Wideband Tuned - Closed Loop Rich?

[BigDaddyCool]

Tuned the MAF & VE via wideband but since putting it back to normal in closed loop etc....... noticed various issues.

So I've switched to just running MAF with LTFT turned off to get an idea of the STFT gear.....

STFT's are around -2 to -3 in the lower maf hz area's, going to -5 etc in the higher 6000-7000hz area on the maf and then dropping down to like -2's ......


My question is this:

What do I need to change in the closed loop to make the O2's bounce quicker to tighten the STFT's up....... I dont want to do it via the MAF because I know it's tuned right from my wideband.......

Would this be eg lowering. Closed Loop Proportional - Airflow Mode? Or is there a better way.

Closed Loop Intergrator Delay? Lower that?.....

Hopefully someone will have some advice for me this time on this thread....

[ingsteve]

you need to reset fuel trims, then drive 100miles as a minimum and verify the LTFT.
This is a long term average and for sure more accurate then log only stft in a short time. Also -5 is not something to continue having headache...

[BigDaddyCool]

Problem i've found is the ltft seems to want to adjust the stft even if it's not that large..... I dont like LTFT's because they can carry over to WOT at random times.....

I'd rather just make the o2's flick back and forward quicker to keep the trims as close to what i have set for the maf as possible.

[ingsteve]

positive LTFT are passed to WOT, not the negative.
If you have LTFT between +-5% you can disable LTFT and tune with STFT only bu again i would have the LTFT checked after 100miles.

[5_Liter_Eater]

Leave LTFT disabled indefinitely and don't worry about +-5% STFTs. -2 to -5 is already pretty tight.

[BigDaddyCool]

Alright I thought I'd post a log.....

I reverted back to the stock VE, made some adjustments to MAF, PE etc..... Turned back on LTFT's etc.....

It seems to be fairly good now. I still get the RAMJet leaning out off throttle but within like 10+ when it does do it, better then the 31+ I had originally before I wideband tuned the MAF and adjusted various things.

No knocking which is good. Unforunately I'm thinking I really need to take it to a dyno shop to have them dial in the MAF at the higher airflows on the dyno at this stage before you cant really do it on the street etc.

Still power seems good now.... trims are in order, driveability and response is good. I have V4 mode on..... and have PE controlled by the throttle mostly.....

I've found just richening up the maf 6000-7000 helps the power while at non-pe...... some people throw TPS to 5%, MAP to like 65-80 etc to get it to throw the fuel quicker but it doesn't really work if you want V4 mode....

So you really have to control PE via the TPS.

Anyway have a look at the log, I'm not posting my tune because it's mostly finished but you get the idea....

I dont really just adjust the MAF via histogram averages etc, I do it via what's recorded as the min or max for final adjustments and only if i feel there's no power there or an issue etc.

But I'm happy, got rid of all the knocking I had with VE and LTFT's on.... I think that EQ VE program is a pile of rubbish myself..... After checking some things it does, it doesn't calculate properly, it can be like 3% out on the equations etc.

When I find time I'll revisit VE when some better stuff comes available.... EFI is probably better for VE stuff....... but it doesn't ultimately matter, I assume most cars are like mine and take a VE figure and adjust it up according to the maf stuff reported.

My problem was that I had my own tuned VE gear in there which obviously didn't work properly after I put the car back to normal.... who knows.

I've managed to sort out power so it gets a nice build from off the line to max RPM, I found timing and fuel ratio's have to be smooth and build so you can get the air into the cylinders stably increasing to keep power climbing.

According to the scanner I'm putting out a max 555-560nm @ 4400RPM, not sure what that translates to the wheels but the torque is a nice steady climb now from the rev range.

I scraped all the 'custom PE' crap for the top end and set it back to stock and just adjusted 3750rpm lower....... left the top fully stock fueled up, I find it keeps the power at it's maximum in any weather, cutting it down to even 1.17 starts to lower power on a hot day.

Main issue I have now is take off....... I get some wheel spin from stand still random plant..... takes about 2 seconds .... I might reign this in with the TPS rate limits, but I find that annoys me to, another option is to remove some timing and lower fueling but I dont really wanna do that either

Adjusting the Cyclinder Charge Temp helps with the response bigtime.... annoying to get right tho ....

Thats my blog for today.... Any pointers on the scan, anything you think I might be able to regin in with the fuel dips rich or lean would be great...

[LSxpwrdZ]

Do you have EVAP on this car? You have to be patient with fuel trims once you go from open loop to closed loop as EVAP does not function in open loop and the fuel vapor builds up in the tank. When injected it will show richer than desired for a little while.

If that is not your case then you probably need to verify your wideband readings while in closed loop to see where the discrepancy is.

[Jamz]

Sorry to hijack. It i am too Interested in how to get the 02s switching faster with lt headers.

Also which table to you adjust the tps rate?

[BigDaddyCool]

I actually took the stock Holden Commodore VE SS Series II o2 switching table along with the Proportional gear, works really well.

TPS is under airlflow, etc