Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 4/4 Sigma Injectors issues today - solved.

Today I had a little tour with the 4/4 in the best weather. In between, I went for a walk in the countryside. When I came back and wanted to start it, only three cylinders were running. Luckily I have my OBD2 with me. It showed error code 202, indicating that one of the injectors was not getting any control current. It was injector no. 3. Luckily I had some electrical contact spray on board. Funnily enough, after spraying, injector no. 2 was without power. I pulled off all the in injectors in turn. In fact, the OBD2 was able to identify each injector by number.



I cleaned all the contacts of all the injectors. I had to wait about 30 minutes until all injector contacts were dry and working again because I had no compressed air on the road. And blowing was not strong enough. Before this 30 minutes and after spraying in front of time she runned on one cylinder only.

In the end, the car was running properly on all four cylinders again. The pictures show how much the contacts had oxidised after six years and 92,000 km.

One benefit: After cleaning the contacts, the engine sounds much quieter and smoother. It pulls even better, has a bit more torque and is more greedy for high revs.
With the light 4/4 you notice every single horsepower. My guess: Until now, the engine ran on all four cylinders, but the contacts were already very bad. Maybe they had a higher contact resistance so that the injectors didn't open and close completely as well and as quickly. The sound of the engine after the treatment is as if it was tapered.

One of the plugs before cleaning when running on three pots only...underway.



and the corresponding oxidised counterpart of the plug.



after spaying the plug and the counterpart...and waiting.



Why I am sharing this...it is always good to have an OBD2 on board before you have hundreds of other suspicions. It helps to narrow down the fault significantly.
And secondly, if you have been driving a 4/4 for several years and also wash the car or drive it in the rain...it is worth unplugging the connectors and cleaning the contacts. The engine sounds better, runs tighter up to high revs and is quieter.
These plugs are always exposed to the elements, even if they have a rubber coat. So why wait after several years until a cylinder fails, and this could apply to all modern injection engines. Plus 4 and Roadster as well. The plugs of the injectors are more or less the same.

She looked so cute when she stopped running.

Nice find Heinz.

Great information, in cause my MOG is a little bit magnetic about rain.

René

Good advice Heinz , and with the wet stuff never far away in the UK especially its possibly a case of de humidifier out of its box and switched on in the garage !

Great result Heinz . As well as contact cleaner the action of making then breaking such connectors can clean the conducting surfaces.

Great find Heinz,
That'll be something new for Facebook to complain about, now we're either greasing our suspension or cleaning our connectors

Excellent result Heinz. Your OBD is showing how useful a tool it can be and paying for itself.
The dirty/tarnished contacts can be quite common on a Morgan due to the age and exposure the contacts are put under.