Thread: Rich when cold

its supposed to run rich when cold, its like pulling the choke on to start an old engine. IF you mean its running excessively rich to the point that its difficult to drive and severly lacks power thats different.

The exhaust O2 sensor would be my first port of call for this one followed by the connections and harness all the way from that to the computer.

I used to have similar problems with my RR....Was just about to set fire to the bloody thing out of pure frustration - when an old bloke down the street came over and offered to help. He started with all the earth and basic wiring, and after a good clean up ( I was amazed haw fouled the earths were..) the engine was running beutifully. We also found a shot wire on the MAF lead that was earthing it out intermittantly... Problems fixed.. That may be worth a look??

I will double check all earths tomorrow, I know that the engine temp sensor works on variable resistance so I guess a poor earth will add resistance. I will let you know how I go.
Thanks.

Originally Posted by Blknight.aus

its supposed to run rich when cold, its like pulling the choke on to start an old engine. IF you mean its running excessively rich to the point that its difficult to drive and severly lacks power thats different.

The exhaust O2 sensor would be my first port of call for this one followed by the connections and harness all the way from that to the computer.

Thanks for your advice. Yes I do mean excessively rich, to the point where the engine stalls and acts as if flooded on restart. If I rev it at a very fast idle until warm all is well.
My model doesnt have the o2 sensor, I believe it was introduced in the 89 model.
Thanks.

In an 88 The Thermo Time Switch activates an additional cold start injector depending on the temperature.
It sounds like the Thermo time switch may be faulty.
It is part of the cold Air bypass, which is the cylinder thing on the front of the manifold.
To check it out, disconnect the cold start injector.
It should still start on a warmish morning, but not be too rich.


Regards Philip A

Originally Posted by Blknight.aus

its supposed to run rich when cold, its like pulling the choke on to start an old engine. IF you mean its running excessively rich to the point that its difficult to drive and severly lacks power thats different.

The exhaust O2 sensor would be my first port of call for this one followed by the connections and harness all the way from that to the computer.

Just highlighted your knowledge on rover V8's, aus spec ones don't come with O2 sensors

Originally Posted by PhilipA

In an 88 The Thermo Time Switch activates an additional cold start injector depending on the temperature.
It sounds like the Thermo time switch may be faulty.
It is part of the cold Air bypass, which is the cylinder thing on the front of the manifold.
To check it out, disconnect the cold start injector.
It should still start on a warmish morning, but not be too rich.


Regards Philip A

^^^^^^^^

Sorry, I didnt state that in an attempt to solve this problem the cold start injector has been disconnected. Starts perfectly without it (so it must be getting excess fuel somehow). I live in an area that gets some very cold mornings to.