Tuning questions & Interesting Observations

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May 23, 2001 | 07:40 PM
  #1  
I've been tuning for three or four months now.
I've programed 72 chips and got my tuning allmost perfect.
Timing tables, fuel tables,open loop tables, & the MAT tables from 10degC to 40degC.
I've been working on the PE tables and got them close but I noticed somthing odd today.
I made five WOT runs, each run I pulled 10psi at 5200 rpm.
on some runs my o2 was in the 850's and others the o2 was in the 800's.
After reveiwing the Data I notice that the FT cell was at 4 on some runs & 15 on others whats up with that.
Anybody have some thoughts on this.

------------------
Louis
Convertable
92 Z28 305tpi Auto
1/4 at 13.23 @ 106.1mph w/Paxton 10psi, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9 camaro SS wheels, 285x40x17 tires,and much more.
http://www.lbsz28blown.cz28.com
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May 23, 2001 | 10:22 PM
  #2  
Quote:
<font face="Verdana, Arial" size="2">Originally posted by LBSZ28BLOWN:
I've been tuning for three or four months now.
I've programed 72 chips and got my tuning allmost perfect.
Timing tables, fuel tables,open loop tables, & the MAT tables from 10degC to 40degC.
I've been working on the PE tables and got them close but I noticed somthing odd today.
I made five WOT runs, each run I pulled 10psi at 5200 rpm.
on some runs my o2 was in the 850's and others the o2 was in the 800's.
After reveiwing the Data I notice that the FT cell was at 4 on some runs & 15 on others whats up with that.
Anybody have some thoughts on this.
</font>
Tuning by O2 voltage will bite you.
They are switching devices.

72 and perfect?.
Well, hang out a while and you'll see it takes alot more then that to get close to perfect. Bettter then stock I'll grant you but perfect takes lots of time and tinkering to find

Read the Plugs to see where you at, Mixture and Timing wise.

I fins it hard to beleive you got WOT right in 5 passes.

hate to be negative, just I think you missing alot.


Reply 0
May 24, 2001 | 07:43 AM
  #3  
Grumpy,
I ment I was getting close on the PE tables,
I,ve been working those PE tables on the last 10 to 15 chips.
I brought up the last 5 WOT runs because of the changes I'm seeing in the tune.
Those last 5 runs were about 2 minits apart with no changes to the car or chip or outside Temp and on the same road.
Not only did I see the diferences in O2 but in FT cell.
each run the same but the runs that where in the 800's O2 the FT cell was 15 And the others the FT cell was at 4 with O2's in the 850's .
Why is the FT cell changing I thought the FT cell should allways be at 4 for WOT.

------------------
Louis
Convertable
92 Z28 305tpi Auto
1/4 at 13.23 @ 106.1mph w/Paxton 10psi, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9 camaro SS wheels, 285x40x17 tires,and much more.
http://www.lbsz28blown.cz28.com
Reply 0
May 24, 2001 | 07:46 AM
  #4  
Have you looked at a graph of the O2 sensor's output? You should. 800 doesn't really mean leaner than 850. Depends heavily on temp.
Reply 0
May 24, 2001 | 08:01 AM
  #5  
I reveiwed all the Data that I recorded on those 5 runs and when I was in the .800's I saw 2 to 4 deg of knock retard and the runs that the O2's where in the .850's I had no or 0 knock retard.
Also the Injectors where in the 11.4's pws on the .800 runs and 12.4's pws on the .850 runs.
the only thing that seems to be changing the tune seems to be the FT cell trim,
I just don't no why the FT cell changes under WOT runs.
Reply 0
May 24, 2001 | 08:42 AM
  #6  
I can't answer your question on the fuel trims. In my quest to tune my 396 89 vette currently with a 165, I have come to find some wierd things also. For example, at open loop cold idle, my commanded AFR switches to 36:1 for a split second and then back. Sometimes my block learn in open loop is 132 when I expect it to be locked at 128. Never did find what was going on so I stopped looking.

