Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Hi there team. Learning heaps so thank you all so much!
Ok, this is an Australian car. I am in New Zealand and have a small country garage business...
2003 BA Ford Falcon. It has a 4.0 litre straight 6. Super common down here. My question is. Looking at the scan data, fuel trims, there are two STFT readings. STFT1 and STFT2. Our number 2 reading is positive as it can be. I went looking for an air leak and indeed I did find one. I thought it would be a fix. But my numbers went straight back up there. STFT1 and our LTFT are normal. Why are there 2 STs?
I guess I could still have an air leak some where as well. There are no DTCs. This is a speed density engine. There is only one 02 above the cat. There was a crack at the cat that we have fixed. 02 readings look good.
It is almost certainly spurious , although on most straight 6 engines have the injectors split into two banks if there is only one upstream O2 sensor there can be only one short term adjustment.
My guess is the basic ECU is shared with a V8 and this is a PID that is left floating you could also be looking a B1S2 fuel trim which again is a floating value on 99.99% of vehicles.
This sort of issue is not unknown on my daily driver if I scan the ECU using manufacturer mode I get a spurious oil temperature high PID but the engine hasn't got an oil temperature sensor, the spurious reading only occurs in manufacturer mode not OBD2
Also I am pretty sure if you picked any random older Ford there is a 1 in 3 chance if you looked for at vacuum leak you would find at least a minor one,
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Topic Author
