I'm at the end of my rope with this BMW

750Li (N62B48). I've been fighting a crank-no-start for months and I'm burned out. The car cranks strong, injectors fire,

RPM signal is present, but there is absolutely no spark.

I've already checked everything I can:

* Crank sensor (good signal)
* Cam sensors
* Coils and plugs
* IVM power distribution
* DME power and grounds
* KL87/KL15 behavior

The weird part: I'm seeing ground instability on the coil harness. The brown ground wire shows voltage activity during crank, which makes no sense.

DME never triggers the coils.

After unplugging Battery and DME for testing, the car even went into an ignition lockout where the key won't wake the car or even click.

I'm exhausted and out of ideas. I need someone who actually understands N62 electrical issues, DME/IVM handshake, coil ground splice failures, KL87 logic, whatever.

If anyone has seen this exact no-spark situation or knows where the coil ground splice lives on the N62B48 harness, please help. I'm desperate for real answers at this point.

Hey all, wondering if my AFR target table is off, ive been using the ve analyze tool in tuner studio but I have a continual stumble on partial throttle low rpm high load and it seems to be right in the same area my arf target table drops wuite a bit, does this table look reasonable or does it need adjusted?

Hey!

Tuning my vvti swapped NA miata, motor out if a 2002 running on a BMM ecu.
Im running into an issue where anything above 4.5k rpm rev matching causes a stumble with a deep throttle blip, and shifting fast causes the motor to hesitate before going. I have to roll into the throttle for it to not do this. I can also just slam throttle above 4.5 and itll cause the same thing.
Effectively it takes a half second after 0->100% for the motor to start doing anything.

No amount of having AE/Wall wet disabled or enabled seems to do anything. Any ideas? Car runs fine at good afr on a normal pull.

I read a reply about a resistor in the O2 circuit. About what numbers on the EJK or power commander, etc.

But without a wideband O2 sensor, stoichiometer, and dyno, How do you know what your AF ratio is?

And if you can’t tell for sure, doesn’t it make sense just to run an exhaust that keeps the OEM O2 sensor?

ETA, if the KLX300R makes do without an O2 sensor, maybe between the MAP and the TPS the ECU knows what to do?

hello to everyone!

I just installed a megasquirt ms2 on my hyundai Scoupe, and I'm having some issues.

The main problem is that the car won't start, It cranks starts and stalls.

After trying and checking everything I could, I saw that when the ecu is using the VE map, the car pulse width goes directly to 0, and I don't know why. If I set a hight crankspeed, the cars "idle" but entering and exiting from the cranking mode.

Im new with this, and I will thank any support.

The ignition is correctly timed, injectors are correctyle configured (oem injectors).

This log is with 800 rpm cranking speed.

Thanks in advice

hello to everyone!

I just installed a megasquirt ms2 on my hyundai Scoupe, and I'm having some issues.

The main problem is that the car won't start, It cranks starts and stalls.

After trying and checking everything I could, I saw that when the ecu is using the VE map, the car pulse width goes directly to 0, and I don't know why. If I set a hight crankspeed, the cars "idle" but entering and exiting from the cranking mode.

Im new with this, and I will thank any support.

The ignition is correctly timed, injectors are correctyle configured (oem injectors).

This log is with 800 rpm cranking speed.

Thanks in advice

Trying to get my project done. Really tired of chasing little gremlins, but I'm hoping this one is something simple.

When I try to do a TPS calibration, all I get is 0 ADC for both closed throttle and wide open. I changed the throttle position sensor itself with a known good one (I ohmed out the pins while actuating it to see it sweep from 0.1Mohm to 0.41Mohm). I checked the pinout on the connector and I'm pretty sure it's right (1999 Saturn SL2). The only other thing I can think of is something is wrong in the ECU itself. Is there a test I can do to verify the circuitry on the board? (MS2 v3.0)

Thanks in advance!

Hi everyone,

I'm using a MAX9926 (Mode A2) to read a 5V digital Hall sensor running in parallel to a high-EMI CDI on a 170cc 2-stroke engine.

• IN+: Hall signal + 1kΩ pull-up to 5V.
• IN-: Biased to 2.5V via a 1kΩ voltage divider.
• Parts: Standard 0402 SMD resistors.

The Issue: CDI voltage spikes are causing the 0402 biasing resistors to permanently drift in value. This shifts the 2.5V reference on IN-, causing erratic readings and missed pulses at high RPMs.

Questions:

1. Hardware Strategy: Since the datasheet ignores digital inputs, should I just ditch the 2.5V bias divider and tie IN- directly to ground?
2. Protection: Is this strictly a voltage rating/arcing failure on the 0402s? Will upgrading to 0805/1206 thick-film resistors and adding an SMAJ5.0A TVS diode on the input line solve the drift?
3. Alternative: Is the MAX9926 too sensitive for unisolated CDI noise? Should I abandon it for this input and switch to a PC817 optocoupler instead?

