Megasquirt Anyone have an MSQ for a 13b with 750 primaries and 1680 secondaries?
Thread Starter
Joined: Dec 2007
Posts: 1,714
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From: Ortonville, MI
Anyone have an MSQ for a 13b with 750 primaries and 1680 secondaries?
Anything would be appreciated even if its 720s and 1600s, I just need something similar to analyze to help me tune.
Rotary Enthusiast
Joined: Jan 2002
Posts: 845
Likes: 38
From: Oscoda, MI
I don't have an MSQ for those spec injectors (mine are Denso yellow-body 450cc and Bosch EV14 650cc), but I did come across a few rookie mistakes that can cause problems.
1. If you import the AFR table for an MS2 into TunerStudio, make sure the AFR target values are correct. When I imported the table with AFR values into a table with Lambda values, it incorrectly calculated the Lambda values; I didn't notice this until I noticed that it was running rich at cruising speeds. Remember that Lambda = AFR/AFR stoich.
2. If you're using warmup enrichment, the last box at operating temperature must be set to 100. Otherwise, WUE will always stay on. Remember that with WUE on, it'll add additional fuel on top of the fuel map values in %. With WUE stuck on, if you increase all the values to insane numbers in WUE, you end up reducing the corresponding values in the fuel map; skewing your fuel map.
3. If running an NA, OEM emissions solenoids designed for engine vacuum will not handle air pressure from an air pump. I ended up clogging one and jamming another. One of the outputs on my MS3 drives a solenoid that allows air from the air pump to open the auxiliary (5th/6th) port valves. If the solenoid fails, the values won't open. The result is that you don't see enough air at high RPM, restricting engine speed to 6900 RPM, reducing power and thus affecting the tuning of your fuel map. While you can wire your ports open, this has the effect of reducing power at low RPM and increasing fuel in that area, wasting fuel as a result. Hooking the air pump directly to the values will not work either, they'll open at approximately 1800RPM. I ended up buying a cheap ($11 shipped, $5 for the unt) solenoid that works perfectly. I have it mounted away from the exhaust header.
1. If you import the AFR table for an MS2 into TunerStudio, make sure the AFR target values are correct. When I imported the table with AFR values into a table with Lambda values, it incorrectly calculated the Lambda values; I didn't notice this until I noticed that it was running rich at cruising speeds. Remember that Lambda = AFR/AFR stoich.
2. If you're using warmup enrichment, the last box at operating temperature must be set to 100. Otherwise, WUE will always stay on. Remember that with WUE on, it'll add additional fuel on top of the fuel map values in %. With WUE stuck on, if you increase all the values to insane numbers in WUE, you end up reducing the corresponding values in the fuel map; skewing your fuel map.
3. If running an NA, OEM emissions solenoids designed for engine vacuum will not handle air pressure from an air pump. I ended up clogging one and jamming another. One of the outputs on my MS3 drives a solenoid that allows air from the air pump to open the auxiliary (5th/6th) port valves. If the solenoid fails, the values won't open. The result is that you don't see enough air at high RPM, restricting engine speed to 6900 RPM, reducing power and thus affecting the tuning of your fuel map. While you can wire your ports open, this has the effect of reducing power at low RPM and increasing fuel in that area, wasting fuel as a result. Hooking the air pump directly to the values will not work either, they'll open at approximately 1800RPM. I ended up buying a cheap ($11 shipped, $5 for the unt) solenoid that works perfectly. I have it mounted away from the exhaust header.
Rotary Enthusiast
Joined: Jan 2002
Posts: 845
Likes: 38
From: Oscoda, MI
Quoting from Aaroncake's MS2 writeup:
How To Megasquirt Your 2nd Gen RX-7: Programming The ECU (MS2)
"The AFR table provides air/fuel ratio targets for the Megasquirt to follow when operating under closed loop. With a wideband sensor the Megasquirt is able to work to achieve a variety of AFRs, not just 14.7 as it would with a narrowband. The ratios presented in this table are a very good starting point. It is really only the cruise area we are concerned with (the area showing AFRs of around 15:1) as the Megasquirt is set to go open-loop everywhere else. "
If you are using TunerStudio's Autotune or Megalogger's VE Analyze fuctions, the AFR table is needed as it contains the target Air to Fuel ratios at various engine loads and speeds. So yes, you need to import the AFR table, just make sure the ratios are correct. Otherwise, you'll have issues.
How To Megasquirt Your 2nd Gen RX-7: Programming The ECU (MS2)
"The AFR table provides air/fuel ratio targets for the Megasquirt to follow when operating under closed loop. With a wideband sensor the Megasquirt is able to work to achieve a variety of AFRs, not just 14.7 as it would with a narrowband. The ratios presented in this table are a very good starting point. It is really only the cruise area we are concerned with (the area showing AFRs of around 15:1) as the Megasquirt is set to go open-loop everywhere else. "
If you are using TunerStudio's Autotune or Megalogger's VE Analyze fuctions, the AFR table is needed as it contains the target Air to Fuel ratios at various engine loads and speeds. So yes, you need to import the AFR table, just make sure the ratios are correct. Otherwise, you'll have issues.
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