motronic question

[lennon]

This will probably seem like a stupid question to someone intimately familiar with how the DME works, but that's not me.

What is going on when running no o2 sensor in a motronic 1.3 system with a performance chip (Mark D) for 2.7i? I guess Mark writes a new set of "closed-loop" (proper term?) values to run off of, and I'm not running on stock 2.5 values, right? How many of you aren't running o2 sensors? I'm looking for any input on the topic of no o2 sensor with aftermarket chips.

I know, an o2 sensor is cheap. I've just been running without one for a few weeks and I cant help but wonder what's going on without it. It seems to run a little rich just like a stock chip with no o2 sensor. I've run plenty of cars without o2 sensors for varying reasons/durations. I'm just curious if anyone knows how Mark D or others set up their chips.

my flame suit is on...

[5KWattson]

I belive European cars default lean not rich when you are throwing a CEL or emissions device is not hooked up, but I'm not 100% sure

[lennon]

well my e30s (USA) always smell a little rich without an o2 hooked up. now with the bad one hooked up...who knows. defaulting to rich seems like it would be the safer thing to do...

but i am here asking questions so what do i know.

[5KWattson]

Dude the car is a German made car...that's what I meant. They default lean, I know that rich is safer but for some reason if I remember correctly they go lean, What to do.....hmmm buy a new one? Hook up a good one? Sell your car?

[lennon]

dude did you even read my post? im not asking WHAT TO DO. obviously i need a new o2 sensor, dipshit.

im asking for some explanation of the common way of writing these chips in reference to open and closed loop, with/without o2 sensor, etc. mostly out of curiosity.

i like your broad sweeping generalization of how all "european cars" fuel injection systems work.

if you dont know any helpful information, why reply?

[Danny]

Well, if I understand what you're asking...

"open loop" is a safety measure, to prevent detonation the Motronic ECU runs rich, when it can't tell how much fuel is in the exhaust (no o2 sensor)

[lennon]

thanks for a decent response danny. yeah, i understand that. i'm just curious if mark d's chips or others respond the same way to having no o2 sensor. both "open" and "closed" loop maps are defined by that chip, right? as in- it doesn't revert back to some map somewhere else in the stock DME for no o2 sensor, right?

[Danny]

Right, and of course the open loop is going to be different for a 2.7i! Its a different motor, friend.

[lennon]

alright. stupid question on my part i guess. i was worried i might be somehow driving around on stock 2.5 maps because of my lack of o2 sensor input. i didnt think mark d would set it up to leave me hanging like that though. i need to spend some time studying how the DME works.

[5KWattson]

look asshole, i know it was a broad statement, the point was as i was informed "european cars default lean" as i was informed. as stated about/\/\/\/\ "im not 100% sure" fuck off i was just attempting to help out a bit...maybe save your dumb ass from fuckin up your motor if they do happen to run lean which i guess they dont...but why the fuck dont you buy a o2 sensor, instead of tryin to flame me for offering some sort of advise, and stop wondering about shit that you have no control over...you dont write the chips you never will so why the fuck do you care? are you a tuner? god i hope not