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Cant get o2 to cycle

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seattleshawn

10+ Year Contributor
148
2
Feb 7, 2010
Edmonds, Washington
Take a look at this log and tell me what I'm doing wrong please. It will go into closed loop but wont cycle. Timing is dead on and there are no boost leaks. I'm new to tuning so be gentle please. thank
 

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Only place i could start is by getting ## airflow table set up and mabye that would cause it to cycle? Follow these threads.

Deadtime affects idle more than anything. That said, your airflowperrev is high and combinedft is low at idle. Try lowering your mafcomp sliders at 0-50hz and see how combinedft and airflowperrev reacts. You could select the first 60sec (idle segment) or so and try mafcompadj tool to get an estimate of where the first few sliders should be...

Using the mafcomp sliders, get airflowperrev in the .25-.30 ballpark and then use deadtime to get combinedft near 0%

All of which is covered in this video:
Fuel Trim
 
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Follow these threads.

Deadtime affects idle more than anything...

I've heard this before :p You mean this thread:
http://www.dsmtuners.com/forums/153111460-post5.html

Except his airflowperrev is high and combinedft is high...he needs to adjust his global fuel

OP, you have your LC1 in the front o2 w/narrowband sim. Yet, you're not logging the LC1...why? Also, the default switch point is 2.49v, yours is set at 2.45.

You should be logging more values:
http://www.dsmtuners.com/forums/ecmlink-tuning-help/444831-list-values-log.html

Capture the LC1 along with other values and post another idle log please...
 
Well to be honest I'm not sure how to log my wideband. I dont see it in the list so i guess I'll need to do some more reading and see if I can figure it out. The reason my switch point is set to 2.45 is because according to the ECM WIKI for an LC1 WB the switch point should be 2.44... Either way i guess its wrong. Which is correct 2.49 or 2.44?

I'll do as you suggest and get another log posted tomorrow.

:hmm: Ok I may have found a giant issue here. I have the flow data sheet for my injectors from FIC. According to them with a base pressure of 39psi at 12 volts the injector voltage offset is 1.20 milliseconds (1 millisecond = 1000 microseconds). I believe offset is the same as deadtime and if that is true than my deadtime should be about 500 not 330. ( ECU assumes 700 microseconds)
Somebody please confirm this cause that could explain some of the issues I'm having.

Just for reference these are the other values are listed as well

39 PSI 14 volts = 1.10 milliseconds
39 PSI 16 volts = 0.75 milliseconds
 
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Well to be honest I'm not sure how to log my wideband. I dont see it in the list so i guess I'll need to do some more reading and see if I can figure it out.
ecmlink101datalogging [ECMTuning - wiki]
OR
http://www.ecmtuning.com/demos/capturedvalues.html

The reason my switch point is set to 2.45 is because according to the ECM WIKI for an LC1 WB the switch point should be 2.44... Either way i guess its wrong. Which is correct 2.49 or 2.44?

Read this:
http://ecmlink.com/wiki/v3narrowbandsim said:
The best way to determine your own switch point is to datalog the wideband kit while running closed loop off a stock narrowband sensor and then simply take an average of the raw wideband voltage (available in the datalog as a Raw value) while the narrowband sensor is cycling normally.

My LC1 switch point happened to be at the default value of 2.49v. I kinda assumed all LC1's operate around this value, but this is not necessarily true. I realize your o2 isn't occilating so, you'll have to wait until it's fixed.

Ok I may have found a giant issue here...

You're combinedft won't be right until you resolve the o2 problem. As long as you have an idea of where global should be about, let's focus on getting the o2 working properly...

I'll do as you suggest and get another log posted tomorrow.

Yeah, get the LC1 logging and let's go from there.
 
Ok 3 more logs. I'm now logging the WB and I increased the deadtimes to be more inline with what FIC is recommending. I made some adjustments to mafcomp based on the second log but then the it started pouring down rain so I had to cut it short. It looks like i need to make some more adjustments based on the 3rd log. The o2 is cycling but it looks kind of strange based on what I have seen on other logs. I also noticed my BOV is venting a small amount of air at idle. I'm thinking this is not normal and it probably needs replaced or is this normal?
 

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The o2 is cycling but it looks kind of strange based on what I have seen on other logs.
It looks okay to me, although I'd bump the switch point to 2.47v (based on log 3)...

Well, I think it's safe to say that your o2 is cycling now...perhaps mark as resolved?
 
It looks okay to me, although I'd bump the switch point to 2.47v (based on log 3)...

Well, I think it's safe to say that your o2 is cycling now...perhaps mark as resolved?

Yes I will do that. Thanks for your help man much appriciated.
 
seattleshawn said:
Thanks for your help man much appriciated.

No problem at all, you're welcome.

I also noticed my BOV is venting a small amount of air at idle.

Hmm, the only advice I can give is to do a boost leak test, consider crushing it (assuming it's a 1g), or get a tial :sneaky:

I'd say your next step is to go through this checklist: http://www.dsmtuners.com/forums/ecm...efore-you-ask-ecmlink-dsmlink-log-advice.html, and then get your idle dialed-in. Don't forget about this:

using this:
 
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