MMCd 1.8 log help

[Baron4406]

Ok getting back into DSM's here and it appears I never used MMCD 1.8 before, this version has a lot of things that are pretty cool.

First off I set the car up, its a '93 AWD with a very healthy JDM 6 bolt. Full 3" exhaust, Evo 580 injectors, tubular exhaust manifold, big FMIC, blow thru MAFT, big 16G. So right now just want a quick street car nothing fancy, gonna try to get 17-18ps boost.

So after a lot of hemming and hawwing around, got a good log. Tuning with a MAFT is hardly accurate and yea I need a wideband. At 6300 rpm's I got 1-2 counts of knock, 91% INJd, 23 deg timing advance. Ok I probably need a better fuel pump for one the injectors are working too hard. What has me stumped is the O2 readings, I don't have a rear sensor so its understandable that one is reading 0, its the O2-R right? However the O2-F is stuck at 2.5 to 2.67v for all my logs.

First off the scaling for a narrowband O2 is 0-1v, how can it be reading that high? Does indicate a bad 02 sensor? My gas mileage is pretty horrible, however the ECU is throwing no codes. Very strange!

Any help would be appreciated

 

[Baron4406]

Ok no one wants to tackle this one . Here's more info.

Since my O2-R readings are 0.01v on my logger at all times I dug out the ECU and decided to measure the voltage right at the C-61 connector pin #4. Its a constant 4.56volts!! I thought the narrowband sensor read from 0-1v???? In fact its 4.56v without the car even running, with the key just on.

I had a lot of hacked up ECU wiring from an SAFC install by a previous owner, I noticed something weird also. The O2 sensor wire comes in to the ECU in a brown shell with a white stripe, there is shielding around the O2 wire which is mated with two black wires that disappear back into the wire harness, they are also linked up with a black wire that is connected to the shielding of the Detonation sensor wire #9.

WTF is going on here? Whats strange is the car runs great at part throttle and its throwing no codes. How can that be with all this weird stuff going on?

 

[maddog_187]

as far as logging with the mmcd you don't need the o2-f it means nothing you will be looking at the value on the o2-r I read this early but will have to look and try to find the post again.

Okay found it: This is a quote

"I assume this is from MMCd. The actual 1G O2 sensor is O2-R not O2-F like you would expect. So the value is meaningless.

Only California cars and I think 94's have a EGR Temp sensor. You don't need to log this."

 

[steve]

It might be helpful to the OP if you provided a link to where you found that quote. There is other information for him in that thread.

http://www.dsmtuners.com/forums/newbie-forum/361392-hard-start-rough-idle-data-log.html

 

[maddog_187]

That is true I was in hurry and didn't think of it. I will remember next time

 

[Baron4406]

I know I don't need the O2-F reading, I was wondering why my O2-R reading was 0V in my logger and at my ECU the O2 wire is reading 4.5v and no trouble codes.

 

[steve]

I know I dont need the O2-F reading, I was wondering why my O2-R reading was 0V in my logger and at my ECU the O2 wire is reading 4.5v and no trouble codes.

There is no normal way the O2 wire at the ECU is going to read 4.5v, are you sure you measured the right pin? If you did then there is a bigger issue.

Do any of the other sensors values look funny?

 

[Baron4406]

There is no normal way the O2 wire at the ECU is going to read 4.5v, are you sure you measured the right pin? If you did then there is a bigger issue.

Do any of the other sensors values look funny?

Ok major brainfart...... I looked closer at the pin out and I had missed where it said "looking into the ECU at the male pins". I measured the right pin this time and yes its cycling properly at idle however the logger still reads 0v at all times. Actually makes me feel better, I knew the ECU had to be seeing something or it would throw a code. Having the logger read my narrowband O2 isnt that important anyway, I'm gonna feed a wideband signal into my logger soon.