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NEMA 2000 adaptibility to TBI using Diagnostic Port

Fallflight

New member
Hello All,

New to the site, so be easy on me

I have an older boat with a 350 Chevy (Mercuriser) that I converted to Throttle Body Injection using guts from a 1993 Chevy Truck (CG approved). The boat has a diagnostic port (OBD2) that gives real time data that I can view on my Laptop. All engine EFI is controlled by the truck Engine Control Module.

Is there any way to adapt this active info via the diagnostic port to NEMA 2000 so I can use the dashboard on my new Humminbird Helix 7?


I am at a total loss on this issue and any help would be appreciated.

Thanks,

Fallflight
 
You can get the senders and add them to the engine and just run them to a NMEA 2000 loop. water temp, oil pressure, fuel pressure, oil temp, fuel flow ect. Research NMEA 2000 analog conversion it can be done might take some work tho and parts aint cheap. Others here will know alot better what your options are. Is the engine computer NMEA 2000 complient?
 
Thanks for your rely

No, the electronics are off an older Chevy Truck, a 1993 Throttle body. I was able to gut a truck and move all engine electronics to the boat, reprogram the ECM and remap the fuel delivery. runs excellent compared to the carburetor that was on it.

I dont really want to put individual sensors as all the engine data is already available through the diagnostic port. I just need to get the NEMA equipment to talk to this available data, IF THIS IS POSSIBLE at all.

-Fallflight
 
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The senders are all analog water temp, oil pressure, fuel level, RPM? I am sure the wizards here should be able to point you in the right direction like I said research analog to NMEA 2000 conversion you may need to eliminate the dash guages to hook up the NMEA senders they must be NMEA compliant. The dash guages are independent of the computer except engine temp for the computer should have a 2 wire sending unit. The temp guage has a 1 wire sender. If you have a return fuel line to the tank you will need two fuel flow sensers. I remember reading a thread a while back maybe you can find the info here using the search feature?
 
you are correct. All the current gauges are analog. Nothing on the dashboard comes from the computer (I did put a check engine light) I put a separate temp sender into the intake for the computer so that all the previous gauges could be used. Yes, you are also right, both the Analog temp and Oil pressure are 1 wire.

So, The computer currently gives Tach, water Temp, timing, O2 sensor, MAP, TPS and System Voltage through ALDL or Diagostic port. Oil pressure and Fuel level and boat speed are still analog.

All Analog gauges still work at this point
 
Boat speed is normally run from water pressure pitot on the transom and is strictly mechanical, Does your hummingbird have GPS? I imagine the right transducer will give you water temp and boat speed as well just guessing tho. What is the complete model of your hummingbird?
 
Helix 7 Chirp SI N is the model, it does have water temp and GPS. The N on the end of p/n is for Networking which is basically the NMEA 2000

When I referred to water temp earlier, I was referring to Engine coolant temp.

There is an analog to NMEA 2K called the Alba Combi that looks like it would be perfect for my application. IT looks an aweful like a PLC I was given as a gift. See attached. The only problem is that I dont know how to use it!!! Ha Ha. Maybe I can save $400 using what I already have.

-Fallflight
 
So will these analog converters alter the data, in other words, can I still have the analog gauges working while converting it to something that the NMEA can use as well? Can both analog and digital work at the same time?

Thanks!

-Fallflight
 
There are different types of senders for dual station or single station or european values. I dont believe it will effect the operation of the guages but I believe you program the fish finder for the proper type sender it is reading IDK for sure tho. That will give me something to do its hell being unemployed.
 
It does not effect the operation of the guages. The user guide shows you how to wire it and the programming tool will change the parameters depending on what type guages and tach signal. You can also add fuel flow senser/s. If you have a return line to the tank you need two sensers and it calculates fuel usage. The AlbaCombi you connect your laptop to the converter via ethernet cable and go to the website and program it from there. The converter just uses your fish finder screen as the dashboard is my guess.
 
I'd say it could be done but is going to take some effort....your existing ECU uses the GM proprietary 'network interface' where the NEMA 2000 is more 'modern'.....now, if you had a CANBus based ECU, then I'd say "its only software".....

If you have the time and have access to the DELPHI design data, it may be easier to program your existing ECU to provide a NEMA compatible data stream of what it has already "read".....Or, if you have a 'smart' NEMA 2000 device, you could program it to inquire with the ECU for the various parameters you want displayed.....
 
thanks Makomark!

You have my attention. Ultimately this is what I would like to do, but I have no Idea as to how to get it running. I only know that the data is there, in some form. any additonal help is appreciated. Analog would be the next option.

I will look into CANBus,

Regards,

Fallflight
 
What I'd envision is a black box - call in an interpreter - with two interfaces. One for the CANBus (NEMA2K) and one for the existing ECU. Once it was started, it would enter a loop where it would request the desired parameters from the ECU and then buffer them. Once the buffer is full, it would then provide those data to the NEMA side, according to the needs of the network you have there.

It could be a simple a PIC controller or a lavish as a laptop. the difficult part (i expect) would be to find a viable chunk of source code (drivers) to start with....you could always start from scratch, depending upon the 'tools' available and your experience....

just my two cents....
 
After doing a quick study, I think that this can be a done with an Arduino board? I will do further research, but I think so. IF you know different, let me know and I will cease research.

Thanks,

Fallflight
 
Not familiar with that board.....I'm sure there are MANY options....

How did you eliminate the current ECU's need to see the O2 sensors' outputs?
 
There are adaptors you plug into the OBD2 port and you can monitor engine performance with blue tooth. Keep us posted on your progress I am sure others may benefit on your conversion to TBI and linking it to a NMEA 2000 bridge.
 
makomark......I did not eliminate the ECMs need for the O2 sensor data, I bought a fitting to tap through the water jacket, just need to use a bridgeport to mill the exhaust manifold and the o2 sensor fit right in. ECM uses o2 sensor data in closed loop
 
Just wondering what distributor your running with that. Does it have the mechanical advance with the marine curve? Did you do a wright up on the conversion?
 
I used the GM 93 Truck distributor that works with the ECM from same year, this way I could tune the spark advance based on load, but generally following the stock curve program. It even has a spark arrestor!



I didnt do a write up on it, took me some time to figure out how to tune it using Tunerpro XT

I love the way the engine runs. much better than a carburator. its all CG approved too.

I would be happy to share the TON of things I learned while doing the TBI fuel injection project from a carburetor, as I didnt know much before I started.

1) I started by going to a junk yard and for about $100, I gutted all the vital engine electronics from a 1993 Chevy truck, ECM, Throttle Body, MAP sensor, Distributor, coolant and Knock Sensor, ETC

2)I worked with the guys at HOWELL Engine development in Marine City Michigan who helped me a TON, they made the wire harness for me. They also helped me program to flash and reprogram the chip for the ECM. (They make TBI units aftermarket, but had little experience with a marine application. Generally the same thing though.

3) I got familiar with the TUNERPRO XT software and was able to map the fuel using an Emulator real time while out in the water and would Datalog the engine performance. This way I could bypass the programmed chip and make changes as needed. I used a Moates Ostrich 2.0 emulator.

4) In Tunerpro, you can shut off / bypass all the transmission inputs that are used in the vehicle as they affect performance.

5) Once I had the engine running perfect, I then had the factory chip reflashed with the program that was running it in the emulator and put it into the ECM.

6) As an insurance plan, I put a stoichiometric Air / Fuel gauge in the dash that I can monitor in Real Time.

I love it!

-Fallflight
 
I havent researched any further, but to spend another $400 for an analog converter?

I like the Arduino approach, but still need to look into it a little further. It may work
 
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