ms3x sequential added, now super lean

[Masterofmachines]

I just installed the DIYautotune trigger disc in my l28et and got everything set up for sequential. I was driving my injectors off the main board in a "batch fire" configuration previously and had a pretty solid tune on it. After wiring injectors to the ms3x board engine is extremely lean at idle on the same VE map as before. I had to bump up VE to 90% to make it idle at a happy AFR! What could cause this to be so different? Is it possible that the injectors are firing out of sequence? Engine seems smooth once I added enough fuel, & I have confirmed my base timing is correct. tuner studio shows "full rpm sync" and there is no "cam fault" icon illuminated.

[ZHoob2004]

Just guessing because I'm not very adept at tuning, but I believe this may have something to do with your injector dead time, IE the amount of time it takes for your injectors to open when a voltage is applied. I understand one way to tune this is to switch back and forth between sequential and simultaneous injection and adjust until your AFR is the same in both modes.

[HuD 91gt]

Inaccurate dead time could certainly have an effect.  We’re you running 2 squirts per cycle previously?  Try a similar setting while sequential.

 

 

First things first are to check everything is firing in the right order as you suggested though. Very easy to check with Megasquirts test functions.

Edited January 14, 2020 by HuD 91gt

[Masterofmachines]

On 1/14/2020 at 9:54 AM, HuD 91gt said:

Inaccurate dead time could certainly have an effect.  We’re you running 2 squirts per cycle previously?  Try a similar setting while sequential.

 

 

First things first are to check everything is firing in the right order as you suggested though. Very easy to check with Megasquirts test functions.

I upped my dead times and that seemed to help a lot. I’m still finding odd stuff though. For example, I had to jack up my cranking fuel significantly to get the car to start well, like 80%. I probably need to adjust DT’s more. Just seems unusual that I’d have to change so much of the tune just to go sequential with all the same components.