I've been teaching myself how to tune over the last couple of months with very little problems and the car feels great up top at 11-12psi with 50/50 water meth. but for whatever reason when i'm cruising around 35-40mph 12.5afr and i stay at that same throttle pos just say 15% the afrs start leaning out to 18.0+ very quickly. Then i have to push in the clutch and let the rpms fall to idle and give it gas/slip the clutch otherwise if i were to slowly tip into throttle there would be no power it feels like its still decelerating while on throttle and sometimes backfires so loud it rings my ears. I've tried changing the accel and decel triggers and sensitivity but it hasn't done anyting. Also If i add or take away fuel in the cell that this happens in and the cells around it also doesn't change anything. Any suggestions?

 

You can email me your calibration file and a datalog showing the issue occurring. I suppose the most helpful template / page to log from would be the Tuning one. Just make sure it has Engine Speed, Engine Load, Throttle, O2 #1 or #2 depending on which you're using, Ign Timing, and Fuel Inj #01 Pulse.

Nathan
nathanmmoore84@gmail.com

 

Thanks for your reply. I'm not sure if it matters or not but my innovate wideband doesn't have analog output ground, so when I connect the output to O2 #1 or O2 #2 it stays around 3.0AFR even with gain adjusted, I unchecked O2 FB control and tuned the fuel map according to my gauge. Is there anything that still depends on the O2 sensor readings that would need to be changed? I'll go for a drive later today hopefully and do a log, just to try to help i will also log the accel and decel parameters.

 

Which wideband?

Obviously running in open loop all the time is possible, but O2 feedback won't ever correct the AFR during day-to-day startup, idle, or cruising conditions for changes in weather. It may be in your best interest to get a wideband that can output to the EMS in the future.

 

I'm using the innovate MTX-OL wideband. I'm considering getting the recommended aem wideband, i just feel like that will just open a new can of worms for me tuning wise. I haven't been able to drive the car for a few days but i plan to today when it stops raining finally.

 

The user manual for the MTX-OL says the yellow wire is the analog output. There shouldn't be an issue with that gauge / controller outputting the data to the EMS, but I've never used anything other than the AEM UEGO personally. I read what you said earlier about the AFR reading 3.0 after adjusting the gain. Did you adjust the O2 Sensor Cal Table in the EMS? Setup > Sensors > Oxygen Sensor > O2 Sensor #1 or #2 > 02 Sensor Cal table > Table

According to the MTX-OL user manual: 0v = 7.35 AFR and 5v = 22.39 AFR

Enter those two values, select the entire table, and use the 'calculate' function to auto-fill all of the in-between values.

You've already done the hard parts of tuning the fuel map without any o2 feedback assistance or AFR logging. Turning on o2 feedback will make user definable adjustments (typically +/- 10%) to the AFR during low load scenarios like idle, cruise, and light acceleration. Just have o2 feedback turn off once the engine sees 5-10psi of boost, and you won't have to worry about anything weird happening when you go wide open.

 

i went for a couple drives yesterday and did a log and before i even left my driveway i noticed my TPS value was different than i last set it at. i started wiggling the wires to the TPS and the percentage was jumping everywhere... i redid the wiring and the percentage is stable now. The problem is still there but isn't nearly as bad, it seems to be alot more driveable now i think it might be all down to the fuel map at this point, also before writing this i tried fixing the 02 sensor i'm not sure if its actually reading but i have my yellow wire to 02 #1 its reading 3.29AFR on parameters and i can change the minimum value to 7.35 but i cannot change the max value higher than 9.59AFR on the Sensor Cal table

 

Well, it's good that you found an issue with the TPS. More often than not, weird issues like this end up being a bad sensor or wiring.

If you want to keep troubleshooting the O2 sensor problem, email me your calibration and I can take a look at it. It's your call.