Rice's MS thread

[Lex]

Start by lowering the Req_Fuel variable by 0.2 and see what that does for you. Do this under the Engine Constants Menu.

[wheresthericego]

Question.
When making changes to the VE table, in what increments would be a safe adjustment?

Also do smaller increments have less impact on lower rpms then on high?

[Beerizfood]

Did you do the free air calibration for the LC-1?

[wheresthericego]

yes i did. exactly as innovate says too.
i lowered the req fuel by .2 which helped some then i did it again and it didnt seem to make a difference. im getting a rich reading cruising. at cruise im reading 11 afrs boost is around low 10s

[wheresthericego]

I've set the req_fuel down to 9.2 now I need to pull fuel from the idle. It idles very rich in the 11's.

Also I mounted the MS today in its final location. I don't like the OEM ecu location. I also don't need the ducts that go to the floor under the seats as I never have it on the "floor" setting so i took them out too.
The MS mounting holes are almost the same width as the holes for the vents. I had to drill a new hold about 1/8" inch wider.


The center console tray with the door is tight now. I might move the MS back off the vent mount holes depending on how annoying it gets with the door.



Also I wanted a "factory" look to the Wideband LED and the Calibrate button so I put it in a blank switch.

[Lex]

Look great Nate! Pull some fuel from the VE table in the 900-1200 RPM range and under 40Kpa pressure. That should lean your idle out.

You can also start running feedback from the wideband to have the A/Fs you want under cruise conditions.

[wheresthericego]

what do you mean running feedbak?

[Lex]

O2 feedback. So the car uses the O2 sensor to add or remove fuel so that you maintain a target AFR.

Have a read here about setting it up:

http://www.megamanual.com/megatune.htm#se

Once you enable EGO control under file you can set up an AFR target table as well under more settings to use with your wideband.

[wheresthericego]

Should I smooth out the VE table from the idle up?
It seems to idle pretty well now and is slightly less than 15 afr.
When I give it a quick rev from idle the afr will go very lean (18-20 afr) for a split second. Is that normal?
Also I was having problems with the hot starts so I increased the cranking pulse widths for 130° to 4.5 and 160° to 3.5. It seems to be slightly better.

[Lex]

Yup its normal to go lean for a split second until the injectors deliver the fuel. Take a buddy with you and go for a long drive and tune the entire table but don't do it just sitting still because you don't know the results and they might be surprising.

[wheresthericego]

I think I read that you cant tune the fuel table with the engine running. Is that true?

[matt_fulghum]

don't worry about the lean spikes too much... it is literally impossible to get rid of them, as they are an effect of the physics of the system.

There are numerous reasons for why the spike happens:
1. Airflow peak is actually at a maximum right before the throttle stops moving, so a slightly larger amount of air goes into the manifold than would otherwise have, however due to transport delays in the system the MAP sensor does not see this effect. This happens with any system, including carburetors.

2. Acceleration enrichment is designed to cope with the problem mentioned in number 1, above. TPS based acceleration enrichment can be used to tweak out some of the initial lean spike (because the ECU reacts to this immediately, as there's no real transport delay involved), and then MAP based enrichment should take care of the rest. However the extra fuel injected with the acceleration enrichment cannot evaporate fast enough (at least if you're running gasoline) so a fair sized chunk of it puddles in the cylinder head on the valves, and it takes a little while to work its way into the cylinder. Nothing you can really do about this either, aside from using a fuel with higher volatility (not practical unless this is a drag car).

There are a couple other minor reasons, but these are the biggies. Really, the point you should get out of the two statements above is that you can't really do anything about it short of making the ECU read your mind and find out when you want to accelerate. This effect happens in OEM ECUs too, you just don't worry about it until you see it first hand

[Lex]

don't worry about the lean spikes too much... it is literally impossible to get rid of them, as they are an effect of the physics of the system.

There are numerous reasons for why the spike happens:
1. Airflow peak is actually at a maximum right before the throttle stops moving, so a slightly larger amount of air goes into the manifold than would otherwise have, however due to transport delays in the system the MAP sensor does not see this effect. This happens with any system, including carburetors.

2. Acceleration enrichment is designed to cope with the problem mentioned in number 1, above. TPS based acceleration enrichment can be used to tweak out some of the initial lean spike (because the ECU reacts to this immediately, as there's no real transport delay involved), and then MAP based enrichment should take care of the rest. However the extra fuel injected with the acceleration enrichment cannot evaporate fast enough (at least if you're running gasoline) so a fair sized chunk of it puddles in the cylinder head on the valves, and it takes a little while to work its way into the cylinder. Nothing you can really do about this either, aside from using a fuel with higher volatility (not practical unless this is a drag car).

There are a couple other minor reasons, but these are the biggies. Really, the point you should get out of the two statements above is that you can't really do anything about it short of making the ECU read your mind and find out when you want to accelerate. This effect happens in OEM ECUs too, you just don't worry about it until you see it first hand

Well if it were drive by wire and the ECU controlled the throttle it wouldn't need to read your mind, it would make your mind up for you

[Lex]

I think I read that you cant tune the fuel table with the engine running. Is that true?

It's perfectly fine to tune with the engine running. That is how you are supposed to tune. Once you change a cell, the change takes effect the moment you move your cursor to a different cell. However unless you burn to the ECU you will lose all the changes once you turn the ignition key off. So just make all the changes on the fly while driving (teach your friend to make the changes while you are driving using the Tuning menu) and then pull over and burn while idling to make the changes permanent once you're happy with how it runs.

You can burn to the ECU while driving too but you will experience a jolt as the ECU resets. Just don't do it in a high load situation (like under boost).

[FamiliaGT]

After reading this thread, I am seriously itchy to get my MS system. This looks like it will be a very fun experience. Lex, your Customer support is top notch. Have any experience using MS on a BF 1.6l Turbo? I cant wait to do this upgrade!