Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 3.9 v8 cuts out at bottom of a hill

How are the connections to the fuel inertia cut off switch? It sits above the wiper motor & I just wonder if there is a poor connection at a certain angle of the car.

That’s an interesting thing to check, thanks John v6. The car was delivered on a trailer in torrential rain and I had been wondering if getting so sodden could be causing issues on a connection somewhere, likewise digging further on the speed transducer box that Teknome mentions I read that they can be poorly earthed so I was going to check that too... when I can find it!

It may seem a silly question, but is there any water in your petrol tank? My brother-in-law had a Jaguar SS100 (Suffolk) that developed similar symptoms and it turned out to be due to a gallon a water at the bottom of the tank. It had not been stored out of doors. Just a thought ...........

The Road Speed Sensor can be tricky to find, on my 94 +8 it is tucked away inside the firewall above the transmission. The only way I located it was by following the speedo cable, I had the same issue stalling when coming to a halt it was a poor earth to the road speed sensor. I find most issues are earth related.

Still got the problem unfortunately.

I’ve had the ecu out, checked for water ingress, non showing, pins all ok but I cleaned them anyway with deoxit (I use this on my hifi kit) and dusted with wd40 just in case.

I’ve had the road speed sensor off, emery clothed the chassis and the Just nut on the bolt to make sure it’s a good ground, wd40 too.

The car is fine until I put it down a long steep downhill and then stop at the bottom, and there it stops.

I read somewhere that low oil pressure can knock out the fuel pump, I tried watching the pressure tonight but it didn’t give me an obvious reading to confirm a big drop.

Frustrating, but at the same time entertaining trying to find the cause.

Stepper motor?

This is an interesting issue. Maybe a long shot but I wonder if it is a fault with the inertia cut out switch seeing it only occurs when going down a steep slope and then restarts when on the level? You could try by passing the switch and see if this makes a difference!!!!

Were the bonnet louvres covered when transported? I've had no end of random idle running, rough running and stalling issues after torrential rain, where the water puddles in the injector wells, and takes a long (sometimes a days travel) time to steam off. If the injector mounts have damp in it could be level sensitive.

That is what I think too

That’s interesting, I’ve found a pic of the inertia switch on melvyn Rutter but I don’t recall seeing that in my inspections, can anyone tell me where to find it?