running too rich. .

My 4.6 P38 failed its mot as the tester said it is off the scale running too rich. . . The smell of fumes coming through the exhaust in the garage made your eyes water. .
I took it to a Land Rover Garage to get the proper computer on it to see what was the problem. The computer could not pick up my ECU and the guy said this is not uncommon, there is a problem with the wiring from the diagnosic plug to ECU.
So i still have not sorted the problem. I have put in new plugs and so leads maybe the next step as i do think there is a slight miss on tick over. Also the tick over does seem to be low until warm, so i am toying with the temperature sensor too although not sure whih it is the blue or brown next to the alternator?

Any help will be most grateful
Thanks

Loo-knee said:

\I took it to a Land Rover Garage to get the proper computer on it to see what was the problem. The computer could not pick up my ECU and the guy said this is not uncommon, there is a problem with the wiring from the diagnosic plug to ECU.

Click to expand...

Never heard of it. I mean sure it could be but far more likely is a problem with his diagnostics. That is common, even on Testbook. Is it only your car's ECU it cannot read? Did he try cleaning the connectors in your car's socket?

I will have to contra Rasheed and say it's far more likely to be your diagnostic socket at fault. They are prone to corrosion and I have read many threads about problems with these. Your rich running problem is more than likely to be a failed MAF or 02 sensors. If you change either of these things you need diagnostics capability to reset the fueling adaptions afterwards. I would start by getting the socket sorted then this will allow you to get a reading from your maf which can then be checked against some known good readings.

rewmer said:

I will have to contra Rasheed and say it's far more likely to be your diagnostic socket at fault. They are prone to corrosion and I have read many threads about problems with these. Your rich running problem is more than likely to be a failed MAF or 02 sensors. If you change either of these things you need diagnostics capability to reset the fueling adaptions afterwards. I would start by getting the socket sorted then this will allow you to get a reading from your maf which can then be checked against some known good readings.

Click to expand...

Not to worry Rewmer.

I've never heard of a wiring problem specifically between the socket and ECU. You'll note I did ask if the port contacts had been cleaned although in fairness one would hope a main dealer's garage doesn't need to be told that. And why I said T4 failure is not unheard of is that my local main dealer's system recently had a problem where it simply couldn't connect to any vehicle including mine. They had to send it back to the UK for some kind of repair and are using a back-up online thingie for now (anyone heard about this by the way?).

Agree with you re MAF and 02s. Easy test of Maf is to unplug it while the car is running and see if anything changes.

Further to that,T4 is very reliable - more so than the cars it talks to.Besides the 16 pin sockets corroding there is also a 5 way splice that corrodes and will stop comms with everything except the EAS ecu from memory.The splice is in the loom below where the heater matrix o rings leak - you can guess what happens.
Going back to the OP, T4 is only going to confirm its running too rich as a result of missfires,so its not really needed anyway - what is needed is someone to locate the cause of the misfire,which is basic diagnostic work.