Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) ARP4 issues

I have the engine light on in my ARP4. Apparently, there has been one other ARP4 with the same issue. Turns out it was the "barometric pressure sensor".

Mine is in at Brands Hatch Morgan for diagnosis on Monday 21 March. I will report back then.

OMG not the dreaded Barometric pressure sensor

You are lucky, all that heavy air, someone could have died!



(whispering) What is it?

The ECU can use the barometric pressure (i.e. the density of the air) to calculate exactly how much air is going into the engine by combining it with the flow rate data from the MAF sensor. It can then adjust the mixture appropriately to cope with air density variations as the car gets driven up and down mountains for example.

If the measured barometric pressure falls outside a preset tolerance, then the ECU could set a fault code maybe?

I don't think there is a MAF sensor on the ARP4. In my case, with the Omex throttle bodies the barometric pressure sensor was optional but I chose it because we often go up over 1,000 metres above sea level. To be honest I don't think it makes much difference as the sonda lambda feedback loop controls the mixture. Mainly it is there to compensate for altitude changes, there is however a pre-set adjustment to fueling that is used when the barometric sensor is activated. I am sure that it will be the same with the Cosworth setup.

A malfunction of this sensor would not be much to worry about in the UK (no high mountains). It will turn out to be a faulty sensor or a bad wiring connections and shouldn't cause any huge concern.

interesting!

let's hope it is something simple.

Plug fell off maybe?

The Rover T16 measure the inlet manifold pressure. The sensor is in the ECU & air comes from the manifold after the throttle body. Oil from the engine breather can therefore foul the sensor

SFO,
I would suspect far to much heavy breathing due to over excitement driving the AR-P4.
Good luck to you

:-) Reminds me of a trip to Austria a few years back. I was in my Elise, heading up Grosseglockner.
The Elise didn't have a barometric sensor, and was losing power to the extent that near the top I was being overtaken by bicycles!

One or two other things I have noticed is that the water temperature seems to run very cool at between 70 - 80 degrees, which seems very low to me, and has anyone found a dimmer for the instrument lights yet?