Megasquirt Help Please

1982 Datsun 280zx, NA to T conversion, MS-Extra 029y4, v3.0 board, VR from locked distributor, AEM wideband. I am running magnecor wires to cut down on noise, and also a colder thermostat and plugs to cut down on pinging under high loads. I am limiting boost to 5psi or so. The VR lines are shielded coaxial.

I noticed my battery voltage fluctuates but don't know what this means. Occasionally - rarely - I get resets where the car stumbles hard for a split second and then comes back to life. I suspect these are related.

The car stumbles a bit when running and I try to accelerate quickly. Sometimes she pulls like a freight train, like an on-ramp rowing through 1-2-3. But, if the car is already moving at a good speed, if I hit the throttle or downshift and hit it, it bogs for a bit. I think my acceleration enrichment needs tuning, but I'm not sure. TunerStudio autotune did a great job already on my maps.

Lastly, I have hot restart issues. I have to open the throttle a lot to get it to start when its hot. I have no idea what's wrong here, but maybe some heat soak going on too.

I have a MSQ and Logs here if anybody is so inclined to look: http://z.modeltrainguide.com/msq/

Thank you for any tips or advice! Maybe I should post my maps as JPG's too?

Have you checked rotor phasing? Best to sacrifice a distributor cap and cut a window in the side so you can see the terminal and set timing to 25° fixed then work on dist to get rotor centered on post (at 25°)

Have you followed the recommended grounding? section 3.2. Battery grounds, power sourced through the dash harness?

Is your fuel pressure regulator boost referenced?

Have you checked your injectors for leakage?

Location of IAT sensor? Cold side of intercooler is the best place away from radiator.

High or Low impedance injectors?

Why have you not updated your firmware? 3.4.x is the current stable

Hot restart: work on your MAT correction. "Out of the box" it's waaaayyyyyy too aggressive.

Accel enrichment: this isnt autotuned, so you'll need to work on it. DIY Autotune has a great video on youtube on tuning this.

Thanks everyone! Here's my answers.

Rotor phasing - I haven't checked that closely. I have checked timing with a light; that's it.

Grouding - yes, I adhered to the installation instructions in the megamanual.

Boost referenced FPR - I believe so, its connected to a vacuum line on the intake manifold, after the throttle body. I could move it before the throttle body, why is that better?

Fuel injector leakage - no, and I probably should have them cleaned. Maybe I'll send them out this winter.

IAT sensor is in the center of the j-pipe. I'm not running an intercooler, its still in the planning stage! Its an open-element GM sensor I grabbed at the junkyard.

Low impedance, stock 280zxt injectors. 260cc/min I think?

Firmware: 029y4a is the latest MS-Extra for MS1 processors. I am running 029y4. Need to see what they changed for "A".

MAT Correction: I'm a dunce, I can't find this in TunerStudio. I don't remember setting it up either. There's a "coolant corrected air density", is that it?

Acceleration enrichment: thanks, I'll check the video.

Here are my maps:

Oof. I dont know much about that motor, but that's a LOT of timing, and your target AFRs in boost are waaaayyyy too lean. Your stutter/misfire could very well be detonation.

On your hot start log, the pulse width is zero for the whole log. What's up with that? Also on your driving log the battery voltage is all over the place, min of 7.4 volts, max of 17.3 volts, some serious electrical noise. Fix that any several other things may get better. For the AE, I would lower the TPSdot threshold as low as you can go without AE triggering on electrical noise, it's kind of high at .97 v/sec I don't know how your O2 reads but I am guessing higher voltage means leaner. You notice that your PW and MAP track together almost exactly, even when you open the throttle, that means no extra PW from the AE, and the O2 goes up when you open the throttle so I guess that means leaner.

Lean the VE table in the 500 rpm column, from 100 kpa to about 60 kpa to get the hot start better. Crank the engine and watch what cells it uses to get the hot start right, then use the warmup wizard to get it start cold.

I don't think the MS1 has MAT Correction

^ Hmm, you're right. MS doesn't seem to think the engine is cranking. Zero pulsewidth means flood clear mode?

Any tips on fixing the electrical noise? I read about putting a 0.1uF cap on the boot header - does anyone know if this is for MS2 only?

I'll richen the target AFRs and let autotune do its thing, and see what happens tomorrow.

Could be in flood clear mode, but the TPS in the log doesn't show the TPS being high.

The electrical noise is coming into the MS via the power feed, what else is on the circuit that feeds the MS? Ideally nothing else. Maybe you should try powering the MS from a relay directly from the battery, where the relay is controlled by the ignition switch.

I think the boot header cap keeps radiated noise out of the boot header, I don't think that's you problem.

You've got to get the voltage issue stabilized. I presume MS has a table for injector dead time? If you're operating outside of that range, then you can definitely expect to see some issues with your injectors getting the right fuel delivered.

Rewiring to put the MS box on its own relay seems to have made no difference. I ran a separate wire from the battery for it. Previously, it was on the main relay with the injectors. Next step - I think I'll try a noise filter. Advance didn't have any idea what I was even talking about. I'll have to try Autozone or Best Buy. Thanks for the continued tips.

Log with new relay: http://z.modeltrainguide.com/msq/rewire.msl

The cap across the boot header will help with the battery v fluctuation

Low z injectors, resistor box or trying pwm in the ms? Either way post the pwm settings. Also if trying to use pwm make sure the high current flyback parts are installed.

Low-Z injectors.

Here's a new MSQ and log trying to richen things up and bring on AE sooner. http://z.modeltrainguide.com/msq/rewire_ae_richen_2015-09-08_07.58.09.msq http://z.modeltrainguide.com/msq/rewire_ae_richen_2015-09-08_07.58.29.msl

Is all of this moot until I fix the noise problem?

What's the difference between putting a .1uF cap across boot H1 and 47uF 50V cap across the center legs of Q3 and Q9? Do I need to do both, or just one? I'm on MS-1; is this still applicable?

Update: I found both a 33uF 50v electrolytic, and a 10uF one. I'll put them in parallel and the C's should add to 43uF. Pretty close to 47uF. Will let you all know what happens.

I still don't see any AE in the log. Are you running resistors for your low-z injectors, or limiting current with the MS?

Do you have access to an oscilloscope?

Looks like you have pwm enabled, if you have a resistor box, turn if off (set to 100%)