rider384

iTrader: (3)

Running on a brain-built DIYMS-I. 460cc '88 RX7 injectors

Car has always ran 100% spot on except for very high AFRs at idle (17:1 and I couldn't bring them down at all). Finally figured it out - opened up required fuel calculator and it was set at 8 cylinders. Reset to 4. All of a sudden AFRs dropped to 14.5:1 at idle, exactly what they were supposed to be.

Fast forward to this morning. Started the car. The changes in tuning meant it no longer died out at idle until it warmed up a bit (old tune leaned out at idle and would die with any throttle until 20 or 30 seconds after starting). I get going. Car is just fine, cruising at 13.5-14:1. Have not gotten into boost at this point as it is still cold.

Stop to get gas. Car is warmed up at this point. I take off out of the station exit onto the main road and notice the car doesn't want to go. I manage to get it up to cruise speed and noticed it was at ~ 10:1 AFR. At cruise, while fully warmed up. Any throttle it'd drop to ~7.5-8:1. Stumbled bad. It was actually faster under partial throttle than WOT.

I need this by Saturday, I've got a dyno.

tl;dr version:
-Car always idled at 17:1. Could not get it down
-Realized MS was set to 8cyls instead of 4, changed it. Idle was now perfect
-Car drove fine while cold, good AFRs
-Warmed up, started running PIG rich. As in 10:1 at cruise and 8:1 at load.

Thoughts?

Also, I am, unfortunately, not at home right now, so I can't post any settings. What I can remember is that, apart from the number of cylinders, all of my other required fuel calculations were accurate, and it always ran fine on 8cyl mode except for the idle...

Braineack

iTrader: (62)

the calculator will always show the default settings the first time you open it. it's just a calculator which changes the req_fuel value. What did you change it from and to?

To reiterate: you weren't running in 8cly mode, you just altered the multiper of your fuel map. I assume you increased your req_fuel number, so you increased the amount of fuel you are injecting all things being equal.

lets say your fuel map at idle is 30% VE. your req_fuel was 6.

6 x .30 = 1.8ms of fuel

now that you fucked with it and say increased it to 12...

12 x .30 = 3.6ms of fuel.

twice the amount of fuel at idle with the same fuel map. Imagine what the does in boost...



My suggestion to you is to change the number back, should be like 5.9 (can't remember off the top of my head) and tune your fuel table, BY HAND, for idle.

pdexta

iTrader: (17)

This may be a stupid question, but have you datalogged and run VE Analyzer in MegaLogViewer? From what you're describing it sounds like you haven't let the software tune the car at all. The only thing your Req Fuel gives the computer, as far as I know, is a basis for how much fuel it needs (this compensates for injector size, cylinders, CC's to allow us to get the car running on a basemap in order to start the tuning process).

rider384

iTrader: (3)

I will check the required fuel again, but apart from changing it from the 8 to 4, I literally did not TOUCH anything. The only two things I did last night were change the second output of my LC1 to 0-5v and number of cyls from 8 to 4. Though if I'm having this problem, I probably did...

Any other suggestions? I'm 30 miles away from home right now. At 3 I am dropping by a friends house to use his laptop to check **** out. I do not have a lot of time.

rider384

iTrader: (3)

I have not. I thought it was to compensate for injector size and displacement so it knows how long to fire the injectors for in order to achieve desired AFRs? But I really know nothing about it.

Braineack

iTrader: (62)

If you opened the calculator and clicked burn/calculate, it changed the loaded req_fuel value.

If you didn't atler the other settings, like motor size, injector size, and stoich AFR the value won't be correct for your motor.

If you change the req_fuel value back, everything will go back to normal. To fix your lean idle, you should be adding fuel into your VE fuel table 1 in the cells where you idle at.

rider384

iTrader: (3)

I tried, at one point, to do this. I DUMPED fuel into the idle cells. I got down to 11:1ish and it still sat in the 17s.

I will check the values when I get to the computer.

Braineack

iTrader: (62)

how can afrs get down to 11:1 and 17:1 at the same time?

rider384

iTrader: (3)

Sorry, bad wording. According to the map it should have been 11:1 but it still sat in the 17s according to my LC1

Jeff_Ciesielski

iTrader: (10)

Still makes no sense. How would you know what AFR it should have been at?

