1 tank of petrol in about 70 miles!!!

[Deano 4.0 Chimp]

Gents,

Needing some guidance...

My daily grind decided to throw a fit last week so I had to use the beast to go to work (not used it in two months). Filled up with petrol and drove the 22 miles to work, on the way home from work the car cut out but I did not think to much about as it has done it before. The follwing day I go to work again and this time it cuts out twice and starts to run a bit lumpy..

After finishing work this night I start the car up and cannot believe that I have used a whole tank of petrol... in approx 70 miles!!! I Make it to the local garage fill up and start my way home...The car cuts out 5 times on the way home, as I get closer to home and every time I put my foot down I see some smoke..its not white and the temp gauge is fine so I assume its not a Head Gasket failure...I crawl home...

Today I went to have a good look at the car...I started it up and the bellow of black smoke was unbelievable...My Garage wall is covered in soot, when squeezing the throttle cable the smoke belches out..The term running rich is an understatement my nostrils were burning...I check around the engine bay and I have found a split in the Y piece along the top seem about 2 inches long...

I am wondering if this has caused a problem with the lambda sensors, hence why its overfuelling. So do I just get the split welded up? Check the lambda's or just change them anyway and what about the main cat, could it be fubarred?

Can a small split like this cause all this grief??

any other ideas comments are certainly welcomed!!!

Car is a 1994 4.0 Chimaera.

Deano...

[raceboy]

I had the same kind of mpg when my Lambda's went pear shaped, and the diesel like clouds of black smoke, I didn't have any issues with the cats dieing, not then anyway, but I didn't have the split in the Y piece.
I'd get that fixed and see how it runs, if it's still bad then change the Lambdas.

[Deano 4.0 Chimp]

Raceboy...Thanks for the quick reply..

[CLN1]

My mates Griff 400 had the same symptoms last year and it turned out to be the Air Flow Meter.

Colin.

[blitzracing]

As above, check the airflow meter connections. The actual air flow meter are pretty easy to test if you have a test meter and hair dryer to hand (on cold). Remove the airflow meter from the pipework, but leave it connected. Then put a test meter on volts across the red/black (earth) and blue/green wire (airflow output), and then blow air into the intake with just the ignition on and the voltage should rise buy a few volts. Loss of a lambda probe is hardly noticeable as it runs the fixed fuel map without the lamda corrections only and you might lose 3 or 4 mpg. No more. Dumping unburnt fuel into a hot cat' can melt the core that effectively block the exhaust, so if you still have problems after you find the rich running, look at the precats.

Mark

[mdotrutherford]

Something else to check out is the ECU Water Temp Sensor - may have failed and ECU thinks engine is cold and overfuelling.

[blitzracing]

Thats true, but only in open loop above 3/4 or so throttle or 3500 rpm. Below this the Lambda probes just keep pulling the mixure back, even if the sensor inputs are significantly wrong.

Mark