ECMlink DSMlink logged AFR's lean

[cdsm25]

Alright, about a month ago I started noticing my afr's going up on my narrow o2(leaner). I have to use the car for a dd right now so it took me a while to get some time to get a log. I started a log at cruise and did a couple WOT pulls. My afr's at cruise were 17-22 and WOT were 13-15. So I try ed to tune richer with no luck. My global was set at 41.8 with 750cc at base fuel of 40psi. I noticed a few thing when looking at the plugs, NGK 6's. They were on the lights side of tan or the darkest side of white. I put some NGK 7's in and cruised the they looked perfect tan yet link was logging the same afr's. Fuel trims were high, -10 to -15 for some reason and my maft-t green light was dim at idle. So I cleared global to 0 same with dead times and with 750 it still ran?? When I first bought the link and did that it was so rich at the 450 setting it would not run. So I put it my global and dead times back and turned on the a/c because I was getting MAD and HOT!! I noticed my fuel trims drop to like -7 to -5, Then I turn on the headlights and my afr's were at 14-16 at idle and fuel trims were good -2 to 2 . WTF, any advice would be great.

 

[gofer]

The advantage you have owning ECMLink is that you can post a log and it will say more than all that ^^^ info you just posted.

Basically, what I'm trying to say is post a log when you can. Your title is mispelled and a bit misleading since its not a ECMLink issue you're having, its more of a fuel trim/o2 sensor issue.

 

[cdsm25]

Yea give me a few. I forgot to mention I have no boost leaks on intake, but I do have some cracks on the exhaust mani and have had some cel's foe malfunctioning O2

 

[gofer]

Yea give me a few. I forgot to mention I have no boost leaks on intake, but I do have some cracks on the exhaust mani and have had some cel's foe malfunctioning O2

Then this post didn't even have to happen then, you already know whats causing the problem. Replace the exhaust manifold and see if it fixes the o2 DTC's, if not replace your front o2 sensor also.

Still post a log, I'd like to see if theres anything else going on as well.

 

[cdsm25]

Log 1 is a crusie with a 2ed gear pull and log 2 is 15 sec with no ac and headlights, then with ac and headlights

 

[bertrenolds]

You could run MAFComp on your log and see what that gives you for suggestions.

 

[cdsm25]

Yea it gave me a templete, yet it put my airflowperrev up to 34-36.

 

[gofer]

AirflowPerRev is tuned to 0.25 @ idle only, you should watch this demo to get an idea of tuning your idle fuel trims. ECMLink Demo: Fuel Trims You don't have the option to run the MAFComp wizard either, you've got DSMLink V2 which didn't have that feature. You'll have to follow the Jeff GST MAF Cal page for your version of DSMLink.

Of course following that video won't do anything until you fix your exhaust leak and failing front o2 sensor, which is evident in the logs you attached above.

 

[cdsm25]

Thanks for the help, I have watch the demo on ecmlinks page on basic setup(many times before), but as exhaust mani fails more and more it will not hold a tune, so i have ordered a manifold and will get an o2 if the mani not the problem. I was getting very frustrated with and started thinking maybe link was the problem. Once again thanks Gofer for your insight,

 

[twdorris]

AirflowPerRev is tuned to 0.25 @ idle only

And even then, you shouldn't get too hung up on it. A 2.4l with cams will routinely run 0.3 or more at idle. Even a 2.0l can vary a bit. It's a general guideline to shoot for 0.24-0.28 at idle, but that's mainly a number you can use just for making sure you're not way out in left field somewhere adjusting deadtime like crazy when you should actually be adjusting airflow.

You don't have the option to run the MAFComp wizard either, you've got DSMLink V2 which didn't have that feature.

He's using the V3 application to datalog (as evidenced by the .elg files posted above), so he has access to the MAFComp wizard. The adjustment points will be limited to V2 MAFComp points, but the wizard still works fine. The wizard is just using CombinedFT and MAFRaw to drive the adjustments (both of which are present in V2 ECUs).

Your "log2.elg" file posted above shows an interesting event around 15.825 seconds. Your O2 sensor went lean there, but I don't believe it's any problem with the sensor itself. I believe something happened there that changed battery voltage or engine load or airflow metering in some way. I suspect your fans kicked on, which dropped battery voltage, which changed deadtime and the ECU took a few seconds to learn this. But without battery voltage in your logs, it's hard to tell for sure.

This page explains what I think is happening in log2.elg:

injbatadj [ECMTuning - wiki]

It's entirely normal and can be fixed with adjustments to the injbatadj table (V3 only). Or you can just let the ECU relearn as it's doing now. You had -12.1% FT before that point and -5.2% after. That's a 7.8% swing, which fuel trims can easily accommodate.

(1 - 0.052) / (1 - 0.121) = 1.078

It would be better to adjust the injbatadj table, of course, because then the adjustment to fuel trims would be instant and your engine wouldn't bog down slightly like it's doing now. But, really, nothing's "wrong" here. It just needs some tweaking.

Thomas Dorris
ECMTuning, Inc.

 

[cdsm25]

Thank you Thomas for seeing these thing. Over the the last year that I have been tuning I have noticed when thing do not go my way its very hard to stay focused on what needs tweaking. I try to read everything and not post to much but your insight helps. hopefully some time soon i can justify buying v3.

 

[gofer]

He's using the V3 application to datalog (as evidenced by the .elg files posted above), so he has access to the MAFComp wizard. The adjustment points will be limited to V2 MAFComp points, but the wizard still works fine. The wizard is just using CombinedFT and MAFRaw to drive the adjustments (both of which are present in V2 ECUs).

Good to know Tom, I thought that was one feature that only v3 users had.

 

[cdsm25]

One more thing sorry for all my punctual errors, I'm really not a Neanderthal. Well maybe sometimes.