Do you mean the AFR Target table?

rider384

iTrader: (3)

Yeah

Braineack

iTrader: (62)

that means little.

you need to alter the actual VE fuel table 1.

you probably dont even have EGO on at idle, and you shouldn't.

rider384

iTrader: (3)

This thread makes me realize how little I know.

What is EGO?

Also, what is the difference between the VE target table and the AFR target table?

Braineack

iTrader: (62)

<MUHAHAHAHAHaHaHaHaHahaHAHAa

pdexta

iTrader: (17)

When you are in tunerstudio, I believe it's: Basic Settings > Fuel VE Table and you'll pull up your fuel map. With the car running at idle you should see a yellow cell/cells, that indicates where your car is on the map at that given time. If it's running too lean, increase the number in the cells that are yellow (should be in the lower left hand corner of your map at idle). Increase them until you get the AFR that you desire.

In order to tune the rest of your map. Go to datalogging > start logging. Drive around for 10 minutes. Then go to datalogging > stop logging. Close tunerstudio and open megalogviewer. Go to "open MSQ" and select your current tune. Click on "ve analyzer", and "run analysis". This will use your AFR target tables to adjust your current map. Once it's done you will see cells show up in red that have been decreased and blue(?) that have increased. Review the changes, click "accept settings". Then Save MSQ as, and save it as something to distinguish it from the previous tune. Go back into tunerstudio and go to "open tune" it's in one of the menus in the upper left corner, I can't remember offhand which one. You can then select the tune and burn to the computer. Your new tune will be loaded and you can repeat the process. After doing this a few times for the most part your fuel map will be exactly as you want it.


*Edit - I cannot gaurantee this is the best way to do it, but that's how I do it, and so far all the pieces of my motor are still inside my motor.

Jeff_Ciesielski

iTrader: (10)

The AFR Target table is the table that tells your car what AFR to shoot for when in closed loop mode (cruising for example). It is also used by megalogviewer and VE Analyze Live to automatically correct your fuel table during auto-tune.

In open loop mode (normal driving around, WOT pulls, etc) the car relies on the VE target table to determine fueling.

To oversimplify -> The VE table is how much fuel to inject, and the AFR Table is for corrections.

Now, as for how to fix your problem: Go to the req_fuel calculator, and cut your req_fuel# in half, this should bring things back into acceptable range. req_fuel is only used to scale your map so that all values fall between 0-255, in the grand scheme of things though, it doesn't mean much. You could set it to 5 or 15, and as long as the VE table is tuned properly, it won't matter. After that, go to fuel settings-> VE Table 1 while the car is running, and you should see a little yellow dot (as pdexta pointed out). At idle, select the cells that are lit up and use the up/down arrows to increase or decrease the amount of fuel that should be injected.

People still use MLV to autotune fuel? I thought it was pretty standard practice to use VE-A live at this point....

rider384

iTrader: (3)

Could I see someone's VE table?

I am on a computer with TS now, and I happened to have a copy of my tune in my email.

Braineack

iTrader: (62)

its going to vary significantly from car to car.


but the ve fuel table is your main fueling map. changes there will have direct effect on your AFR and determining your pulsewitdh.

I simplified it previously. Where req_fuel x VE% x MAP reading + Enrichments = Pulsewitdh

The AFR targets table is for fune tuning closed loop. Those will factor into the enrichments part of the equation. The O2 sensor reports into the MS, the MS compares it to the AFR targets table and then increases/decrease fuel on-the-fly to try to acheieve the number you are asking of it.


If your tune driving around was good, but idle was lean, go back to the req_fuel number you had before the change. Then open the VE table 1 at idle, and add in fuel in the area that's hightlighted in yellow. Do it little at a time until the AFRs get to an area that's closer to 14-14.5:1.

rider384

iTrader: (3)

What do the numbers in the VE table represent? As in, what are the units? I would like to understand it before I start making changes to the base map that has worked for me for a year.

Braineack

iTrader: (62)

http://msextra.com/doc/ms1extra/MS_E..._Manual.htm#ve