If your in cell 4 during WOT, is it all the way up to redline? Are you still entering PE mode? I had a situation where at WOT I was not entering PE mode and the ECM was trying to maintain 14.7. Turns out that once the TPS voltage goes over I think 4.8 volts, it kicks out of PE. I asked dozens of people why and no one knew.

72 chips and almost perfect? Well I guess you learned not to ever say that again huh?

------------------
89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers
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May 24, 2001 | 11:36 AM
  #7  
Yes, it stays in that FT cell all the way to red line, FT cell 4 or FT cell 15 which ever it starts out in.
Also it dose stay in PE mode and my TPS stays at 4.62 volts all the way up in WOT.

Yes , I Should say the tables are getting close and the driveability is much improved.

BTW my BLM's are 128 to 126 at all the Data points I've recorded on my Daily 60 mile trips to work and back.
The INT's run at 124 to 133.
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May 24, 2001 | 11:57 AM
  #8  
Quote:
<font face="Verdana, Arial" size="2">Originally posted by LBSZ28BLOWN:
I reveiwed all the Data that I recorded on those 5 runs and when I was in the .800's I saw 2 to 4 deg of knock retard and the runs that the O2's where in the .850's I had no or 0 knock retard.
Also the Injectors where in the 11.4's pws on the .800 runs and 12.4's pws on the .850 runs.
</font>
11.4 and 12.4 where in the rpm band?

I know most people believe the O2 sensor is a good A/F meter, but listen to Grumpy. It is only good as a rich/lean switch. Someone please post that A/F vs. temp vs. voltage graph.
Reply 0
May 24, 2001 | 12:58 PM
  #9  
Boy that's a wierd one. Sorry I can't help.

Jason

------------------
89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers
Reply 0
May 24, 2001 | 03:36 PM
  #10  
at .800's O2
The injectors where staying at 11.4pws from 3200rpm up during the run in each gear.
At .850's O2
the injectors bounced from 11.8 to 12.4 pws in the same rpm band.
It appears that when the EMC switches the FT to cell 15 at WOT the engine leans a little.
when its at FT cell 4 the engine richens a little.
I'm going to do some plug reads tomarrow if time permits.

------------------
Louis
Convertable
92 Z28 305tpi Auto
1/4 at 13.23 @ 106.1mph w/Paxton 10psi, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9 camaro SS wheels, 285x40x17 tires,and much more.
http://www.lbsz28blown.cz28.com
Reply 0
May 24, 2001 | 05:23 PM
  #11  
Quote:
<font face="Verdana, Arial" size="2">Originally posted by LBSZ28BLOWN:
at .800's O2
The injectors where staying at 11.4pws from 3200rpm up during the run in each gear.
At .850's O2
the injectors bounced from 11.8 to 12.4 pws in the same rpm band.
It appears that when the EMC switches the FT to cell 15 at WOT the engine leans a little.
when its at FT cell 4 the engine richens a little.
I'm going to do some plug reads tomarrow if time permits.
</font>
Not to promise anything, but send me a.gdf of each, and letme see what you got going your PW statements just aren't clear to me.


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May 25, 2001 | 12:26 PM
  #12  
Quote:
<font face="Verdana, Arial" size="2">Originally posted by Grumpy:
Not to promise anything, but send me a.gdf of each, and letme see what you got going your PW statements just aren't clear to me.

</font>
I'm useing Snapon Scanner with scangrafix software to do my Data recording.
I'll check and see how I can send you some readable grafs or data to you.
Thanks
Louis

------------------
Louis
Convertable
92 Z28 305tpi Auto
1/4 at 13.23 @ 106.1mph w/Paxton 10psi, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9 camaro SS wheels, 285x40x17 tires,and much more.
http://www.lbsz28blown.cz28.com
Reply 0
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