Basic settings for 3 wire Bosch ICV

[kristov]

Does anyone have any basic settings for this that I can start with?

The engine is a 3.2L 24V inline six from BMW. I think the stock idle is around 1000 rpm when cold.

[Kelly2264]

What ECU are you using and what version chip?

[MRMRacing]

You can read my post at http://www.mrm-racing.se/forum/showthread.php?t=137&highlight=iac+setting&page=2
and http://www.mrm-racing.se/forum/showthread.php?t=52

[kristov]

It's an SM4, how can I find the chip version?

[kristov]

I have now started the engine but I experience a pulsating idle rpm. I also feel a strong vaccum pulsating from the intaketube of the ICV.

When I first start it, it runs great for 1-2s. After that it starts pulsating.

If I just barely give it some throttle it runs great.

I think this must be something with the tuning of the ICV.:confused:

Could someone please look at my CAL and see if something is wrong?

[MRMRacing]

I have made some changes in IAC control .You can this.

[kristov]

I have made some changes in IAC control .You can this.

Thanks, I will try this!

Just thought about another thing.

I use TPS as the only load sensor for fueling and have now been told that this will not work with an ICV, since the the air drawn by the ICV will be like a "vacuum leak" because air is only measured by TPS opening.

Is this true?:confused:

[MRMRacing]

What do you mean? You have BAro & Map and the mapsensor should be connected so the fuel is from both TPS & MAP pressure.

[kristov]

What do you mean? You have BAro & Map and the mapsensor should be connected so the fuel is from both TPS & MAP pressure.

Base fuel delivery is calculated from Throttle position if you look in the cal.

Is this not the optimal settings for my eninge?

The engine is a 6 cylinder 3.2L 24V with ITB's. I am currently running this only as a naturally aspirated engine.

[Chris]

Is the map sensor connected to the intake manifold ?

If you want to run TPS only not TPS/MAP then in M1/Base Settings/Primary fuel method set to "Baro & Tps" . You will have to remap the engine.

Please verify the current situation with regards to the map sensor.

Chris

[kristov]

Is the map sensor connected to the intake manifold ?

If you want to run TPS only not TPS/MAP then in M1/Base Settings/Primary fuel method set to "Baro & Tps" . You will have to remap the engine.

Please verify the current situation with regards to the map sensor.

Chris

Hi, thanks for the reply!

The map sensor is not connected yet and the engine is not mapped.

I just want to make sure I pick the optimum settings before mapping the engine.

[Chris]

If you run that engine "Baro &TPS" you will need to change the load axis in base timing and target afr to TPS

Chris

[MRMRacing]

When using Baro & Map you should have the map sensor connected! If using Baro & TPS Map sensor are not connected and normally I/P Baro is set to sensor. You set fuel/ign/AF tables then to TPS.
For your app I would connect the mapsensor and use Baro & Map and tps at fuel table or Load if you got stable vacuum at idle.

[kristov]

If you run that engine "Baro &TPS" you will need to change the load axis in base timing and target afr to TPS

Chris

I understand that, but which setting will yield the best results with my engine (horsepower, response, drivability)?

So which one should I choose BARO + MAP or BARO + TPS?

[Chris]

I understand that, but which setting will yield the best results with my engine (horsepower, response, drivability)?

So which one should I choose BARO + MAP or BARO + TPS?

BARO+MAP with base fuel delivery axis set as TPS. Connect the MAP.

Chris

[kristov]

BARO+MAP with base fuel delivery axis set as TPS. Connect the MAP.

Chris

Thanks, is this then some sort of Alpha-N blend or speed density?

[kristov]

When using Baro & Map you should have the map sensor connected! If using Baro & TPS Map sensor are not connected and normally I/P Baro is set to sensor. You set fuel/ign/AF tables then to TPS.
For your app I would connect the mapsensor and use Baro & Map and tps at fuel table or Load if you got stable vacuum at idle.

Thanks, should I use tps, load or map for ignition map?

[Chris]

Thanks, should I use tps, load or map for ignition map?


I would normaly use load. Also note these help comments from "Baro press estimate" table.


If ECU has no extra baro sensor, then ECU can estimate the baro pressure by specifying the pressure drop accross the butterfly.
Recommended when throttle/pressure mapping a non turbo engine.


