Hello.
I have been trouble shooting this for 3 or 4 years now. Dyno shops don’t want to help because it’s not a Holley ecu.
Car runs great on 1 to 12 lbs of boost as long as you don’t rev beyond 5000 rpm.
I have posted before of problems ,change things and try again sometimes it takes months to do.
Here’s the setup
70 chevelle 383 sbc, twin Garrett 3882r, small solid roller with spring pressure at about 300lbs on seat and 590 at lift. Dart 2 cast sportsman heads.
Megasquirt 3 ultimate, Holley smart coils near plugs, msd flying magnet crank sensor and msd cam sync sensor.
Dual in tank Holley fuel pumps to semins 83lb low imp. injectors.
The engine just hits a wall and sounds like a 2step or rev limiter can be very violent sounding. There are no signs in the logs of anything wrong just that I lift when I hear it. No faulty cam sync detected. I just had the injectors cleaned and good fuel pressure at regulator. I’m using a r type plug but there aren’t a lot of plugs to choose from for my heads.
This motor should rev to 7000.
Please help.I live in CT if anyone is near.

thanks Brendan

 

I will add files just don’t have them on my phone.

 

Here is the MS3 file.

Trying to upload a log file but having trouble. Don’t remember how to do it.

 

Have you ever revved it through all the rpm range with a timing light on it and verified its doing what the ecu says to do.
Even connect compressed air to the map and simulate boost conditions.

It could have hysteresis or pickup parameters incorrect.

 

So I'm really curious what's causing your issue. I looked through your tune (as a novice so take that for what it is) and saw nothing that stood out. Normal rev limiter settings with no boost cut or CLT based limits that should lower your rev limiter.

I read your other thread too. Nothing to add there other than constantly adjusting the valves seems odd.

I think posting a log and a video would be very helpful. Especially if it sounds funny.

 

Low impedance injectors are pretty uncommon these days. I believe they require some additional configuration on the megasquirt. Have you accounted for this?

 

What does it feel like? You're just hitting a wall out of no where? Have you pulled plugs to sanity check your WB?

Looking at the tune, it says that 4A/1A is recommended for high-z injectors. I'm not familiar with MS3 but I'm wondering if that needs looked into. This is significantly different than the MS2 stuff.

Have you checked your ignition/dwell yet? Your spark duration is set to 4mS and with individual coils it may well be right, but its help says 1MS typical. Also, check and feel your coils to see if they get hot. Don't forget an ignition problem and fueling problem may look similar.

I will also say that I never had much luck using TBI Injectors with a Megasquirt. I'm sure some have but I wasn't one of them.

This may well be kind of a strange question, but you did measure the push rod length correct? I had strange aberrations at higher RPM when I didn't have the right length on my 383.