Forum » Link G4 Plus Software Tutorial » G4+ MAF as load

G4+ MAF as load

Link G4 Plus Software Tutorial

Discussion and questions related to the course Link G4 Software Tutorial


Page 1
Author
155 Views

Hi, how do you set MAF as load. Subaru WRX LINK V5-6.

Looking at analogue inputs I can assign MAF as an input but in Fuel Main > Equation Load Source the options are MAP, BAP or BAP/MAP.

Thought this was supposed to be PnP.

Thanks.

You can use MAF if you wish, but the recommended option is MAP. The base map is set up for MAP and it should just work. The factory MAP sensor is good for about 18psi boost.

To use MAF, set equation load source to BAP. Set AN Volt 2 to MAF, set calibration to Subaru V7-9, change fuel table Y axis to Air per cylinder measured.

Thank you, what about the ignition table, presumably I need to change the load axis there too?

I wired in an charge air temp sensor last night when I gave up on using MAF. I wired this using the expansion loom (as read something about not being able to do it directly without a separate pullup resistor). I did set MAP to version 7 and it calibrated fine, calibrated TPS also. Stayed up late last night (UK time) and couldn't get the engine started.

Very confused about the traditional vs modeled fuel equation. Is the base map set up as 'traditional'? To me traditional is ms pulse width in the fuel table but not understand that the number in the fuel table is % of master fuel at MAP of 100kpa.

I really don't understand the need for a target lambda table in open loop (we don't have a wideband wire to the ECU) is this only used in the modelled fuel equation?

Please can you explain a little more the modelled fuel equation.

Thanks.

Thank you, what about the ignition table, presumably I need to change the load axis there too?

Yep.

Stayed up late last night (UK time) and couldn't get the engine started.

Was there realistic RPM displayed in the software when you were cranking it? The most common problem I used to see on the V5/6 was some models have the cam/crank sensors wired to different pins. There are some dip switches on the PCB to swap between the two options. If you have unstable or unrealistic cranking RPM then try these in the alternate position.

Very confused about the traditional vs modeled fuel equation. Is the base map set up as 'traditional'? To me traditional is ms pulse width in the fuel table but not understand that the number in the fuel table is % of master fuel at MAP of 100kpa.

The base map is set up in traditional mode. Traditional is pulse width based. You have a master fuel number that is in mS and that is multiplied by MAP and the fuel table number. So if you have a master fuel of 12mS and 50% in the fuel table and you are at 100Kpa (1 atmosphere) your final PW at the injector would be 12 x 50% x 1 = 6mS. If you car idles at 50kpa, and you still had 50% in the fuel table, it would be 12mS x 50% x 0.5 = 3mS.

I really don't understand the need for a target lambda table in open loop (we don't have a wideband wire to the ECU) is this only used in the modelled fuel equation?

You can turn off the open loop lambda target table if you wish but it makes tuning easier and flattens out the fuel map so it is generally recommended to use it. Basically the target lambda becomes a multiplier in the fuel calculation. So as an example how it works, lets say you have completely tuned your fuel table so that your measured lambda matches the target lambda under most conditions. Under cruise conditions your original target lambda was 0.95. Now you want to try it at 1.00 lambda instead, you just go to the target lambda table and change the target to 1.00 - the ECU will automatically adjust the inj PW and the lambda will match the new target without you having to retune the fuel table.

Please can you explain a little more the modelled fuel equation.

Modelled is a VE type equation where the "fuel table" actually represents the volumetric efficiency (how much air the engine flows) rather than how much fuel it needs. From the VE it can calculate the mass of air entering the engine, then calculate the correct mass of fuel to add. It takes a lot more factors into the equation such as the charge cooling effect of the fuel, injector flow rates and other characteristics, fuel density and temperature etc so can produce a more accurate fuel tune. The modelled fuel table will typically cover a different range of numbers and will have a different shape to a traditional fuel table so you cant just switch from one mode to the other without changing the fuel table.

I suggest you put most of the settings back to how they are in the base map and first confirm the basics such as the RPM I mentioned above. If still no go then attach a log of it cranking.

Thank you, what about the ignition table, presumably I need to change the load axis there too?

Yep.

Stayed up late last night (UK time) and couldn't get the engine started.

Was there realistic RPM displayed in the software when you were cranking it? The most common problem I used to see on the V5/6 was some models have the cam/crank sensors wired to different pins. There are some dip switches on the PCB to swap between the two options. If you have unstable or unrealistic cranking RPM then try these in the alternate position.

Very confused about the traditional vs modeled fuel equation. Is the base map set up as 'traditional'? To me traditional is ms pulse width in the fuel table but not understand that the number in the fuel table is % of master fuel at MAP of 100kpa.

The base map is set up in traditional mode. Traditional is pulse width based. You have a master fuel number that is in mS and that is multiplied by MAP and the fuel table number. So if you have a master fuel of 12mS and 50% in the fuel table and you are at 100Kpa (1 atmosphere) your final PW at the injector would be 12 x 50% x 1 = 6mS. If you car idles at 50kpa, and you still had 50% in the fuel table, it would be 12mS x 50% x 0.5 = 3mS.

I really don't understand the need for a target lambda table in open loop (we don't have a wideband wire to the ECU) is this only used in the modelled fuel equation?

You can turn off the open loop lambda target table if you wish but it makes tuning easier and flattens out the fuel map so it is generally recommended to use it. Basically the target lambda becomes a multiplier in the fuel calculation. So as an example how it works, lets say you have completely tuned your fuel table so that your measured lambda matches the target lambda under most conditions. Under cruise conditions your original target lambda was 0.95. Now you want to try it at 1.00 lambda instead, you just go to the target lambda table and change the target to 1.00 - the ECU will automatically adjust the inj PW and the lambda will match the new target without you having to retune the fuel table.

Please can you explain a little more the modelled fuel equation.

Modelled is a VE type equation where the "fuel table" actually represents the volumetric efficiency (how much air the engine flows) rather than how much fuel it needs. From the VE it can calculate the mass of air entering the engine, then calculate the correct mass of fuel to add. It takes a lot more factors into the equation such as the charge cooling effect of the fuel, injector flow rates and other characteristics, fuel density and temperature etc so can produce a more accurate fuel tune. The modelled fuel table will typically cover a different range of numbers and will have a different shape to a traditional fuel table so you cant just switch from one mode to the other without changing the fuel table.

I suggest you put most of the settings back to how they are in the base map and first confirm the basics such as the RPM I mentioned above. If still no go then attach a log of it cranking.

Thank you, most helpful.

I think you're onto something with the cank signal dip switch.

I'd forgotten to be honest but on v5-6 GEMS have an option to switch cam and crank signal, think this is dependent on whether the car had factory immobiliser...?