It's Alive - Delco 173

[Holden202T]

thats looking alot better!

i'd leave the injector rate where it is for the moment, and start doing some logging and get some steady state numbers to dial the VE table in.

it looks to me like its pretty well perfect at idle, maybe slightly rich but thats no big deal, but at low rpm and higher loads its too lean, that will require the VE table being increased in those areas!

what i'd suggest you do, like you said load it on the brake, get it low in the revs and in the 100kpa column for a few seconds, then see how much change is needed, then apply that to the cell, and then smooth the rest of the cell above it till it matches up with something like 4000rpm cell numbers, ie. to give rid of the dip it will create.

once you have that you'll probably find you'll need to smooth across to 60-70-80 etc map areas to bring them up.

i think you'll find using the calc ve histrogram will give you alot of this information anyways, then its just a matter of putting it into the ve table and making sure its smooth with no massive dips or peaks etc.

[stevemc32]

Got a short run on the brakes and had a go at making some adjustments. I guess such a small sample won't really be too accurate but I've had a bit of fun with it and pretty keen to see if it makes any difference.

Is the VE table the place to sort out that initial stumble or should I be looking somewhere else?

[Holden202T]

the initial stumble is more than likely accelerator enrichment (AE) BUTTT! if the VE table is wrong in any area already then you are only covering that up with AE adjustments, so hold the load at a set point, if the wideband is showing different to commanded then you know its not AE effected and then can make the correct changes to the VE table, then if you still have a stumble its time to adjust AE.

and from what I've seen of your logs its still lean after the AE would have finished which leads me to believe its more VE table than AE.

[stevemc32]

Making some slow progress on the VE table without a great deal of data to work with.

The throttle response is much better now with most of the hesitation gone but there's still a little bit of work to do and I haven't smoothed it over from the last changes yet.

I've noticed a consistent lean idle condition during warm up that becomes rich once up to temp so I assume my VE table is too rich however I can't find a table to offset the VE during warmup. Does this exist?

Also the lean spike after throttle opening is only momentary so should I be too worried about this or just put it down to the system catching up?

[Dylan]

I'm not on my PC so i can't get the exact names but the cold start offsets are done with AFR changes. There's settings for different coolant temps to have different effect and think there's also a time out table aswell.

[Holden202T]

theres a few things.

Map A & B: A/F Ratio - Initial Run A/F Ratio Offset vs Coolant Temperature

Map A & B: A/F Ratio - Cold Engine A/F Ratio vs Coolant Temp and MAP

Map A & B: A/F Ratio - Idle A/F Ratio vs Coolant Temperature

between these you should be able to just about sort out all the changes you need, also with the lean spike, maybe try and change the AE stuff and see if that fixes it, if the VE table is right its more than likely thats what it is!

good to hear your making progress on it, hopefully enjoying the tuning experience too

[Jayme]

might have been written elsewhere... but where did you put the Manifold Air temp sensor? it needs to be measuring the temp of the air inside the intake, preferably a runner. if its just in the intake piping near the air filter its not reading the same thing as the tune is calibrated to expect.

[stevemc32]

Thanks guys, really appreciate the ideas and definitely enjoying learning how to tune this thing, so many questions arise but the old threads in the realtime forum are a goldmine of info.

Concerning the lean warm up, rich at running temp idle condition that I mentioned before I don't think the AFR offset are the problem. The logs show the offset to Target AFR being commanded however the issue is the Wideband not matching the targets as temperature changes. I'll hopefully get a warm up log in tomorrow and try to point out where the problem is but I'm guessing now it's just more fine tuning on the VE table rather than a VE temperature offset that I was expecting.

The MAT sensor is installed just after the throttle body in the plenum, not exactly in a runner but pretty close so hopefully this is ok.

1dscn2165.jpg (141.2 KiB) Viewed 4934 times

More to come tomorrow if the weather is ok.

[Jayme]

that position will be ok ...
during cold start and warmup, I wouldnt expect the wideband to match the commanded anyway. the whole idea of running it so rich is that the engine is so cold that it doesnt burn properly (and appears as a lean condition) I usually just get the operating temp wideband readings to match up and if the cold start is drivable ignore wideband and leave it as is.

[Holden202T]

that position is similar to mine, but mine is in the rear where you bunged it up, I think there is a bit too much airflow here and not enough heat soak from the motor to be calibrated like the v6/v8's are but theres not too many options on a 202.

I had thought of trying the rear end of the manifold where the vaccum module normally screws in, but that's about as far as I got!