part throttle VE tuning with WBo2

[PJG1173]

I have a question about ve tuning with a WB. when I put hedders on my engine I had to relocate the NBo2 which caused the readings to either be slow or way off. I thought since it was a heated sensor this wouldn't be an issue, but it made tuning using BLM's a nightmare. Since then I added a WBo2 connected to my autoprom. I'm still chaseing my VE tables around. The issue I think I am haveing is AE and decel skewing the numbers tunerpro is collecting in a histogram. As I understand it if I was using blm's, learns would be disabled while AE and decel were active. Is there a way to filter this data out? how do other people tune part throttle via WB?

[EagleMark]

Man this is going to be a good thread!

But would have to know what ECM/PCM/Mask your using?

Where is your narrow band O2 sensor mounted now? Where is your Wide Band O2 sensor mounted? This can play into getting good info from WB and NB telling ECM wrong stuff...

Even if ECM/PCM has not met qualifiers for BLM learn it still spits out BLM numbers in historygram in TunerPro. Decel Fuel Cutoff (DFCO) is usually MAP kpa lower than idle kpa and I've never adjusted them, just smooth a transition from driving range. AE does not mess up BLM in $42, if you disable it the motor runs like crap and does mess up BLM so I leave it, may add to it later, but I do disable PE when trying to get VE tables close, you can get more BLM tables filled in without PE skewing the number. You probably know everything is based off VE tables so getting them right first is key. Depending on ECM/PCM you can disable DFCO usually by TPS% or temp or?

HTH get you going!

[1project2many]

Hah! Mark replied while I was typing. I guess I talk too much. :)

Adding headers should increase response times in the range of milliseconds. I've added headers and changed exhaust configuration on several vehicles without altering the values for O2 response time and still successfully tuned the engine. If you're seeing it take longer to reach a correction point the reason isn't because the O2 sensor takes longer to respond to the oxygen content in the exhaust, the reason is because there's been a change in the amount of unreacted O2. One possibility is that the combustion reaction, which often continues in the exhaust manifold, has been slowed or stopped by the headers cooling the exhaust. Another reason could be the headers have dramatically changed the fuel requirement. If the problem is truly due to slow response to exhaust pulse I'd love to see it happening.

AE and DE are very rapid and generally occur faster than the ECM can respond through INT and BLM. These modes are directed by fast change in TPS or MAP and are designed to cover the transition caused by this rapid change. In fact, they exist because the ecm cannot respond to them quickly enough through the O2 feedback loop or the VE table programming. Power Enrichment is long term and will generally force open loop. DFCO should in theory force open loop but I've seen a couple of GM cals which do not follow this thinking.

What I've done for tuning when the BLM and INT are making wild swings during load / unload conditions is to force min and max BLM and INT to 128 and use the O2 reading directly for my tuning. The engine will run badly if the VE is way off so you won't be able to skip adjusting the cells which require adjustment. VE and timing need to be addressed first so find a hill or a way to apply a load under steady state throttle then make corrections one cell at a time using data recorded on the scantool / laptop. If you suspect AE and VE are causing problems, zero them out or disable them. You'll stumble, spit, and cough when moving the throttle quickly but if the VE is correct, as you slowly move the throttle to a specific position or load value the engine will operate correctly and O2 should hover near .450 volts (I actually shoot for .48 - .50 V) during steady load operation. From this point tuning AE and VE is really a task of maintaining O2 voltage near .450 as the throttle is opened or closed. Remember that steady state VE is the main MAP and that AE and VE are in place to make up for air density changes which the ecm can't handle through the feedback loop.

HTH

[PJG1173]

Wow I wish I could have got this fast of a response on the other forums I posted on. I am running 16168625 $E6 mask. I have dfco disabled and I set the TPS % to 98% for PE. I have left AE alone so far. one of my big issues is this is my first time tuning and I changed almost everything on this engine. litteraly the only thing original is the crank, rods, and injectors. so yes the fuel and timing requirements have drastically changed from stock. Like an idiot I dove into this project as my first tuning experiance. I have hardly any logs from when it was stock.

The NB is mounted in the collector on the passenger side hedder and the WB is on the drivers side. thats about 8 - 10 inches further down the exhaust tract than stock. I am currently in OL and it runs decent. I have been solely tuning off the WB readings not the NB. since I am in OL there are no BLM's to compare to the WB. I have the WB simulating NB to the ecu but once I enable closed loop things start going down the crapper. I have been meaning to hook the NB back up to see what it reads now gas isn't pouring out the tail pipes anymore. my ve table looks like a mountain range. I idle at 45kpa and at cruise I'm around 80ish kpa. I tuned idle using the same theory I use for a carb. i increased or decreased fuel until i hit the highest vacuum reading. the WB reads 13:1 @ 650 RPM and it idles nice and smooth. to me that seems rich for idle, but the exhaust does not smell rich. How do I compensate for the hedders/NB location or should I even have to? could it be something else like too little of AE that is messing with my numbers/ve table?

May be (more like probably) I'm doing something wrong here.
included is a graph of my ve table from an old tuning session and the log it generated. I haven't worked on the truck in a couple weeks so I don't have anything more recent with me. I also attached a copy of my current bin if anyone wants to look at it.


Here's a quick breakdown of the mods.
93 chevy s10 ex cab
01 4.3 block bored .030 over
2 valve relief flat top graphite coated hyperT pistons
9.8:1 compression
edelbrock 2114 intake
stock injectors @ 15psi
adjustable FP regulator
TBI with ultimate tbi mods
TBI spacer
ported and polished vortec heads
back cut valves
comp cams 266hr
arp rocker studs
1.52 roller tip rockers
hedman long tube headers
cold air intake
built 4l60e
2075 stall converter
moates.net autoprom
Crane HI6 CDI ignition
4.88 gears
35x14.5x15 TSL boggers

[gregs78cam]

First off I would tell you to hook up the real NBO2, and disconnect the simulated one. I traced a few of my issues to the simulated NBO2 output. Then get some logs recorded in Closed loop.

[EagleMark]

Wide Band O2 simulators are not all they are cracked up to be... like Greg said, but your saying your open loop? So maybe you are open loop with WB/NB simulator?

But your doing good for a first tune on a built motor!

If you are open loop and you ever want to run an O2 sensor I would get your WB AFR closer to 14.7 to 1 because that's where the Narrow Band O2 sensor is going to want to put them. This will get your VE table close. Then run closed loop off O2 sensor and finish VE with BLMs.

You may get a better vacuum at idle by bumping it up to 700-750. Or even run open loop idle. When you get idle up do a Minimum Air Adjustment on throttle blades and get IAC count to around 10 -20 at idle. More air over throttle blades pushing fuel in. Just give IAC a little control of idle.

Then use your Wide Band for WOT runs and get the AFR down to 12.5 - 12.8 to 1 AFR. Unless it's just for race then tune it all that way. Look in the ECM Information thread for a PE Delay zip file which explains the barrage of qualifiers needed to be met to enter PE including up to a 70 second delay?

[PJG1173]

I'll hook the NB back up and set the bin back so I will go into closed loop and see what happens. that was the idea all along just without using the NB. I just have been having a heck of a time getting the afr close to 14.7 the best I can get is 14.0 - 15.7. all I have to do is find time...