Chris

[MRMRacing]

Use load on ignition so it will be the "actual" need that controls ignition and not you "foot":D

The Baro&Map and TPS on fuel with map sensor connected is very good and works with turbo also. If you get very stable vaccum at idle you can try load here.

[kristov]

Use load on ignition so it will be the "actual" need that controls ignition and not you "foot":D

The Baro&Map and TPS on fuel with map sensor connected is very good and works with turbo also. If you get very stable vaccum at idle you can try load here.

Hehe, what was I thinking...

Seems like I'm all set for som testing tomorrow then :cool:

When running this configuration is it some sort of Alpha-N blend or speed density?

[Chris]

Thanks, is this then some sort of Alpha-N blend or speed density?

Speed density refers to rpm/manifold (pressure/temperature)

Alpha-N or N-alpha I believe refers to throtle position used as load input. I see that more in British literature.

Using BARO +MAP with primary fuel table axis set as TPS is an excellent setup. It gives you fuel correction for changes in manifold pressure at fixed throttle position .

Would I call that Alpha-N blend ? We generally call it Throttle/Pressure mapping

Chris

[kristov]

Speed density refers to rpm/manifold (pressure/temperature)

Alpha-N or N-alpha I believe refers to throtle position used as load input. I see that more in British literature.

Using BARO +MAP with primary fuel table axis set as TPS is an excellent setup. It gives you fuel correction for changes in manifold pressure at fixed throttle position .

Would I call that Alpha-N blend ? We generally call it Throttle/Pressure mapping

Chris

Ok, I just ask since usually Alpha-N gives better throttle response and speed-density better drivability.

I'm greedy and would want both things if possible.:cool:

[Wroom]

I use TPS as the only load sensor for fueling and have now been told that this will not work with an ICV, since the the air drawn by the ICV will be like a "vacuum leak" because air is only measured by TPS opening.

Is this true?:confused:
When the engine is fairly mapped, you should adjust the "IAC extra fuel" under "IAC tuning" so that the engine maintains a decent AF ratio when the IAC operates. Put first gear in, and then engage clutch. If the AF lean out when you load the engine at idle so the IAC dials out, then add some percent to the "IAC extra fuel" until AF stays at decent values when loading the engine at idle. This way you get good driveability with IAC and TPS mapped combo.

[kristov]

When the engine is fairly mapped, you should adjust the "IAC extra fuel" under "IAC tuning" so that the engine maintains a decent AF ratio when the IAC operates. Put first gear in, and then engage clutch. If the AF lean out when you load the engine at idle so the IAC dials out, then add some percent to the "IAC extra fuel" until AF stays at decent values when loading the engine at idle. This way you get good driveability with IAC and TPS mapped combo.

Thanks for clearing that up, as I have been convinced that Throttle/Pressure mapping is the best method for my engine I will not use Alpha-N (BARO + TPS).

[kristov]

I would normaly use load. Also note these help comments from "Baro press estimate" table.


If ECU has no extra baro sensor, then ECU can estimate the baro pressure by specifying the pressure drop accross the butterfly.
Recommended when throttle/pressure mapping a non turbo engine.


Chris

How do I find/measure this value?

[Wroom]

Thanks for clearing that up, as I have been convinced that Throttle/Pressure mapping is the best method for my engine I will not use Alpha-N (BARO + TPS).
It still applies when using Throttle/Pressure mapping.

[kristov]

Tried the modified CAL from MRM today with the MAP connected - still the same problem.

The car idles great for the first 10-20s with AFR around 13. This is from a cold engine.

After that the IAC goes crazy and seems to compensate up/down all the time making the engine pulsating between 1000 and 500 rpm. I Also notice the AFR is very high, around 20.

I then try to add fuel (in the main fuel table) and as I get closer and closer to 14.7 AFR the engine begins to pulsate even more.

If I just give it som throttle to bypass the IAC it runs fine.

Any ideas?

[MRMRacing]

Are u sure you do not have the wires to the IAC in opposite order. You can change the inverted output to the other.

[kristov]

Are u sure you do not have the wires to the IAC in opposite order. You can change the inverted output to the other.

I wired the IAC as per instructions in the SM4 manual. I can try to change the inverted output though.

[MRMRacing]

Else we would need a log of all IAC parameters to see what is going on!