Idle is hammered out, but when I blip the throttle it takes way too long for the RPMs to drop. They are hanging. I was adjusting the throttle follower decel. rates, but i've doubled those values and it's not fixed. What can I log to determine what they need to be? Suggestions?
Originally Posted by 08z06
Ok, here is what I found. The idle issue was a result of the minimum idle airflow table. I adjusted these and things started to settle down.
One issue I just realized was that my Long-Term Fuel trims are up around 24% and they shoot up quickly at idle. I reset LTFT's at idle and watched them shoot up. When I did Speed density tuning and the MAF tuning I had them disabled. Any ideas why they are so out of wack now? How do I get these back into check?
I think it occurs at idle, which was my issue before. At cruzing speed my WBAFR gauge stays around 14.63, which is great. At idle and lower RPM's there isn't enough fuel. Would the MAF and VVE tables not correct the fuel requirements? I am thinking the MAF/Min Idle Airflow Rates have something to do with this. Curious of your thoughts and how I can resolve.
Last edited by 08z06; May 1st, 2015 at 03:56 PM.
Well, I got it figured out. Got my VVE table dialed in to within 0.5% either way of stoich. After that I dialed in the MAF. The MAF tuning fixed my LTFT's. Now they are reading, on average, between 0 through -4.5%. I think I am in business now. Still need to tune the PE on the dyno, but that's for another day. For now I have it commanded to 13.5 or so.
Thanks for the help JoeCar
Good job... (it drives home that large LTFT's are an indication of the prevalent air table (MAF or VE) being out).
Post before and after tune files so I can take a look (and learn something)...
I'll get them posted for learning material.
With my MAF and tuning tables updated I re-enabled all the sensors and maps. My Wideband AFR Gauge is reading VERY close to 14.83 nearly constantly. At idle it doesn't even move. This is as intended correct?
Yes, that is what tuning does.
wanted to make sure that the car WANTED to command to Stoich at all times, except for power enrichment. THat was my understanding but never read it anywhere.
Ah, I see what you're saying (I had latched onto the words "nearly constantly").
What Lambda does SAE.LAMBDA report...?
What Lambda does the wideband report...?
What wideband do you have (what does it assume for stoich AFR)...?
What fuel are you running (what is the alcohol % content)...?
What is the stoich AFR set in your tune...?
Post a log file showing this.
see info above
Why did you set your stoich AFR to 14.83?
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