OLFA at 1.0, cold start AFR wandered way lean !
12-05-2005, 04:15 PM
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OLFA at 1.0, cold start AFR wandered way lean ! I had taken yesterday off from working on tuning the car, started in on it again today. When I left off I had it running pretty good after a couple of SD tuning passes, using the HPTuners wideband guide.
In the last thread, I had just set the OLFA table to 1.0 across the board (where before it was considerably richened up in my old tune, richer with lower ECTs).
Today was the first cold start since the OLFA table change. Fortunately I was watching AFR while warming up/idling, it fired up at 12:1 and started wandering leaner and leaner. I got more and more concerned as it kept climbing, finally about 30 sec after startup it got up to 20:1 and I shut the car down.
I went back a couple of tunes and the problem isn't there with the OLFA table back to the old richer values... The cold startup lean problem of course wasn't there when I was SD tuning a couple of days ago with the car being started warm.
Anybody want to take a guess ? It looks like the commanded AFR isn't being reached if it's wandering that lean... Do I need to fiddle with the startup enrichment tables now ?
Should I just go back to my old tune and only set the OLFA tables above 140 or so degrees to 1.0 ?
Gawd, the idle was perfect before I started playing with the tuning, don't tell me I will have to start fiddling with idle AFR settings too now !
Thanks guys,
Rob (Bad30th)
In the last thread, I had just set the OLFA table to 1.0 across the board (where before it was considerably richened up in my old tune, richer with lower ECTs).
Today was the first cold start since the OLFA table change. Fortunately I was watching AFR while warming up/idling, it fired up at 12:1 and started wandering leaner and leaner. I got more and more concerned as it kept climbing, finally about 30 sec after startup it got up to 20:1 and I shut the car down.
I went back a couple of tunes and the problem isn't there with the OLFA table back to the old richer values... The cold startup lean problem of course wasn't there when I was SD tuning a couple of days ago with the car being started warm.
Anybody want to take a guess ? It looks like the commanded AFR isn't being reached if it's wandering that lean... Do I need to fiddle with the startup enrichment tables now ?
Should I just go back to my old tune and only set the OLFA tables above 140 or so degrees to 1.0 ?
Gawd, the idle was perfect before I started playing with the tuning, don't tell me I will have to start fiddling with idle AFR settings too now !
Thanks guys,
Rob (Bad30th)
12-05-2005, 04:33 PM
#3
Read this, it might help: https://ls1tech.com/forums/pcm-diagnostics-tuning/417476-afterstart-enrichment-table-question.html
You don't want to change your OLFA table that much down low
You don't want to change your OLFA table that much down low
12-05-2005, 04:36 PM
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Saw that post...
I'm wondering if it is indeed the air pump. I will try shutting it off and seeing if that's what's making the AFR go lean on the wideband, didn't think of that...
If not I will try leaving the OLFA tables under 140 degrees like they were and see how that works.
Thanks,
Rob (Bad30th)
I'm wondering if it is indeed the air pump. I will try shutting it off and seeing if that's what's making the AFR go lean on the wideband, didn't think of that...
If not I will try leaving the OLFA tables under 140 degrees like they were and see how that works.
Thanks,
Rob (Bad30th)
12-05-2005, 05:57 PM
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Well, doesn't look like it was the air pump causing the lean AFR reading. I disabled it with the VCM controls and the A/F was still way lean and didn't change - and ECT was still about 120 degrees from driving earlier so I'm not sure the AIR pump would have even been on.
I put the old OLFA table back in for 140 degrees and under and that resolved it, according to logging/monitoring... I still have it set to 1.0 for all points above 140 degrees ECT.
I will do some more testing.
Rob (Bad30th)
I put the old OLFA table back in for 140 degrees and under and that resolved it, according to logging/monitoring... I still have it set to 1.0 for all points above 140 degrees ECT.
I will do some more testing.
Rob (Bad30th)
12-06-2005, 01:44 AM
#7
FWIW... I have been working on this problem...waiting for a new wideband sensor to make a full writeup
a quick start is to copy your PE Add vs ECT table across to a row in your OLFA table..and make every row the same way
you can then drive and log ECT and AFR and plot it vs the OLFA table(jst use the ET only..no need for map since we tune with all maps at 1...we wont need to do it by map...just by ECT only)
there are also some tricks you need to do to make sure you can get it right as Afr Error wont work on this...you have to set up a custom AFR error for stioch only and its not really somethingI want to get into right here... but if you stay out of PE you can just eyeball 14.63 if your car is tuned very close to that as an average in your VE
or you can look at the cells that are 1.0 and use those to compare withand make the others match it but you will find out that you need more than just 1.0 up till your full operating temp that you tuned your VE and MAF at..
and your oly 1.0 will be in the ful operating temp.
a quick start is to copy your PE Add vs ECT table across to a row in your OLFA table..and make every row the same way
you can then drive and log ECT and AFR and plot it vs the OLFA table(jst use the ET only..no need for map since we tune with all maps at 1...we wont need to do it by map...just by ECT only)
there are also some tricks you need to do to make sure you can get it right as Afr Error wont work on this...you have to set up a custom AFR error for stioch only and its not really somethingI want to get into right here... but if you stay out of PE you can just eyeball 14.63 if your car is tuned very close to that as an average in your VE
or you can look at the cells that are 1.0 and use those to compare withand make the others match it
but you will find out that you need more than just 1.0 up till your full operating temp that you tuned your VE and MAF at..and your oly 1.0 will be in the ful operating temp.
Last edited by soundengineer; 12-06-2005 at 08:44 AM.
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12-06-2005, 08:25 AM
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Thanks for the good info Scott - I'll keep my eyes peeled for the cold start AFR stuff and maybe work on it more later.
So far so good here with the OLFA tables set rich under 140F.
I'll be doing more VE tuning this afternoon.
Thanks,
Rob (Bad30th)
So far so good here with the OLFA tables set rich under 140F.
I'll be doing more VE tuning this afternoon.
Thanks,
Rob (Bad30th)
12-06-2005, 11:41 AM
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Originally Posted by MeentSS02
Where is the thread where this was discussed before? I need to look back at that...
Thanks,
Rob (Bad30th)
12-07-2005, 12:43 PM
#14
are you still having this problem? was the reading taken at the o2 bung? do you notice a change in the way that the engine is running when it goes lean like this? and the readings before you set the olfa to 1.0 were fine? i need to get a wideband on mine and check it out on start up. i wonder if the idle airflow is off and letting in too much air? kinda worries me now lol ive gotta see what mine is at. yours commands 14.7 when this happens?
12-07-2005, 01:07 PM
#16
Originally Posted by MeentSS02
https://ls1tech.com/forums/showthrea...highlight=OLFA
Found it...are you any closer on your writeup?
Found it...are you any closer on your writeup?
12-07-2005, 01:10 PM
#17
I actually just regained some use of my setup last night...my EIO was getting hot to the touch, and I couldn't trust any of the readings, but I guess last night it was cool enough to keep the temps under control. It has been a very strange problem for me...it gets to the point where the EIO won't even communicate until it cools down.
