Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2010 4/4 engine power loss

Those switches are not expensive. I would change it anyway

Just be careful.

The switch concerned is right next to the brake light switch. One is Normally Closed and the other Normally Open

I think that the brake light switch is normally closed and is held open (i.e off) by the brake pedal. Please check though - I labelled my spares and locked them in the foot locker - no time to find them and check now.

My hypothesis is (as yet unproven) that the ECU signal that the switch operates is very low current - below the wetting current of the switch which, in time, corrodes and becomes intermittent,

Picture of the switches here on my 4/4 I sold. It was the brake switch that failed on mine

I took similar pictures, but due to old leaves from last fall and a lot of dust, the switches were not very visible.

Well, after much thinking, scratching heads and nothing from the OMDB2 diagnostic I took the car to a British car specialist in Sydney and we both agreed that my initial reaction of feeling just like fuel starvation was likely the problem. After a huge amount of work to get to the fuel tank through the internal storage area and removing the top wooden strut (luckily screwed, not glued and screwed) they accessed the tank. Mine is the Sport model, I assume those with a spare wheel will have easier, external access? The fuel pump is an internal model. The body of the pump was completely rusted through and the scrim/filter at the bottom of the pump was full of rust - we had found our culprit. I suspect a victim of me not keeping the tank full of fuel - I had become complacent that being an aluminium tank it wasn't going to rust. My fault, I hadn't considered the steel bodied pump! When depressing the accelerator and asking the pump to work harder the rust obviously was blocking the flow. The part number referenced it to a Mazda part, but we replaced it with a Bosch alternative. The fuel lines were checked to make sure there was no rust anywhere else in the system. They emptied the tank and checked it was perfectly clean. 8 hours labour and a new pump later it is an expensive, awkward fix. The fuel filter is certainly not an easy maintenance item! The good news, is that it now drives like a new car - I'd gotten used to the fuel starvation even at lower rev's limiting the performance. Thanks for all your ideas and thoughts.

Great news.....

Martin, Isn't it funny how when you first posted you were describing fuel starvation, Shows we should go with our gut instinct! Yeh, it's a Morgan so we all tend to look for the impossible answer yet it is just a car. The lesson learnt here to all should be not to accept the fuel check at the point of delivery as "yep, we've got fuel"!

That is excellent news.

I'm not sure of the electrolytic rules, but I wonder of an alloy tank would accelerate corrosion of ferrous parts in the system, like the OP's fuel pump ?

Thanks for sharing both your foible and perhaps more importantly it`s fix, which seems likely to help others similarly affected in future...

I find myself questioning as to why it seems fuel pumps became fitted within the tanks, as opposed to externally.

At a guess given early fuel injected sports cars such as the TR5/6 had issues with overheating pumps causing a degree of fuel issues, perhaps caused others to think of submerging the pumps in the fuel for cooling purposes...?

70`s fuel injected Porsche 911`s seemed to have no notable issue with electrical pumps mounted outside the fuel tank, though as best I can remember they were fitted approximately level with the pickup point of the fuel tank.. at the front of the car and likely exposed to quite some degree of airflow..

Since the arrival of EFI and digital control, the diagnosis of issues has become ever more complex even for professionals, unless the fault without any code generated, or a random code, was previously found, repaired and the cause recorded/remembered..?