Flyback driver module installed

[BlackBird_SR71]

Helping remote Tune an MS-2 version 3.0 for a young fella halfway across the Continent.

He has low impedance injectors but has removed the factory dropping resistors ( Datsun 280ZX Turbo ) Has been having terrible fueling issues. He built the board himself, but is not sure if it has a Flyback board for the injectors. Injectors were checked with an Ohm meter and confirmed as Low impedanceI have a picture of his board:

1: Can any one tell from this picture if he has the Flyback board installed?

2: He has been running the car and actually able to drive it... although it doesn't run very well. ( There are some fuel plumbing and pressure issues as well ) If the board does not have a Flyback Driver Module and no dropping resistors, can anything be damaged. Tuner Studio was originally set to run with No injector PWM. Then I found he had no dropping resistors, so I changed the settings to use PWM Current Limiting for Low impedance injectors ( .msg attached ) . Now he's not sure if board has Flyback Driver module. So I'm rather concerned. Btw, PWM Current limiting being Enabled did not flag any errors. Don't know if it would if Flyback INJ Driver board was not installed.

He is a young fellow and is trying very hard to learn. But he's in a little over his head. Getting issues sorted one at a time. Still lots more to correct on Hardware fueling side, but right now I'm concerned if the board may have been damaged:

Richard 260cc Tune 4.msq

Richard 260cc Tune 4.msq

[BlackBird_SR71]

I think I may have found my own answer. After digging through the hardware manuals, it looks like the MS-2 version 3.0 boards come with the PWM Current Limitings drivers built in. Is that correct. The Flyback Module addition was added to V2.X boards??

Question still remains if he has damaged the board by running the Low impedance injectors with PWM current limiting turned off ( previous tuning ). Your thoughts.

[slow_hemi6]

DIY Autotune has a walkthrough to test the injector outputs. If everything checks out, it is unlikely to be damaged. https://www.diyautotune.com/support/tec ... or-driver/

[DaveEFI]

The injector drivers - if fully built, which yours look to be - have current limiting. So hopefully will have survived.
Follow the section in the manual on how to set the PWM.

[prof315]

In general if the injectors still fire nothing has been damaged YET, but continued use of low Zs without PWM will break things eventually.

[DaveEFI]

In general if the injectors still fire nothing has been damaged YET, but continued use of low Zs without PWM will break things eventually.

Depending on how many injectors per bank, you might also burn out the injectors themselves. They can't handle neat 12 volts.

[BlackBird_SR71]

The injector drivers - if fully built, which yours look to be - have current limiting. So hopefully will have survived.
Follow the section in the manual on how to set the PWM.

Thanks all. The board is not my. I'm just helping tune remotely from 2,500 miles away. Picture is from the fellow that built the board and is of his board. I've got it running on the recommended PWM settings now. But before I got involved it was not running any current limiting. It runs and drives so hopefully the injectors aren't damaged.

'Still battling some excessively rich mixtures, but that is in part due to excessive fuel pressure at idle and possibly the dead time for injectors too low. I can get it to idle nicely, but VE table figures are in single digits. Gonna increase injector dead time. Injectors are " supposedly " Datsun 280ZX Turbo injectors. Low-z 260cc.

Pulse width down to 1.3ms which seems correct, but VE cells in that range in single digits as mentioned. Had set idle by MAP pressure and Vaccum gauge ( Old school ) because LC-2 O2 sensor is hooped. Mounted too close to Turbo and fuel contaminated. Don't trust the AFR's it's showing. Got idle vacuum to maximum of 19.0 in/hg and went all the way over the top of the Bell curve for Rich Best idle and Lean Best idle as per Vacuum gauge.

[prof315]

Dead time is too high not too low if you are in the single digits at idle. Dead time's effect on fuel flow is counter intuitive.