VE Table odd

ae86cesar · Post by **ae86cesar** » Mon Dec 15, 2014 9:36 pm

Hi everyone,
ive been on and off working on my project car for years, recently i have tried to start the car and turns on only when i pump the gas pedal. i get it to idle just fine but the VE table values seem a bit too high. other VE tables ive seen the idle VE table values are around 30-40 while mine are at 100+, any input will be appreciated and remember im inexperienced but not new to megasquirt.

ae86cesar · Post by **ae86cesar** » Mon Dec 15, 2014 9:39 pm

here is my msq file,

slow_hemi6 · Post by **slow_hemi6** » Tue Dec 16, 2014 3:09 am

Is that 1.250mS dead time right?

DaveEFI · Post by **DaveEFI** » Tue Dec 16, 2014 4:06 am

Pretty well every VR table I've seen has progressively increasing cells. With the lowest number in the bottom left cell. Not set in stone - but a good starting point.

I'd be inclined to start off with a TS generated VE table and required fuel. Trim the req fuel figure until you get an good idle with that table. If you have to alter the req fuel figure by much, you need to find out why.

elutionsdesign · Post by **elutionsdesign** » Tue Dec 16, 2014 9:30 am

You have to understand that the VE table is a representation of airflow or Volumetric Efficiency. Would you expect, for example, your airflow to increase by 30-60% at 100 KPa moving from 1800 rpm to 2500 rpm and then suddenly drop back? No, it would increase certainly, but in a smooth and uniform manner. Cam events can make for odd peak flow in some areas but you'd never see huge numbers next to small ones. Turbo cars with turbines too small for the application have big flow in mid-rpm boost that tapers off as rpm's increase (less airflow due to turbine back pressure) so it doesn't always increase moving left to right but as a general rule the more air the engine is pumping (higher rpm) the more air is flowing.

That island in red in the middle isn't right in other words, part of the issue is the software is using not only the cell where it currently resides but all those around it. Sometimes VEAL can get a little crazy that way and make a "lumpy" table like that one.

suberimakuri · Post by **suberimakuri** » Tue Dec 16, 2014 12:35 pm

Is this a 4AGE in an AE86?

General settings:
2.4l motor with 295cc injectors. I think should be 1600cc (1587 or whatever).. so the req fuel is wrong.
4 squirts per cycle, change that back to 2.

Try this VE table. It's early tunings of a 4AGZE+Turbo running 550cc injectors. Good up to 100kpa and ~5500rpm. Above that rich!
Once you've got your Req Fuel sorted, it might run, or you might have to scale it a bit but the shape is typical of every near standard single throttle 4age install I've ever tuned.

ae86cesar · Post by **ae86cesar** » Tue Dec 16, 2014 5:20 pm

Actually it is ae86 car but I installed a 2.4l engine from a tacoma. That area around 30-40% and 750rpm with 100+ values I increased myself it was the only way I was able to start the car which is what I find odd..

suberimakuri · Post by **suberimakuri** » Tue Dec 16, 2014 5:24 pm

Okay.
Try changing the 4 squirts alternating to 2 squirts alternating.

ae86cesar · Post by **ae86cesar** » Tue Dec 16, 2014 6:44 pm

Thanks suberimakuri but won't that make it require more fuel? Also would a data log be of any help I'm going to make one that's less than 1mb to upload

ae86cesar · Post by **ae86cesar** » Tue Dec 16, 2014 7:19 pm

*update*

Changing from 4 squirts to 2 squirts makes the car not start at all. I tried accelerating and the engine sounds like it's missing, what should I look into. I'm going to check the plugs for now

suberimakuri · Post by **suberimakuri** » Tue Dec 16, 2014 7:27 pm

Yes but it's correct in my opinion.
Up your required fuel number manually to combat.
Sure post a data log. May be something else affecting commanded pulse width.
How are your injectors paired?
You have semi sequential turned on so they need to be 1+4, 2+3. Otherwise if 1+3, 2+4 like normal Toyota then need to use different setting under fuel menu.

I'll have another look at msq tonight.

billr · Post by **billr** » Tue Dec 16, 2014 7:41 pm

I'm offering a dissenting opinion... calculate the "req_fuel" using your correct flows and stoic, then leave it alone. If you need to change fueling, do that in the VE table or AFR table (with "use AFR" turned on). Have you flowed these injectors, and determined the correct dead-time? When it runs radically different going to different number of squirts, I first think of dead-time being off.

ae86cesar · Post by **ae86cesar** » Tue Dec 16, 2014 9:29 pm

Here is a data log of the car idling, and another with acceleration.

suberimakuri,
so the way i have my fuel/spark wired is bank1/spark1 on 1+3, and bank2/spark2 on 2+4 is this correct? im considering purchasing ms3x and going full sequential since im running Coil on plug.

Billr,
all i have been changing is the VE Table, but i am going to try to start a new tune from scratch tomorrow and see what that does.

thanks guys for the help

suberimakuri · Post by **suberimakuri** » Tue Dec 16, 2014 10:55 pm

Thanks. Will check at home.
I agree with above about setting required fuel, I just wanted to give an idea of a typical map for 4age, which will differ slightly seeing as yours is a 2.4.

Instead of sequential, use the sequenced batch fire under fuel menu.
Because of your injector pairing, sequential will fire injectors at wrong timing for two cylinders.

suberimakuri · Post by **suberimakuri** » Wed Dec 17, 2014 2:10 am

Okay had another look.
Nothing that spooky in the logs which is good.
EGO correction is running at 90% during end of the run, so potentially that's 10% you could drop the VE at idle.
We can see with startup enrichment higher pulsewidths than needed too. Leave startup as is though and adjust VE.
Definitely need to sort out VE table to have any chance with accel. I haven't used EAE so won't comment.

In the config attached I:
1) changed squirts back to 2 alternating.
2) changed sequential to sequenced batch fire.
3) smoothed out some of the VE table, this needs lots more work.
4) Turned off overrun. Turn it on after VE table dialed.
5) Turned on incorporate AFR.

I suggest:
a) Richen the AFR table 1 whole point until you know what the engine will take... like drop one whole point, 15.2:1 -> 14.2:1. It'll be safer for a start.
b) Turn off EGO and tune the VE table manually for idle. Aim for lowest MAP reading.
It may be popping from being too rich, which causes lean conditions on O2. What were the plugs like?
c) Smooth out your ignition timing, there's lumps off idle be conservative. Come back to it once AFR closer and stable.
d) Starting is a function of cranking rpm and cranking pulsewidths, you may need to increase both to get it to fire initially.

2RZ motor?

ae86cesar · Post by **ae86cesar** » Wed Dec 17, 2014 6:53 pm

Thanks I will try those settings, Yea its a 2rz motor with a supra transmission and Ford 8.8 should be fun.

ae86cesar · Post by **ae86cesar** » Wed Dec 17, 2014 7:28 pm

*update*

Suberimakuri,
With the tune you gave me the car fired right up I had to drastically lower the VE Table around idle from 100+ 0 values to 40s car still had problems with acceleration and I noticed my catalyc glowing red, could this cause that? Also when accelerating the afr drops to 10. I'm thinking this may be the problem now I need to remove it and tune without it. Ran out of gas for today. Will try again tomorrow.

Thank you very much!

suberimakuri · Post by **suberimakuri** » Thu Dec 18, 2014 12:39 pm

Great.
Sorry I wouldn't call it a tune but sounds like you're on the way. Good one.
Dunno about the cat, I take them out. Might have got a lot of fuel in it.
Read the manual about tuning and work through I think best

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