do autothority chips use data from the o2 sensor?

nynor · 09-20-2010, 11:04 AM

i've searched here and elsewhere for this information, but i cannot find anything definitive.

i am trying to smog my car and it is failing due to running rich. it fails by a very small margin on the hydrocarbons and carbon monoxide. it is very very close, but not quite good enough.

as it sits, i have a wideband o2 sensor and nothing is giving o2 sensor information to the DME, just to the gauge.

thanks!

J1NX3D · J1NX3D's Garage

i think chips all work the same way, have a look at frwilks dme site

flash968 · 09-20-2010, 12:16 PM

as far as i know, all chips take readings from the O2 sensor via the DME, and adjusts the mixture accordingly - without that, it would run rich under any sort of load

i know this is the case with the 968, and it does so continuously, and at most every half second - i am pretty sure it is the same or similar with the 944

floyd would be the one to ask though

nynor · 09-20-2010, 01:49 PM

thanks for the replies. i hooked up the wideband to mimic the analog narrowband to the DME. it was obvious that the mixture was different.

the car passed emissions with flying colors. however, i didn't like the A/F mixture readings and the throttle response seemed much more sluggish, so i disconnected that wire. i can put it back very easily next year for emissions.

like i said, it was VERY close to passing like this. with the wideband talking to the DME, it passed but the NOx numbers doubled to 600 (passing is 1800). so i am going to leave it like it is, except for emissions testing.

nynor · 09-20-2010, 01:51 PM

Quote:

Originally Posted by flash968

as far as i know, all chips take readings from the O2 sensor via the DME, and adjusts the mixture accordingly - without that, it would run rich under any sort of load

i know this is the case with the 968, and it does so continuously, and at most every half second - i am pretty sure it is the same or similar with the 944

floyd would be the one to ask though

unless i am mistaken, frwilks' chips ignore the o2 sensor as do the ROW DME's.

looneybin · 09-20-2010, 04:16 PM

Quote:

Originally Posted by nynor

unless i am mistaken, frwilks' chips ignore the o2 sensor as do the ROW DME's.

that is correct

flash968 · 09-20-2010, 05:32 PM

i am almost certain that the ROW 968 uses an O2 continuously, the same as it does here, however they don't have the connection to the check engine light - i'll verify that though

the only exception i have found is in south africa, where there is a cat delete option

nynor · 09-20-2010, 05:35 PM

i think, with all due respect, that you are wrong. i had a ROW DME in my 83 944 and i know, for a fact, that it ignored the o2 sensor.

J1NX3D · J1NX3D's Garage

my RoW is cat-free also, new in New Zealand

flash968 · 09-21-2010, 04:47 AM

i just confirmed it - the ROW 968 has an O2 sensor and cat, and operates exactly as the US cars (except for those cars that came cat delete, which were extremely rare)

the 944 may well be completely different though, and it may even have changed over the years it was made - i really don't mess with that car much, so i don't know about it when it gets down to stuff like that - heck, ROW 944s could have an entirely different DME or chip

nynor · 09-21-2010, 05:45 PM

ok, the 968 must be a different animal, with regards to the 02 sensor and such.

pontifex4 · 09-22-2010, 07:23 AM

You probably have the answer you needed already, but my research suggests that 951s use the O2 sensor between idle and 2/3 throttle. Past 2/3 throttle, the DME switches to the WOT map, and bypasses the sensor.

Edit: sorry, that should have read, "my research suggests that, like the factory chips, APE 951 chips use the O2 sensor..."

nynor · 09-22-2010, 10:22 AM

that sounds right. the A/F mixture i was seeing at idle and part throttle, regardless of RPM was high 14's to low 15's. at WOT, the mixture seemed the same as with the O2 connected, about 11.2. i like it open loop better, with ratios of high 13's from idle to part throttle.

smokin_944 · smokin_944's Garage

Quote:

Originally Posted by nynor

i think, with all due respect, that you are wrong. i had a ROW DME in my 83 944 and i know, for a fact, that it ignored the o2 sensor.

You may be right for ROW cars but I have an 84 car and the DME definitely responds to the O2 sensor. I'll explain. From the time I bought the car, I drove over 60,000 miles before I changed my O2 sensor and I always had a gas smell in the car (that wasn't due to faulty rear seal). I replaced the sensor a week ago, the awful smell of gas is gone and the idle and performance of the car has greatly improved. Man am I happy!!

nynor · 09-22-2010, 02:10 PM

Quote:

Originally Posted by smokin_944

You may be right for ROW cars but I have an 84 car and the DME definitely responds to the O2 sensor. I'll explain. From the time I bought the car, I drove over 60,000 miles before I changed my O2 sensor and I always had a gas smell in the car (that wasn't due to faulty rear seal). I replaced the sensor a week ago, the awful smell of gas is gone and the idle and performance of the car has greatly improved. Man am I happy!!

um, that is what i have been saying.