Izuzu Engine - Strange running

[Momac]

It would be so easy to check whether removing the fuel filler cap cures the fault when it develops. I agree with others a clogged tank breather may well be the fault. If not a fuel filter may be clogged.

 

The auxiliary battery light appears to refer to the domestic battery bank and indicates whether they are receiving a charge (or no charge if lit) . If you have a separate dedicated starter battery and  a split charge relay the auxiliary batteries may not charge until the starter battery is fully charged . If this take a long while to go out suspect a fault with the starter battery or the split charge relay.

[Canal Cuttings]

MartynG wrote: "It would be so easy to check whether removing the fuel filler cap cures the fault when it develops."

12 hours ago, WJM said:

when the problem first occurred I opened the fuel filler cap in case a partial vacuum was causing fuel starvation. There was no noticeable pressure difference and the engine continued to struggle.

[Neil Smith]

The electric pump is only needed to prime the main diesel pump, once running the main pump does all the pumping.

Neil

[Tony Brooks]

1 hour ago, Neil Smith said:

The electric pump is only needed to prime the main diesel pump, once running the main pump does all the pumping.

Neil

I am very unsure about that, especially as some Isuzus have individual injector pumps. This is probably correct for the rotary pumps that use a transfer pump but I think its pushing it a bit to expect the depression caused by the descending pumping element to pull fuel all the way from the tank and through filters. Even more so as most modern engines have a significant leak back to the tank from the lift pump side of the injector pump(s) and/or filter to make them self bleeding. If the elements were producing significant "suck" I think it would more likely draw air from the leak back system.

 

On most narrowboats the fuel tank position is such that it can feed by gravity so that may give the impression that the lift pump is only for priming.

 

Very hookup to be proven wrong on this.

 

[Flyboy]

5 hours ago, Tony Brooks said:

I am very unsure about that, especially as some Isuzus have individual injector pumps. This is probably correct for the rotary pumps that use a transfer pump but I think its pushing it a bit to expect the depression caused by the descending pumping element to pull fuel all the way from the tank and through filters. Even more so as most modern engines have a significant leak back to the tank from the lift pump side of the injector pump(s) and/or filter to make them self bleeding. If the elements were producing significant "suck" I think it would more likely draw air from the leak back system.

 

On most narrowboats the fuel tank position is such that it can feed by gravity so that may give the impression that the lift pump is only for priming.

 

Very hookup to be proven wrong on this.

 

I fully agree with you on this one. I don't of any narrowboat engine that will suck up fuel without a lift pump. They will run on gravity feed though even if the electric pump is faulty as I have experienced first hand.

[Tony Brooks]

1 hour ago, Flyboy said:

I fully agree with you on this one. I don't of any narrowboat engine that will suck up fuel without a lift pump. They will run on gravity feed though even if the electric pump is faulty as I have experienced first hand.

For information:

My Bukh and many Ford XLDs have a Bosch Rotary Injection pump with an internal transfer pump and on vehicles often do not use a lift pump. My Bukh does though.

 

The DPA also has an internal transfer pump. This and its derivatives are used on BMC & some Perkins engines. I doubt these transfer pumps would self prime but once full of fuel I expect they would draw fuel from the tank except ant effective suction they produce would just as readily suck air back down the leak off pipe via the small drilling in the banjo bolt on the fuel filter.

 

7 hours ago, Tony Brooks said:

Very hookup to be proven wrong on this.

 

What the blazes is going on I am sure I typed HAPPY and as far as I know there is no auto-complete on my computer!

[ditchcrawler]

2 hours ago, Tony Brooks said:

 

 

What the blazes is going on I am sure I typed HAPPY and as far as I know there is no auto-complete on my computer!

If your like me you are thinking one thing and typing something else, so what was Jenny saying about the electrics while you were typing?

[Tony Brooks]

[WJM]

Just to follow up on this - I had the fuel pump replaced last week. This weekend I did about six hours running, most of it running hard on the tideway and... no recurrance of the problem. Fingers crossed, I hope the problem is now solved.

 

 

[Muckyduck666]

Hi all . I've just joined too say thanks for the advice you gave on the izuzu engine running troubles. I knew mine had a diesel problem started then a few minutes would cut out . I changed the filters and it still ran the same. Even ran it out of a can still the same. Unplugged the main wiring loom put it back and job done after weeks of head scratching.  Cheers 👍👍

[Jen-in-Wellies]

8 hours ago, Muckyduck666 said:

Hi all . I've just joined too say thanks for the advice you gave on the izuzu engine running troubles. I knew mine had a diesel problem started then a few minutes would cut out . I changed the filters and it still ran the same. Even ran it out of a can still the same. Unplugged the main wiring loom put it back and job done after weeks of head scratching.  Cheers 👍👍

Welcome to the forum. Great to hear it's been of use in solving your engine problem.