VE Table Help

[vc81]

Thanks Jayme & holden202t for your answers in the above posts. I'll have a crack at it this weekend.

[vc81]

Had a play with the VE table today just sitting in the driveway free reving the engine. I held the rpm in each of the individual cells around the 30-40kpa area at about 800-1400 rpm and checked if they matched the wideband afr reading. Those cells didn't match the afr table. The afr table was says 14.7 and wideband was reading 13.2. I changed the numbers in these cells to get them as close to 14.7 as I could.

Am I doing this the right way? As the engine seemed to idle rougher after doing this.

Some of the cells higher up in the revs around 3000 rpm matched the wideband reading spot on.

[antus]

Match against the target afr thats in the datastream. If the engine is cold or at least not up to running temp itll be targeting richer than whats in the ve table

[vc81]

How do I read the target afr in the datastream? Why does it target richer than what's in the VE table when warming up?
Thanks,
vc81

[antus]

Its like a choke on a non-efi car (but more accurate) have a read of some of the guides in the faq area (link up the top)

[vc81]

Ahh ok. I had a read of the basic guide in the faqs. The target afr is that the one displayed when the dash showing? While I was playing I noticed it change figures a few times too? Is it reading from either the VE table or the warm up table? Is that why the figures change?

[VL400]

The VE table is the Volumetric Efficiency (VE) table, its not an AFR table.

The target VE is determined by a number of things, and will change depending on warmup, idle etc. There is a target AFR table for normal running, an idle AFR table for idle and then some warmup offsets. Do not play with these tables until you have a need to and understand them.

What you see in the data stream as Target AFR in TunerPro is what the ECU is trying to target. It needs to work how much fuel to inject for how much air it is consuming to get that target AFR so some calculations are done, one part of the calc takes in to account the VE of the engine that you have set in the VE table.

Have you read the 12P tuning guide? http://pcmhacking.net/forums/viewtopic.php?f=28&t=1089

[vc81]

Thanks mate. Yes I have read the basic tuning guide. Does anyone know if there are any video tutorials that show how to tune the VE table etc? Im still not sure I'm doing it right.

[Holden202T]

heres a target AFR for you compared to a wideband. (bottom monitor, red = target afr, green = wideband)

gemini 8psi boost run WSID.jpg (187.22 KiB) Viewed 4724 times

the trick with it is making sure the minimum and maximums in TP5 adx are all the same so they scale exactly the same on the monitor. as you can see TAF and AWB on the axis have the same numbers in the same spots. and this shows perfectly for me over the 1/4 mile pass that my fueling is pretty closely following the target but could do with some tweaking of the VE tables to get it spot on the whole way.

you also use the target and wideband to work out the percentage offset for VE's then multiply it by current VE to get a histogram of calculated VE which VL400 has added to most adx's I believe.

[vc81]

Is there any way to do this without the wideband wired into the ECU? As in only use the reading on the wideband gauge itself?