Should these flat spots in my narrowband concern me?

[EfiniX]

I've been getting a bit of a misfire lately right around 4200 rpm's with near-WOT. Not all the time, but certainly noticed once or twice over the last few days. I'll be checking my plugs this afternoon and replacing my 9 year old NGK wires. I also noticed in ECMLink that my narrowband O2 sensor is flattening out at idle pretty frequently. Not sure if this is an issue or not, as it does still cycle more often then not, but if it's supposed to be cycling constantly at idle... Well I guess I just don't know.

here's some screen caps from link.

21 seconds of idle


19 seconds of idle


26 seconds of idle

 

[prove_it]

Is the ecm staying in closed loop the whole time?

 

[ghostinthevr4]

He can display if it's in closed loop or not by logging that value particular value 1 would indicate its in closed loop and 0 would mean its in open loop.

I see a few things wrong with that screen shot, the ISCposition is too high it should be hovering around 30, next your your throttle is at 15% indicating your throttle is not closed all the way. Your airflow per rev should be between .25-28 if it's a 2.0L.

Is it possible you have a boost leak have you done a TPS adjustment? I haven't tuned a MAF in ages post a log on ECMLink, someone should be able to give you some help.

 

[GSTwithPSI]

^ I'm assuming only the last screenshot is actually at idle, as the other 2 screenshots show the idle switch at a 0 value. Meaning, the car doesn't know it should actually be idling. It looks like the car is actually getting some throttle input to me /ubbthreads/images/graemlins/dunno.gif

EfiniX, if you want us to look at logs, you should include more parameters. Fuel trims and closed/open loop for starters would be good. Also, being able to see a full log rather than screenshots would be ideal.

 

[EfiniX]

Here's a good one. Actually shows another issue I'm trying to square away.

click

You can catch the idle between 45 and 105 seconds (between some rough driving trying to isolate my misfire). Looks like it's in closed loop the whole time (as this screenshot shows.

This is a 60 second snippet for perspective.




And if you do happen to look at the whole log, you'll see where I think I've tracked my misfire to. I'm running about 10.3:1 AFR at around 3400 RPM's at high throttle position, but I've got a big turbo, so I don't see real boost until around 4000 RPM's. Seems crazy rich to me. My misfire is around 3800-4000 RPM's at high throttle position and I'm guessing I'm getting some spark blow out or I'm just too damned rich. No misfire once I'm through that RPM range.

This bit is somewhat academic as I'm going to talk to English Racing tomorrow both about this tune and getting speed density.

 

[ghostinthevr4]

Quoting GSTwithPSI:
^ I'm assuming only the last screenshot is actually at idle, as the other 2 screenshots show the idle switch at a 0 value. Meaning, the car doesn't know it should actually be idling. It looks like the car is actually getting some throttle input to me /ubbthreads/images/graemlins/dunno.gif

EfiniX, if you want us to look at logs, you should include more parameters. Fuel trims and closed/open loop for starters would be good. Also, being able to see a full log rather than screenshots would be ideal.



Your right the last screen shot is the idle the rpm on that shot threw me off. You have your narrow band 02 simulation enabled and you have a engine coolant temperature malfunction DTC.

Sorry I couldn't be more helpful English racing should be able to square you away tomorrow maybe it's a maf comp issue I'm sure he'll figure it out for you.

As I look through the log more I notice the widbandfactor is way off on some parts your definitely have mismatched air flow readings that's a factor for your misfires when you go WOT. You also set your knock sensor to 5 count's before it even comes on I would set it to 1 but to each their own.

When I go into your display value's you don't have anything to log an actual boost source you have know way of calibrating your airflow.

(actual boost+14.7)/(boost estimate+14.7)-1.0

The number you get is the number you would adjust the airflow. You not logging a pressure sensor to get this number,it's definitely a maf comp issue

 

[EfiniX]

Good catch on the coolant CEL. That's actually an artifact from when I physically pulled the sensor wires off while running to reseat the cables. I was seeing weird output and that part of the harness is a bit goofed. I'm fixing it tomorrow, but I should clear the CEL.

Your input is right in line with what I was expecting. When English first tuned my car in the summer, it wasn't Lucas doing the tuning. If it was, then maybe it wouldn't have been tuned with an EVO timing map. I had issues almost immediately and Lucas noticed and sent me new map. We did a bit of tuning via email and logs and such, but it still hasn't been back up on the dyno. I'm hoping I can get it up there and properly tuned in short-order. Admittedly that was over the summer, but I just never had the time to drive back up there until now.

I'm going to turn the O2 simulation off because hell, I've got an O2 sensor. I'll leave the rest to them. I imagine that switching to speed density will get me that all important boost source.

 

[ghostinthevr4]

You could install a AEM or OMNI bar map sensor to start calibrating your airflow if you want to stay with your current MAF setup. If you go SD you'll you'll have to run a MAP and a IAT for the car to even run some people swear by the MAF's, for me SD tuning is way easier compared to a MAF it's more time consuming but I think the gains are worth it.

Granted I use to tune MAF's when I had DSMlink version 2.5 so that's why I don't like MAF's. Some people don't understand the difference between DSMlink Ver 2.5 to ECMLink we have now, ECMLINK V3 is a blessing for a street tuner.

Tuning on a MAF with V3 isn't as bad anymore compared to 2.5 so don't feel you have to change unless you want too.

 

[EfiniX]

SD going in on Tuesday, so I suppose it's all academic, but I should mention this.

Turned off narrowband simulation and the car seems much happier then before. Logs look right and power comes on smoother. Still running crazy-rich between 3000-4000 RPM's, but I'm guessing this is an artifact of not getting a proper dyno tune, then using a generic 2g tune with tweaks afterwards. it strikes me that a stock 16g would be much happier with the AFR's I'm seeing at 3200+ RPM's. Of course, a T3 T04 w/ a .60AR doesn't need that much gas until north of 4000 RPM's....