Gas Lift Off- NO DFCO AFR 18+ - Injector Short Pulse?

[BigDaddyCool]

Mafless. VE is as correct as it will get, adjusting the off throttle area's only results in really rich conditions.......

But I dont have DFCO, CFCO, NoFastTorqueExit,NoTipIn.

Everytime I lift off the gas, it shoots flat lean. It's been an ongoing issue thats gotten worse and worse with mods.

My question surrounds the short pulse adder, has anyone adjusted the min pulse width to ensure the car will get fuel under such conditions?....

[SultanHassanMasTuning]

if your off the throttle coasting, initially it will go flat lean then to stoich

[BigDaddyCool]

And when it fails to return?

[SultanHassanMasTuning]

^your applying on the gas again after coasting and fueling is still lean?

[BigDaddyCool]

Rather then going on, attached file.

Basically if I let it coast it stays lean in alot of spots........... if I stay off throttle it stays lean...... I just noticed looking at the log the fuel trims also disappear..... But I have no DFCO on of CFCO. This is custom os, I'm still wondering if it has bugs in it.....

If I get back on throttle problem is..... it is lean then on tip in and can cause knocking etc, plus it heats the cats up and the engine...... I want to get it away from all this.

Since I had hi-flow cats fitted my fueling is crazy now........ it's like a wave constantly, can spike 25% lean down to -30% rich and working on VE or if I refit MAF even with the stock throttle settings etc doesn't change it. I haven't yet inspected my wideband or the stock o2 for leaks since they did it but it seems strange to me.

It's driving me nuts, now also it shoots lean on full throttle in most spots........ I have tried to run stock tps delays, massively drop when the TPS engages PE or even set PE at 2.0 and it will still shoot lean. It makes it hard to try and fix fueling when one minute it's like 15% lean and within a split second 9% rich etc. Running it richer bring on knocking etc.......

Anyway, I think focusing my efforts towards this weird trim issue off throttle will probably help things overall by keeping the cyclinder temps down. It's either that or because of all my mods I now need to change the charge temp tables.

I have already added a heap to transient as it's mafless, setting that to stock is not the answer......... so perhaps it is in the charge temps I need to look at.

[02statesman]

or if I refit MAF even with the stock throttle settings etc doesn't change it.

Did you run it as MAF only or as MAF/SD?

[BigDaddyCool]

That particular log is mafless, I can run maf only and the result is similar

[02statesman]

Maybe your exhaust people wired your o2 sensors back in on the wrong sides (left on right and right on left) after fitting your new cats.

[BigDaddyCool]

The cars in open loop so they shouldn't effect it.

Drivers side has wideband in header, o2 before cat. Passenger is o2 in header..... So I'm going to move my drivers side o2 into the header where it normally sits and move the wideband behind it just before the cat........ And see if closed loop can help with the as i call them arctic sea of waves.....

I've never really seen anything like it........... transients make it hard without a dyno to sit in steady state on.....

I feel like my transients kick in too late or my widebands lag has increased......... or both. ATM Im on my stock timing and TPS response etc until I can get a handle on whats going on.

I had a look through the injector pulse scenario, wasn't my issue...... Doesnt even come close to min width.

It for start is VE and combustion temps in the cylinders..... I've begun the progress towards richening up on a nice big flat scale on the VE table.... to see how it progresses overall...

The professional tune I had done pulled like a massive amount of timing........ and leaned fuel out.......... why...... it didnt add power it stripped the car of all power...... And since Ive begun the process of working on correcting the VE fueling......... the knocking of the stock table is mostly disappearing as the fuel gets closer to spot on.

Anyway to end this thread......... in my case increasing the min pulse didnt help.....

I even flashed up a full HSV tune up onto the car with keeping my VE table to see if it would change anything, it did run a little off ....... more rich then anything off throttle but overall no difference and the HSV is quite different to mine......

I think the overall point and answer to this thread is this.......

I need to work on VE on a small but widely spread scale, VE has to be real smooth outside where you want immense power specifically. What i find frustrating is now with all my mods I can clearly see how the stock cam is just CRAP....... doesnt make power until 3800rpm then shoots to 4600rpm flatens to like 5200rpm and then falls off......

No power before 3800rpm really, and none as it begins its downward decent especially past 5600rpm.

Cars are a money pit, cam, then diff, then stall....... anyway......... Injector pulse theory proven wrong, go back to fueling VE or MAF... whatever or however your doing it.