Unusual Lambda Problem

[marcus1970]

Start car up and seems to run reasonably well. However, as the car heats up the MIL light starts to come on intermittently.

When plugged into the laptop it shows a lambda 2 fault of 1.8v. The unusual thing is that the MIL light comes on when I'm accelerating or using constant throttle, but when I ease off and the car goes into overrun / engine breaking, the lambda goes off until I again press the accelerator.

I'm stumped about this.

Any ideas?

MB

[Mike Hawthorn]

While I've not had this problem (yet) I'd guess a good starting point would be to swap them over (The lambda's that is not the wiring)and if the fault goes to No 1 side then "Hey presto" if not the the problem is somewhere up stream. As I remember the Lambda's are not that difficalt to get at once the car is up in the air.

[marcus1970]

Forgot to say, they are both new, having both been replaced a week ago by a TVR guru, so they should be in tip top condition and fitted properly.

MB

[Toadusmodus]

Looks like the problem I had, ended up swapping the entire engine loom and new lambdas to cure it in the end. Make sure you don't have water in the connection in the loom under the expansion tank (if your car has the early type loom).


http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[GreenV8S]

marcus1970 said:

Forgot to say, they are both new, having both been replaced a week ago by a TVR guru, so they should be in tip top condition and fitted properly.

MB

I wouldn't take anything for granted. Given that work has been done here recently, this is an obvious suspect. For example if the lambda connections have been crossed over by accident, they would probably diverge very quickly in closed loop operation which may be what your fault light is telling you.

[ngr]

Also worth checking the ecu main plug. I had one car with water ingress in the footwell which caused plenty of intermittent lambda faults due to bad corroded/damp connections on the ecu itself.

[marcus1970]

ngr said:

Also worth checking the ecu main plug. I had one car with water ingress in the footwell which caused plenty of intermittent lambda faults due to bad corroded/damp connections on the ecu itself.

No problems with the ECU it's dry as a bone and corrosion free...

MB

[marcus1970]

GreenV8S said:

marcus1970 said:

Forgot to say, they are both new, having both been replaced a week ago by a TVR guru, so they should be in tip top condition and fitted properly.

MB

I wouldn't take anything for granted. Given that work has been done here recently, this is an obvious suspect. For example if the lambda connections have been crossed over by accident, they would probably diverge very quickly in closed loop operation which may be what your fault light is telling you.

Had both connectors out yesterday and they are definitely not crossed over - each one goes to the correct bank and they seem in good working order...

MB