Need some help with a boat motor

[Solly]

Complete newb here.
I have a boat with a 350 SBC inboard set up with a stock GM TBI. Running a V2.2 board with a MS II chip and with V2.92 code.
Motor starts fine, IAC works and idles down OK. Battery voltage will flash red. However about 3000 rpm the motor will run out of power, spit and sputter, and shut off. Also the accel enrichment comes on. I did install the flyback components after toasting the ones on the board.

Attached is the current tune.
It says the log file is to big ?? How can I post the log ??

Looking at the log I see the voltage dropping pretty regularly. That's the only thing I see unusual. Voltage is steady with the stim.
At 3000 rpm all the readings go crazy, engine will shut off.

Attached a couple pics of the log file, maybe it'll help.

Anyway check out the tune and see if anything is set wrong.
I'm thinking I'll work on getting the voltage steady first.
Any other ideas ??
Thanks a bunch !!

[kholman]

It says the log file is to big ?? How can I post the log ??

Max attachment file size is 1.25 MBytes. If you can trim the log below that, it should attach.

[Matt Cramer]

Or you can stuff the log in a ZIP file - they compress pretty well.

[Solly]

All right !

Log is attached as a .rar file.

Should mention the log starts out with the motor at idle warming up. Then low rpm out of the anchorage.
Up'd the rpm to about 2000 to cruise and then 3000.

Crazy stuff starts at about 1500 sec and motor finally dies at about 3599 sec.

Being a boat I don't push the rpm's, seldom wide open.
Just looking for a reliable running engine. Cruise will be between 2000-3000 rpm probably.

Thanks,
Solly

[Ranchero50]

Hey guys, another new member popping in, actually Solly's son, Jamie. Here's some pics of the engine and how we mounted the controls in the cabin to be accessible. I'm a former Navy ET and did the wiring using marine specs with soldered connections etc. to minimize vibration and other problems.

The MS has it's own power feed and fuse block that feeds the fuel pump, MS and a Chinese knock off HEI (MS would not fire off the original 7 wire TBI dizzy). Other than a shared tach signal and the command wiring to the relay the MS is isolated from the hull wiring with the exception of 12 ga feed and ground wires. It uses two relays, one to power the MS and HEI and the other for the fuel pump.

Pre fly back board we popped the injector fuse around 3k and some of the components on the MB keeping the injectors open all the time. After the fly back board install we really had to tweak the basic settings to get the MS to fuel a decent AFR at full load. It then had some low RPM drive ability problems so dad loaded a earlier tune to get decent low RPM performance.





One of the worst things with the boat is it's 3 hours from home in the water. We'll trailer it home at the end of the season but it's hard to load test stuff out of the water. It's a 1984 28' Chris Craft Catalina



Hope this makes some sense and isn't totally confusing.
Jamie

[trakkies]

I have a V3 board driving 4 low impedance injectors per output directly (no resistors) using PWM, which has been 100% reliable. The V3 outputs were designed with this sort of thing in mind.
As regards either an injector or ignition output grounding when the engine is stopped, one answer is to feed them via a relay which is switched from the pump relay, which only makes when the engine is turning.

[Matt Cramer]

You have noise causing the AE to false trigger at 2600 RPM, making the fueling a bit random there. Try raising the TPSdot and MAPdot thresholds.

Also, a wideband O2 sensor will be a big help with fuel tuning.