Fuel starvation issue

[Hans]

A fuel leak has been repaired by my local garage by replacing a small section of the fuel pipe which feeds the engine from the main fuel tank. They told me the replaced section is about 1 inch or so.
Since then the cruiser displays the following symptoms:

1. Always when accelerating up to and reaching approximately 2200/2400 rpm the car starts to shudder. When I reduce rpm the engine runs fine again but sometimes (not always) very shortly after that will start to lose power and the engine will cut out altogether.
2. On 2 occasions, when the car has been parked overnight, I am able to drive perhaps 100 yards or so before the car suddenly cuts out even though I didn’t rev up to 2200 rpm.

For both symptoms I can restart the engine using the main tank. Start-up is initially rough for a few seconds and then idles back to normal.

I have an auxiliary fuel tank installed with feeds the engine separately. I select between the 2 fuel tanks via an electrical switch. None of the above symptoms occurs when I drive using the auxiliary tank. Revs up nicely beyond 2200 rpm and no cutting out whatsoever at anytime.

I initially thought that perhaps some dirt got into the fuel filters when they fixed the pipe but as the engine runs absolutely fine from the auxiliary tank then I guess that should exclude it. I also suspected that the section of pipe they replaced was perhaps of a smaller diameter than the original pipe but when I discussed this with the garage they said that this wasn’t the case and the diameter matched that of the existing fuel line.
Could it be possible that the replacement section isn’t sealed off properly and somehow air is sucked into the fuel line as the rev increases, assuming this would cause a problem like this?
But then why on a couple of occasions would the engine stall after a 100 yards or so when it has been switched off for some time and without reaching those revs?

I have driven about 100 miles since the pipe has been repaired. The main tank is about half full. The car is going back in the garage on Tuesday as they have agreed to have a look at it but I have not much confidence that they will fix it especially as they have already set the scene by stating that they only replaced the leaking section and haven’t touched anything else and so “it must be another fault that has suddenly developed” !!! Needless to say that the car drove absolutely fine before it went into the garage.

Is there anything else you guys could think of that may cause this problem after such a repair?

Cheers

 

[StarCruiser]

Sometimes the end of a piece of flexi pipe can be pushed over when fitting which could cause a restriction and possibly air leak. If they’ve used a hacksaw on the pipe instead of pipe cutters then swarf could have got in possibly lodging in your change over valve if that's downstream like it sounds like it is. Also if they have used pipe cutters they will restrict the pipe requiring the internal burr to be removed. I’d look at it myself if I were you and take photos of what you find. If clips aren’t done up fully, allowing air in then you could get symptoms like you describe also.

Good luck with it and let us know how it goes. There is a tank filter sock which can cause this. As it’s only started since the garage did the work I doubt it is this. It can be blown back with air to clear as a trial measure.

 

[Hans]

Thanks very much StarCruiser. I will check it out and see what happens on Tuesday.

 

[Hans]

Well, I went back on that Tuesday and managed to speak with the mechanic. It then transpired that the replacement section was indeed of a smaller diameter. He agreed that at the higher RPM (2200+) the engine wasn’t probably getting enough fuel hence the symptoms. They decided that the best course of action was to replace the fuel hose altogether with the correct diameter.

It was finally fitted today. I received a call from the garage to say that they had replaced the hose but that the problem was still there!!
Went to pick up the car to try it out but the problem isn’t just still there, it is ten times worse. In fact I am now unable to drive using the main tank at all. It cuts out altogether even when idling. Switching over to the auxiliary tank eventually, but with great difficulty, gets me going again.

Back to the garage to find out what is going on as the car couldn’t have been road tested. Couldn't get a straight answer as to how the car was tested. They also now draw a blank as to what the cause could be as they maintain that they have only replaced the fuel hose and haven’t touched anything else.
They are calling me tomorrow with the next course of action but truthfully I have lost all confidence. If they have indeed only replaced the fuel hose why would it from running fine except above 2200 RPM to now not getting fuel at all? It seems to me that this should be a straight forward piece of work and that something was missed.

 

[Dave_S]

I think Starcruiser summed it up : a dwarf has got in there. You need to sort that...

 

[Geoff hzj75]

Hi from Aus,
Have the boffins at the garage checked the main tank solenoid (under car) if its on the wayout you'll get an restricted fuel flow or none at all.
Just a thought I would look at since your aux is fine.

 

[StarCruiser]

I think Starcruiser summed it up : a dwarf has got in there. You need to sort that...

I missed that one. Made me laugh. Bloody auto correct!!
Mind you a dwarf up your fuel pipe would certainly be a blockage.

 

[Hans]

Yeah, it made me chuckle at the time. Anyway I am working with the garage to find the little bugger.

Thanks Geoff for the solenoid option. I'll keep that in mind.