Thanks!

Hello everybody,
i have an VW Beetle, aircooled, 1679ccm, KKK K14 Turbo, injection and an Megasquirt MS1 V1.01 and i wanna configure the Cold start because at this time the car only starts with Start Pilot. And without, the engine only spins and does not ignite. Also i am new to this whole Megasquirt ECU thing and i would want to ask if anyone of you can explain to me, how to configure Cold start on Tuner Studio on this Aircooled (!) Beetle.

What sensor(s) and TunerStudio settings will make the ODO & Trip work?

Tried multiple gauges, Trip / Economy settings, and output Channels in the properties dialog box with zero luck. Currently single hall-effect VSS. Speedo is accurate.

Looking for confirmation of my ignition setup: going into a 2000 Saturn SL2 with stock 4 cylinder waste spark ignition (stock OBD2 ICM wiring). The ICM utilizes 2 spark inputs (1 for each coil pack, firing order 1-3-4-2, coils fire 1&4 and 2&3) which I've wired internally as Spark B to Spare 3 and Spark A to IGN. Can provide more pictures if necessary.

Hello all,

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I've got a stable running setup on a sbf with megasquirt 2. I'm getting pretty bad economy (<10mpg) with my truck so I've been trying to lean things out where I can.

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I recently noticed that the wideband reading (Innovate LC-2) on my Innovate gauge is as much as 1.0 different (lower) than what tuner studio is reading. My nose tells me the gauge is right (rich af) but I don't want to push anything too lean.

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Anyone else have a similar experience?

I have a 99 miata with a 01 miata engine in it and i just put in a mspnp2 running tuner studio. The car turns on and runs but when the iacv is plugged in the rpms go to 2k then idle at around 1350. When i unplug the valve it drops to about 850. While it’s plugged in the Idle PWM % starts at about 50 then drops down to 31 and won’t go below that. I have the idle warmup duty table set below 31 yet I still can’t get it to lower. Any advice would help a new tuner:)

I found an Ancient MS1 and want to know what a pcb version this is. Also it says on the back: Megasquirt PCB by P. Carlier. Also if u have ANY more useful information for this please let me know

I'm probably in over my head on this but how do I get the pins in place on this serial port and how do I connect it to what each respective pin is for. Do I just find the wire it's for and splice it in? 91 na Miata 1.6

Took me forever just to figure that out lmao, but on my MSPNP2 for my 92 hardbody I have dead cylinders on 2 and 4. Didn’t happen with oe ecu, I’ve reinstalled the base tune, and firmware several times and changed every setting twice in tuning studio. Pretty sure it’s fuel related not spark but not positive, my best guess is maybe a jumper inside the unit? Bc it did it out of the box, never has ran with those 2 cyl. Idk yall know a lot more than me, so I’d be eternally grateful if yall helped a brother out 🙏

Hey all! I just spent a few hours swapping my OBD1 car over. I was tired of trying to chip tune and added the pnp.

It was an easy install, car fired up on the first try. I have a supersprint header with O2 sensor bungs on 3 cylinder (1-3, 4-6) running perfectly on CAN.

Went out to do some auto tuning and hit the dreaded crank loss at 3k RPM.

I’ll be wiring a 10k resistor in place tomorrow in parallel between the sensor wires so more to come on that.

Just so I understand the parallel- basically take the 2 wires from the MS (signal and ground), leave them connected as they are, but wire a resistor that connects the 2 wires? Like the photo but a 10k (per DIY to start).

Thanks for any help.

Looking at the BoM for Megasquirt boards, specifically the older V3 through-hole ones, is there an up-to-date list of components / alternatives?

Off the bat, the MPX4250 went out of production last year, the IRFIZ34 is long obsolete, and there's a few other devices on there that at best you'd be buying compatible versions of.

Or is everyone using newer boards with different parts now?

Im running a Microsquirt on a BMW E30.

Im losing signal from the crank sensor at a consistent RPM number.

I have tried various resistors and 3 different crank sensors (1 OEM used and 2 Brand New) so Im at a loss. I have the sensor gapped prooperly. This is a hall sensor on a 60-2 crank wheel.

No resistor cuts out at ~2000 rpm.

10K resistor cuts out at ~5500 rpm.

20K resistor cuts out at ~4000 rpm.

Any ideas?

how do I go about fixing the AFR? the ECU is a kdfi 1.4a with bosch ev 14 731cc injectors, a rep 3576 on a m50 block with m52 bolt-ons.