- Thu Oct 20, 2022 3:24 pm
#59009
I have a 2005 Mastercraft X-Star with a Indmar MCX350 (Basically a fuel injected, distributor ignition, drive by wire 350 Chev). The boat has had a tough life living in the salty waters of the Persian Gulf and has numerous engine harness and ECU faults. The engine, gearbox and hull are in good condition so I would like to breathe life back into the boat with a Speeduino.
Over the last few weeks I’ve been researching the forum, reading the manual and following build posts from other members. In particular Dstage’s posts about drive by wire and Apollard’s Speeduino boat build posts have been really useful to me. I’m a relative newbie to open source ECUs but I think I’m ready to buy the required components and get started.
Before I take the plunge I’m hoping that someone can have a look at my assumptions to see if I’ve missed anything obvious or not so obvious.
Speeduino
I plan to build or buy a Speedy without the built in MAP sensor. Is it possible to get a Speedy built through a service such as JLPCB and then make a financial contribution to the community or is it better to buy directly with one of the three recommended stores?
DStage DBW board
I’m assuming that this is the current best solution to the DBW issue?
Is the only option to purchase this board from JLPCB?
GM 8 Pin Conditioner
Is it best to go down this route or to hook up to the existing crank angle sensor?
TPS
It seems that my TPS is a 6 pin. Will this work for the project or will I need to find an alternative. The link to the TPS is here.
MAP (Manifold Pressure)
I plan to use the stock MAP on the boat.
Temperature Sensors (CLT and IAT)
I guess the stock sensor will be fine here too?
Exhaust Gas Oxygen Sensors (O2 and WBO2)
I plan to purchase this wideband O2 sensor and mount it at the exhaust manifold elbow.
Injectors
Need to check the impedance, once again stock.
Coils
The coil I have is a standard GM coil
Aux Outputs
Is it better to control the fuel pump with a relay or a HC MOSFET?
Auxilary IO
I would like to add a fuel pressure input in the future.
I would also like to add a bluetooth module in the future.
I’ve mapped out the basic build diagram at the link here.
I’ve also created a spreadsheet with approximate costs for the project.
It’s been great to read the Speeduino documentation and to learn from builds of other community members. I plan to document my own process so that others can learn from my mistakes. Hopefully my assumptions are in order so far and there are no deal breakers in this project. Thanks again to anyone who comments on my plans so far, I’m excited to get going!!
Over the last few weeks I’ve been researching the forum, reading the manual and following build posts from other members. In particular Dstage’s posts about drive by wire and Apollard’s Speeduino boat build posts have been really useful to me. I’m a relative newbie to open source ECUs but I think I’m ready to buy the required components and get started.
Before I take the plunge I’m hoping that someone can have a look at my assumptions to see if I’ve missed anything obvious or not so obvious.

Speeduino
I plan to build or buy a Speedy without the built in MAP sensor. Is it possible to get a Speedy built through a service such as JLPCB and then make a financial contribution to the community or is it better to buy directly with one of the three recommended stores?
DStage DBW board
I’m assuming that this is the current best solution to the DBW issue?
Is the only option to purchase this board from JLPCB?
GM 8 Pin Conditioner
Is it best to go down this route or to hook up to the existing crank angle sensor?
TPS
It seems that my TPS is a 6 pin. Will this work for the project or will I need to find an alternative. The link to the TPS is here.
MAP (Manifold Pressure)
I plan to use the stock MAP on the boat.
Temperature Sensors (CLT and IAT)
I guess the stock sensor will be fine here too?
Exhaust Gas Oxygen Sensors (O2 and WBO2)
I plan to purchase this wideband O2 sensor and mount it at the exhaust manifold elbow.
Injectors
Need to check the impedance, once again stock.
Coils
The coil I have is a standard GM coil
Aux Outputs
Is it better to control the fuel pump with a relay or a HC MOSFET?
Auxilary IO
I would like to add a fuel pressure input in the future.
I would also like to add a bluetooth module in the future.
I’ve mapped out the basic build diagram at the link here.
I’ve also created a spreadsheet with approximate costs for the project.
It’s been great to read the Speeduino documentation and to learn from builds of other community members. I plan to document my own process so that others can learn from my mistakes. Hopefully my assumptions are in order so far and there are no deal breakers in this project. Thanks again to anyone who comments on my plans so far, I’m excited to get going!!