Hello! I'm new here from a referral over on THT forum and looking for some help. The shops in this area are all swamped and booking 6-8 weeks out for technician time, hopefully this is something that I can fix myself!
...
I have "new to me" twin 2001 optimax 225 outboards, everything worked prior to the take off from a 28' whaler, now installed on a '88 northcoast 24. Here's the issue that I need help on, the left/port side tach gauge is not getting signal from the engine. There is a "Engine Data Bus" error on the screen.
See page 37 of the install manual, I have "Non-can" style installation. The only variation that I see is that both gauges are run off of one battery (PORT); theoretically this would only cause an issue with the starboard gauge...?
<See Announcements>
I saw online to check the ohm between the "blue" and "white" wire at the gauge and that it should be approx 60, if 120 its a resistor issue. The ohm reading was 122. Where is the resistor though and how do I change it?
Thanks in advance!!
PS I also have this harness (see photo) that came with the boat that I believe is used for fuel/oil connections. Where does it plug in (at the helm or outboard?)
Last edited by EuropeanAM; 05-11-2021 at 12:50 PM.
Reason: Announcements- Copyrights
If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!
What you have are the old SMART Tach and Speed Gauges (word "Smart" used loosely, of course). References to the blue and white Can-P wires in other documents don't apply here as this is a "Pre-Can Trunk" system.
First and most importantly: Did these instruments BOTH function in the previous boat?
Pictured is the Fuel/Oil/Paddle harness in your boat. It plugs into the engine (normally the STB engine) via a 6-pin harness labeled "Smartcraft" that often is laying in the bottom of the cowling. You MAY require an adapter to plug it in, depending on what engine was on that boat previously.
Did you transfer the ENTIRE wiring harness setup with those engines?
Each engine have it's own SEPARATE cranking battery?
A Common GROUND Battery Cable is tied between the two Engine Cranking Batteries?
Thank you! Serial numbers are 0T336202 & 0T344777.
1) Yes, these functioned on the old boat (Whaler that go repowered)
2) Thank you RE adapter. This was installed on the last boat...I'll locate the 6-pin at the engine, I think I saw it when hooking up shift/throttle cables.
3) ...Yes, I have installed everything that came out of the old boat EXCEPT the oil/fuel harness (note 2)
4) Yes, I have 2 engines and 2 shutoff switches. The helm and house panel is connected STARBOARD battery (having issues with PORT gauge)
5) They share a common ground (black wire connected together)
Connections all checkout in terms of being visually/physically good. This is the one large harness plug with 3 single wires at the engine and then several plugs up at the helm/keyswitch area. Is there a way to test resistance/voltage to verify these connections electrically?
I try swapping the gauges...both read "Engine Data Bus" when connected to the Port engine. OT344777 is confirmed on the port side also. I'm unsure of which gauge was on which side originally (but both share the error code).
The connections all seem free from corrosion (they have a bit of dielectric grease on them). I might try some electrical contact cleaner to see if the grease is creating issues(?)
Also, some more info: on the *working* starboard side, the tach gauge moves briefly with the keyswitch, then takes 2-3 seconds after engine is started to display RPMs (assume that's normal). On the NON working port side, the tach gauge ALSO moves briefly (jumps 1/2 inch) with the keystitch, but instead of displaying the RPM after a few seconds, it displays "Engine Data Bus" error.
Might simply try swapping those plugs just to be sure. In "most" cases the Speedo was on the STB side (noticed it's dead too which is what makes me wonder).
OK...checked a whole bunch of things tonight.
1) Swapping tach plugs = same result, the tach plugged into the port engine shows "engine data bus"
2) Checked the connections at the engine. Here's the thing, when this 9-pin plug is plugged in with key switch on, there is a definite connection made bc you can hear the fuel pump kick on briefly.
3) There is a solid brown wire connected at the engine but NOT at the key switch. What does this do?
4) Both tachs ARE calibrated correctly port/starboard.
5) There is a purple "jumper" style wire zip-tied to the harness at the key switch but nothing apparently to connect it to. What does this do?
6) The speedo is connected to the STARBOARD engine.
Here are the photos, this is too many to upload here... https://photos.app.goo.gl/VfCB5411D1a6C1vS6
*note, some things in the pics are not connected. Unless noted above, they were disconnected & replugged in for the photo op only...
Here’s the deal, I took the STARBOARD harness and plugged it into the PORT engine. In that process, I noticed that the ST harness had 4 wires in addition to the 8 pin, whereas the PT harness had 3 wires in addition to the 8 pin. I dug around and found that Whoever removed the old harness on the takeoff process broke the brown wire right at the 8 pin. Anyone know how to remove the end of a harness to reconnect this wire?
I will upload photos from my computer in a little while.
That brown w/white stripe wire was originally Analog Trim. However... as I recall, the "Pre-Can" data was traveling that wire.
The black connector cannot be safely removed from the harness as it's a molded-in part. Being as your options are quite limited (ie: Replace harness), you could open the sheath carefully and see if you could extract that one wire and connect it with a sealed bullet connector (one example).
Twin Optimax 225 "Engine Data Bus" Error
Reply With Quote
