally don't do much but it is winter. Not cold in WA though so probably not them.

**workingonit** · 22nd July 2017, 03:22 PM

Before starting it the next morning (precluding attempts to crimp lines the night before) unscrew the fuel filter and check level inside - if just below inlet/outlet points of fuel filter manifold then maybe a drain back issue, somewhere.

**Ancient Mariner** · 22nd July 2017, 03:31 PM

Brian some Fiat tractors have a button on the side of the injector pump where you lock it in, in the full fuel position .I think the 4bd1 achieves the same result by depressing the pedal to the floor and release then crank but could be wrong

Noel

**JDNSW** · 22nd July 2017, 03:53 PM

I would suspect an air leak, possibly a very small one somewhere in the fuel system, including downstream of the pump. There may or may not be a slight fuel leak at the same place.

As someone suggested - has the hidden gauze filter under the injection pump been checked?

**123rover50** · 22nd July 2017, 04:16 PM

I dont have the glow plugs hooked up on mine and its been a bit slow to start these mornings.

**Bearman** · 22nd July 2017, 05:35 PM

Originally Posted by Phil B

Has he cleaned the little "bastard" screen on the inlet to the lift pump?
Could also be an air leak on the fuel lines from the tank
Has he checked his glow plugs? Normally don't do much but it is winter. Not cold in WA though so probably not them.

Yes, done that one Phil. Winter in the north is not cold so need for glow plugs.

**Bearman** · 22nd July 2017, 05:38 PM

Originally Posted by workingonit

Before starting it the next morning (precluding attempts to crimp lines the night before) unscrew the fuel filter and check level inside - if just below inlet/outlet points of fuel filter manifold then maybe a drain back issue, somewhere.

I reckon that's what it is as well. For some reason the fuel is draining back from the injectors overnight. Hopefully it will start easy in the morning and prove me right

**Bearman** · 22nd July 2017, 05:40 PM

Originally Posted by Ancient Mariner

Brian some Fiat tractors have a button on the side of the injector pump where you lock it in, in the full fuel position .I think the 4bd1 achieves the same result by depressing the pedal to the floor and release then crank but could be wrong

Noel

It has only just started doing this Noel so something has changed. Normally fires straight up.

**Bearman** · 22nd July 2017, 05:42 PM

Originally Posted by JDNSW

I would suspect an air leak, possibly a very small one somewhere in the fuel system, including downstream of the pump. There may or may not be a slight fuel leak at the same place.

As someone suggested - has the hidden gauze filter under the injection pump been checked?

No apparent leaks John, the gauze filter has been checked.

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