New scangauge, odd °fWT

[bnmorgan]

Got my scangauge yesterday, and of course like a kid with a new toy went right to installing and figuring out how to do it.

Car spec first, 2001 Beetle TDI, 1.9L

I'm all good except the MPG, which if i understand has to be tuned or calibrated at fillup, which won't happen for another 1/2 tank or so (only at 300 miles now).

Problem is, my fWT blinks something that i think is overboard, ~205-210 at highway speed, but every few seconds, it will blink just long enough to read about. at crank this morning, it showed 73/80, but they swapped places along the way. My fIA shows ~98-105, which i figure is probably about right for 85-95 ambient temp and 5-10 lb boost.

Suggestions or tips? I did search the forum but didn't come up with anything, but y'all usually know things i don't on where to find things.

Thanks.

[Arragonis]

One immediate thought that occurred reading this was a loose connection in the OBD port but then again it is digital so you would get the right signal or nothing. On my car the port is completely closed when a cubby hole door is shut so I had it going off a couple of times when the plug was nudged out.

So (another theory I'm afraid) could it be a faulty temp sensor on the engine occasionally reading very high ? That would lead to the SG2 'sampling' that value and occasionally displaying it.

You don't get a warning because the ECU is programmed to smooth those things out before reporting a fault. i.e. the ECU designers realised that physical components occasionally go wrong and they compensated for it in software.

You could ignore it or get the sensor changed - start with the cheapest bit.

[dcb]

the scangauge (and most obd solutions) only gauge the airflow and assume the mixture is reasonably close to stoichiometric , the tdi is rarely anywhere near stoichiometric and does not produce useable mpg numbers in this manner.

[Arragonis]

Originally Posted by dcb

the scangauge (and most obd solutions) only gauge the airflow and assume the mixture is reasonably close to stoichiometric , the tdi is rarely anywhere near stoichiometric and does not produce useable mpg numbers in this manner.

Don't know how that would affect temp but can I point you at my thread (steady...).

Scangauge Newbie Questions

I have a few MPG SG2 stylee questions.