ECUs and Tuning Discuss Engine Management, Tuning, & Programming
Sponsored by:
Sponsored by:

Stock NA8 AFRs w/ LC-1

 
Old 02-26-2017, 12:32 AM
  #1  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Dec 2015
Location: Sacramento, CA
Posts: 107
Total Cats: 15
Default Stock NA8 AFRs w/ LC-1

I'm about ready to install my MSPNP but I'd like to confirm my WBO2 is reading properly. The car is a completely stock 1994 NA8 except at the moment I have the stock O2 sensor swapped for the LC-1 and DID NOT splice the narrowband output back into the OEM ECU. O2 sensor is brand new Bosch 17014 unit, I performed heater/open air calibrations today. Air temps here were ~50deg today. Upon cold-start the AFR reads ~13.5 at idle and slowly creeps up to 14.5-15 when warm. Cruise AFR reads low 15s at 75 mph. If I completely let off the throttle at cruising speed I see an AFR 22.4 until I tip back into the throttle. Seemed normal to me until I started doing some pulls up to ~5000rpm, for which the AFRs stayed between 14.6-15.2. I've read the AFR typically dips to 12-13 region up top, so what gives? I'm thinking the ECU is likely in open-loop which would want to default to a rich combustion scenario.

Tomorrow I will check supply voltage, grounding, and vacuum leaks. Then probably wire in the narrowband output. Right now the ground is @ the 10mm bolt on shelf near firewall/exhaust manifold.
Alumilo is offline  
Old 02-26-2017, 08:14 AM
  #2  
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 2,007
Total Cats: 53
Default

Sounds a bit lean. My 95 was pretty stupid rich above 4K... like 11s if I recall
Stealth97 is offline  
Old 02-26-2017, 03:20 PM
  #3  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Dec 2015
Location: Sacramento, CA
Posts: 107
Total Cats: 15
Default

To correct myself: Cold start-up AFRs start at ~10-10.5 and after about a minute they reach 13 or so. So it seems the gauge is reading correctly.
I'm currently using Analog Out 2 (brown) is input to the gauge, set to default voltage scale of 0V = 7.35AFR, 5V = 22.39AFR. I'll wire Analog Out 1 (yellow) into the stock harness and see if that helps at all.
Alumilo is offline  
Old 02-27-2017, 12:28 PM
  #4  
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Dec 2015
Location: Sacramento, CA
Posts: 107
Total Cats: 15
Default

Yesterday I re-scaled the analog outputs as mentioned above, but didn't drive the car. Today driving to work I let the O2 sensor achieve complete pre-heating before starting the car. During the drive I did several pulls up to ~5500rpm. It seems to be reading correctly. What I was noticing before is this rpm band between 3000-4500rpm in which the AFR remains at ~15.4. The car has always felt sluggish here, and now I know why... Once it gets above 4500rpm the AFR drops to low 13s, and then by the end of the pull its reached somewhere around 12.5. I'm not logging this, just looking at the gauge. The car pulls much better once it gets out of the lean section.
Alumilo is offline  
Old 03-02-2017, 09:41 AM
  #5  
Senior Member
 
Join Date: Oct 2013
Location: NorthWest NJ
Posts: 1,452
Total Cats: 71
Default

Just to verify. The stock O2 sensor is still connected to the ecu?
x_25 is offline  
 


Thread Tools
Search this Thread

Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.