Hey everyone!
in an effort to build a better wealth of information regarding M20 MegaSquirt setups, I'm proposing a MegaSquirt general information thread. Since we already have a pretty good thread geared towards ignition and fuel maps, I'm hoping we can fill in some of the blanks in the less covered settings and features tabs that people teaching themself to tune (like myself) may be struggling with. Common issues or uncommon issues regarding E30 specific hardware, and things of that general nature are welcomed as well.
For the format;
I'll kick things off!
Engine Specs: 1989 M20B25 (Stock)
Megasquirt Version: MSPNP (MS2/Extra)
Engine/Relevant Mods: Cat delete, Billy Boat resonators and mufflers (off of an e34 535i exhaust system), AFM delete (using stock airbox bored out to 3" intake size), GM IAT, Innovate LC2 Wideband, Built in MAP.
Turbo: N/A
Boost Level:N/A
Injectors:19lb Bosch Gen III
Issue I've found proven solution for:
When I first started attempting to setup the Megasquirt after initial installation, I had an issue with the car beginning to misfire above 4200RPM. It sounded like ignition cut, but with a slow roll on instead of a hard cut. After checking to make sure it had good fuel pressure and that the fueling amount was within normal range, I started looking into ignition issues that could occur and began researching dwell. Turns out the basemap provided from DIYAutotune starts you off with 3.7MS nominal dwell. After doing more research on dwell and max spark durations, I learned that for a single coil distributor setup that my max spark duration was actually much shorter than what the base maps 3.7ms Nominal Dwell provided for. I ended up changing my 'Nominal Dwell' to 2.1, and Spark Duration to 1.0ms and the misfire at high RPM's has completely disappeared.
Issue I am currently struggling with:
I cant seem to get a consistent idle for the life of me. I'm not sure what frequency works best with the stock IAC valve, but right now I have it set at 252hz. It idles well enough with the Open Loop setting, but I dont have nearly the same control over target idle and warmup conditions as I would like. I got it to work extremely well for a little bit, but then ran into an issue where it seemed like the ECU would lose control of the IAC and the engine would idle at 2000 - 3000 RPM. Once I turned the car off and back on again however the idle would go away. The problem was also only present between 1/4 and 2/4 marks on the temp gauge. At operating temperature it idled buttery smooth. Trying to fix the random high idle issue just led me back to a fluctuating idle again. If anybody has a screenshot of working settings idle control and closed loop idle settings, I'd be so appreciative.
Hope you guys like the thread idea!
in an effort to build a better wealth of information regarding M20 MegaSquirt setups, I'm proposing a MegaSquirt general information thread. Since we already have a pretty good thread geared towards ignition and fuel maps, I'm hoping we can fill in some of the blanks in the less covered settings and features tabs that people teaching themself to tune (like myself) may be struggling with. Common issues or uncommon issues regarding E30 specific hardware, and things of that general nature are welcomed as well.
For the format;
- Engine Specs:
- Megasquirt Version:
- Engine/Relevant Mods:
- Turbo:
- Boost Level:
- Injectors:
- Issue you've found proven solution for:
- Issue you are currently struggling with:
I'll kick things off!
Engine Specs: 1989 M20B25 (Stock)
Megasquirt Version: MSPNP (MS2/Extra)
Engine/Relevant Mods: Cat delete, Billy Boat resonators and mufflers (off of an e34 535i exhaust system), AFM delete (using stock airbox bored out to 3" intake size), GM IAT, Innovate LC2 Wideband, Built in MAP.
Turbo: N/A
Boost Level:N/A
Injectors:19lb Bosch Gen III
Issue I've found proven solution for:
When I first started attempting to setup the Megasquirt after initial installation, I had an issue with the car beginning to misfire above 4200RPM. It sounded like ignition cut, but with a slow roll on instead of a hard cut. After checking to make sure it had good fuel pressure and that the fueling amount was within normal range, I started looking into ignition issues that could occur and began researching dwell. Turns out the basemap provided from DIYAutotune starts you off with 3.7MS nominal dwell. After doing more research on dwell and max spark durations, I learned that for a single coil distributor setup that my max spark duration was actually much shorter than what the base maps 3.7ms Nominal Dwell provided for. I ended up changing my 'Nominal Dwell' to 2.1, and Spark Duration to 1.0ms and the misfire at high RPM's has completely disappeared.
Issue I am currently struggling with:
I cant seem to get a consistent idle for the life of me. I'm not sure what frequency works best with the stock IAC valve, but right now I have it set at 252hz. It idles well enough with the Open Loop setting, but I dont have nearly the same control over target idle and warmup conditions as I would like. I got it to work extremely well for a little bit, but then ran into an issue where it seemed like the ECU would lose control of the IAC and the engine would idle at 2000 - 3000 RPM. Once I turned the car off and back on again however the idle would go away. The problem was also only present between 1/4 and 2/4 marks on the temp gauge. At operating temperature it idled buttery smooth. Trying to fix the random high idle issue just led me back to a fluctuating idle again. If anybody has a screenshot of working settings idle control and closed loop idle settings, I'd be so appreciative.
Hope you guys like the thread idea!
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