Why don't Euros have 02 sensors?
#1
Rennlist Member
Thread Starter
Why don't Euros have 02 sensors?
I understand cat converters are not necessary but why not 02 sensors? Isn't feedback of air/fuel mixture a good thing to for power/effeciency/stochio?
#3
Official Bay Area Patriot
Fuse 24 Assassin
Rennlist Member
Fuse 24 Assassin
Rennlist Member
L-Jet and LH cars have a preset fuel map from the factory that has been dialed in for ideal stoichiometry. However, the computer is highly dependent on MAF signal and voltage. If the slightest bit of voltage were to decline due to age of the MAF, it will cause running issues. However, I found that Euro LH coded cars run a bit richer at WOT than a US LH car when the O2 sensor is ignored when hammering the go-pedal.
#4
Rennlist Member
Thread Starter
Not on CIS. Why not on a later, sophisticated LH system like my '85?
#5
Rennlist Member
Thread Starter
L-Jet and LH cars have a preset fuel map from the factory that has been dialed in for ideal stoichiometry. However, the computer is highly dependent on MAF signal and voltage. If the slightest bit of voltage were to decline due to age of the MAF, it will cause running issues. However, I found that Euro LH coded cars run a bit richer at WOT than a US LH car when the O2 sensor is ignored when hammering the go-pedal.
#6
Nordschleife Master
Euro LH cars have a pot to set I think CO or CO2. The Euro brains don't even have the circuit to read an O2 sensor if you wanted to add one, you have to switch to a US brain.
I don't have a clue on the WHY Porsche did it that way, but my guess is that it wasn't technical, maybe something about perception of any kind of smog control as "bad".
I don't have a clue on the WHY Porsche did it that way, but my guess is that it wasn't technical, maybe something about perception of any kind of smog control as "bad".
#7
Rennlist Member
Thread Starter
So in theory you could fine tune it with a tail pipe sniffer?
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#8
Nordschleife Master
Not some much fine tune as set the idle characteristics, since wot runs out of the tables and I think ignores both pot and O2 sensor. Real tuning, SharkTuning, is measure with a wideband o2 and burn new chips.
#9
Nordschleife Master
The "euro" LH and EZ-K ecu's are identical to the US ones, including the chips. The difference is the coding plug tells the ecu to use a different fuel map and inputs to govern idle speed and base mixture.
I've switched a couple of my S4's between using O2 sensors and not using them - the harness plug exists, and the only change needed is to swap coding plugs, plug in the O2 sensor, and unplug the 3-pin connector on the potentiometer.
The addition of the O2 sensor only changes idle and low-load cruising mixtures, to meet local emissions regulations - under high load conditions or wide throttle all 928's run open loop and use the same fuel map.
I've switched a couple of my S4's between using O2 sensors and not using them - the harness plug exists, and the only change needed is to swap coding plugs, plug in the O2 sensor, and unplug the 3-pin connector on the potentiometer.
The addition of the O2 sensor only changes idle and low-load cruising mixtures, to meet local emissions regulations - under high load conditions or wide throttle all 928's run open loop and use the same fuel map.
Euro LH cars have a pot to set I think CO or CO2. The Euro brains don't even have the circuit to read an O2 sensor if you wanted to add one, you have to switch to a US brain.
I don't have a clue on the WHY Porsche did it that way, but my guess is that it wasn't technical, maybe something about perception of any kind of smog control as "bad".
I don't have a clue on the WHY Porsche did it that way, but my guess is that it wasn't technical, maybe something about perception of any kind of smog control as "bad".
#10
Rennlist Member
Thread Starter
Mine has added-on wires from the ecu leading to where the 02 would be. Maybe the importer did the mod to pass emissons at one time. My part-throttle, low load cruise seems lean but I have no idea how I would check that.
#11
Nordschleife Master
My post above was re: LH 2.3 (928's from 87-95). Pretty sure you don't have an O2-loop capable ecu, instead you're supposed to adjust the MAF to a known value which determines mixture for the cats.
#12
Rennlist Member
Jadz928's former 84 Euro has a wideband sensor installed. And some modifications to the ECU to allow it to be sharktunable. Maybe he will weigh-in to explain it.
#15
Drifting
https://rennlist.com/forums/4737979-post3.html
https://rennlist.com/forums/3369822-post6.html
https://rennlist.com/forums/928-foru...rs-beware.html
keywords - O2 sensor, LH brain, open loop, federalization, euro, impedance, brain,
https://rennlist.com/forums/3369822-post6.html
https://rennlist.com/forums/928-foru...rs-beware.html
keywords - O2 sensor, LH brain, open loop, federalization, euro, impedance, brain,