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View Full Version : B3618 using LTFTBEN for update to fueling


stigmundfreud
July 6th, 2010, 07:30 AM
Whilst waiting for the wideband to turn up my friends tune is dangerously lean. I've increased the main VE table by 20% to get things in general a lot closer (all LTFT and STFT were between 20 to 30% on average so did a broad uplift to get a safer base).

Using LTFTBen I can control conditions outside of PE mode <80 kPa but as the car is FI I am worried about setting PE to EQ1. Currently Openloop VE is set to EQ1 and PE set to 1.13 (with some richer cells but thats average)

Now is it possible to use LTFTBen in these areas to ensure commanded is close to what we aer getting or will they be disabled as STFT's are off in PE mode?

I dont want to run a lean car even leaner in PE mode. The alternative being to increase the PE VE ranges a further 15% then wait for the wideband to turn up and finish off PE with that and on a dyno too.

Is there simply a way to get LTFT to account for commanded AFR to say thats the value it should be trimming to? Ie commanding 14.6 = 0 LTFT when dialed in but in PE range LTFT of 0 = commanded PE figure?
mr.prick
July 6th, 2010, 09:12 AM
Why would you set PE to 1.00??

The AutoVE Tutorial has it backwards,
you set the Open Loop Fuel Table to 1.00 and leave PE on.

But please wait for the WBO2 before doing anything.
joecar
July 6th, 2010, 09:14 AM
The trims don't work when commanded AFR is away from EQ1... in PE mode, the previous positive LTFT is added to fueling as a safety measure.

Your best bet is to add 15% to VE PE region and to increase PE to say 1.17+ (since 1.13 seems a little lean for FI)... may be safer to avoid WOT until the wideband is installed.
stigmundfreud
July 6th, 2010, 01:21 PM
Why would you set PE to 1.00??

The AutoVE Tutorial has it backwards,
you set the Open Loop Fuel Table to 1.00 and leave PE on.

But please wait for the WBO2 before doing anything.

I wouldnt but the tutorials would have you. Nothing is going to be done until the widebands are here but for now have increased the ve tables to get more fuel in there.

have also suggested he does not drive car until he can get even basic logging available