Black smoke! Black Smoke :(

[karlblues2]

Hi guys
Driving in traffic this morning and very start stop at that. The S2 would almost die, then it would shoot off with lots of black smoke exiting the exhaust. Also pops when backing off. Any ideas??
O2 sensor? TPS? Temp sensor? Fuel pressure regulator??
Cheers

[Acidburn]

boost leak i'd say, sounds like what I had with my s2.

[karlblues2]

Thanks mate. I checked all the obvious hoses before posting, but I'll check again. assuming no boost leak, any other ideas?
Cheers
Karl
Oz

[karlblues2]

Well it seems the Engine Temp Sensor is faulty! Reading -49 degrees C at idle
Hopefully that will fix it. I guess that is why it was forcing so much fuel through!!
Cheers
Karl

[prj]

At idle? Or when the car is standing still with ignition on and the engine not running?
If it is really reading it this way at idle - then yes, it's faulty.
However, if the car only has the ignition on and the engine is not running, then it's normal for it to display this.

[karlblues2]

Thanks mate. It occurred at idle and whilst switched off, so I think it is stuffed then eh?
It will be changed this afternoon. If that hasn't fixed it (fingers crossed it has) then what else could it be?
Cheers
Karl
Oz

[karlblues2]

Also the throttle position at idle is 8.7 degrees. Is this correct??
Cheers in advance
Karl
Oz

[prj]

Usually is 5-6 degrees on idle.
I would not say 8 is out of the ordinary though.
If your sensor stays at -49C all the time, then it's shot for sure and changing it should cure the problem.

[karlblues2]

Great! Thanks matey. Is it worth adjusting back to 5-6 degrees?
I'll let you know if fault is fixed later tonight
Cheers
Karl

[prj]

TPS is not that important for engine management on these cars.
If your cable has been fiddled on - I guess it'd make sense to adjust it.

Don't fix what's not broken though. Considering it runs closed-loop idle control, if your idle is fine, then no point wasting time on it.

[karlblues2]

Thank you prj
Cheers
Karl

[pasbogdan]

-49 was mine with ignition on.At iddle it was normal.Are you shure your interface was reading at iddle?or the screen was the one from the test with ignition switched on?

[karlblues2]

Maybe I need to test it again this arvo

[karlblues2]

OK Temp gauge in the car was reading 110 degrees after inserting new temp sensor.
Any ideas why?
With old temp sensor in it would read accurately at just below 90 degrees. On VAGCOM, temp reads nearer 90 degrees. All that has changed is the temp sensor. Any ideas? As it is still in the workshop, have yet to check whether it has fixed the black smoke issue
Cheers
Karl
Oz

[prj]

Didn't the gauge use a different sensor - not the same as the ECU?
I need to look at some diagrams though.

VAG-COM indication should be correct anyway. Coolant temp should be between 87 and 98 degrees when car is warmed up. The latter only if you are pushing it hard...