Fuel Meter Problems

[that70sboat]

I have twin 4 stroke 150s with the two inline fuel flow senders that have worked pretty well up till now. I'm still getting readings on fuel Flow and total fuel used as well as the Fuel economy but seems like Its only picking up from one of the senders. Is the quickest way to diagnose the problem to unplug one at a time to see which is sending info. And if so, whats the next best step to repair after I figure out which one is not operating correctly?
Thanks in Advance.
Dave

[FabricGATOR]

I'm looking at this because I have a similar situation with mine. I pretty much figured it down to the stbd motor by shutting down (or just idle in neutral) one or the other engine, then running her up a bit to see what one changed the flow value.

Background, I have twin 2000 150's the ox66 two stroker's. But I imagine that the technology is the same or similar. What year is yours?

So for the next step, I am going to swap plugs at the sending units and do similar tests to see if the other motor begins to operate the 1/2 flow. If it does follow the plug, I will know it is the wiring for that circuit. If on the other hand the same motor changes the fuel flow and the other does not, I will suspect the sending unit.

We use similar flowscan transducers in aviation and swapping parts from left to right is common practice to see if the fault follows the suspected component.

Now another thing I have become aware of is that if you push the set button while in operation, there should be a P, S, and PS indication on the gauge that tells you if you are looking at Port flow, Stbd flow, or PS would be both.

My gauge does not seem to do this but I do see the P and S displayed while the gauge is self testing at boot up, when I first turn on the key. I have not found how the gauge knows if you are running twins and if there is a setting somewhere. Possibly, it will sense that there are two transducers attached and then boot up into TWIN mode. So quite possible, I may simply have a bad connection and thus the gauge boots up in single engine mode because it does not see the two motors.

We will get through this.... hopefully someone will give us the answers.

[that70sboat]

Yep,
Same issue I'm having. I'm going to try what you are doing this weekend as well. I was hopeful it was something simple and just cleaned my plugs at the sender side of the harnesses but it didn't do anything. Process of elimination I I guess? Need to get to know it better anyway as I'd really like to hook it up to my gps in NMEA 2000 possible.
Good Luck and let me know if something works for you and I'll do the same.

[FabricGATOR]

Hey Dave,

I was all excited because I saw someone had replied and was hoping that they were expert advice about xshooting our fault....

I hope one of the resident guru's helps out and offers their wisdom and extensive experience.