Precision Blend oil indicator problem

[lrreicks]

I have a 1989 ProV 150 on which the oil level lamps are not working properly.

Upon turning the key to the on position, the red oil indicator flashes four times, a 0 is displayed on the RPM gauge and one bar is illuminated on the tilt indicator during the test period. It then changes to the yellow oil indicator with the RPM and tilt indicators remaining as they were.

The remote oil tank is full and after running tests based on the information in this forum, I've found the following:

1. Although the yellow indicator is lit, oil will transfer from the remote oil tank to the engine oil tank at key on and as called for by the engine tank switches.

2. Jumping the black and black/red wires at the remote oil tank does not change the yellow indicator to green.

3. There is continuity between the black/red wire at the remote oil tank and the green to green/white connector at the tachometer.

4. There is continuity between the black wire at the remote oil tank and the negative terminal of the battery.

5. If I disconnect the green, green/red harness from the engine from the green/white, green/red connector on the tach, when the key is turned on, all three oil indicators light, 88 is displayed on the RPM gauge and all trim bars light during the test period (I think this is the normal test period indication). The display then changes to the same indication: yellow, 0 RPM, one trim bar.

6. If I jump the green/red wire on the tach to ground, the red indicator lights. It's my understanding that this is the correct behavior.

7. If I jump the green/white wire on the tach to ground, nothing changes (the yellow indicator remains lit). I believe the green indicator is supposed to light.

I think I've conducted all the tests relevant to this problem and the precision blend system. I'd greatly appreciate any advice.

[lrreicks]

I still haven't resolved the problem in the following post. By bumping it up, I'm hoping someone who can provide advice may see it.

[Finisher]

Sometimes the tach harness goes bad and gives those problems. It can be a real pain. I had a known good oil tank known good sender new wire and i still had the yellow light. Changed the tach harness and fixed it. Good luck

[boats.net]

Need to check harness between remote oil tank and engine, all test you did were at the oil tank could have a open in wire between engine and oil tank. The 89 has an oil control module below engine oil tank and may could be bad as well. But if everything works normal except for indicator light then probably wiring problem to remote or to tach.

[florida_1959]

I had that exact same problem. Mine ended up being a break in the ground wire (black) that was running from the remote oil tank in the bilge to the engine wiring harness that hooks to the oil tank on the side of the engine. Nearly drove me crazy because it would come and go as the engine turned left or right or tilted. replace the wiring harness between the two and back to "green" on the gauge.

[neverenoughx2]

I am having a similar problem. If you still see this post can anyone give me the part number for the wiring harness. or the exact description of the part.

Thanks

[lrreicks]

Yamaha Precision Blend oil indicator problem - Resolved

It's been awhile since I've had time to work on this, but I finally traced the issue to a bad tach gauge. I bought a replacement on eBay, swapped the internal components from the replacement into my gauge case (because the replacement had scratches and sun fading), re-installed it, and everything is working as expected.

Thanks to everyone who offered ideas and suggestions.

In an effort to help others who may have a similar problem, following is how I finally determined the cause. In addition to conducting all the tests listed earlier in this thread (mostly continuity checks), I also performed a bench test of my gauge (and later the replacement gauge). This indicated the gauge itself was defective.

After removing the gauge from the dash (to make it easier to work with):

1. Check the gauge light - The wire harness with a blue and a black wire is for the light. Connect 12v + to blue and 12v - to black to check the light.

2. Power up the gauge - The yellow and black wires in the main harness are the power leads. Connect 12v + to yellow and 12v - to black. The gauge should initiate its start-up sequence. All LCD segments should light (88 on the RPM gauge, all three oil level arrows and all trim bars. Next the trim bars will go blank and then a bar will appear to "march" from the lowest to highest level).

After the start-up sequence ends, the yellow oil level arrow will be lit. This is normally displayed when the oil level in the remote tank is low.

3. Check the oil level warning (red) arrow - The wire connector with a green/white and a green/red wire is for the green and red oil level arrows. With the gauge powered up, connect a 12v - lead to the green/red wire. The oil level arrow should immediately change from yellow to flashing red. This is what occurs when the oil level in the engine tank is low and the remote tank is also low. Disconnect the 12v - lead from the green/red wire and the arrow should immediately change back to yellow.

4. Check the oil level OK (green) arrow - With the gauge powered up, connect a 12v - lead to the green/white wire. After about 8 seconds, the oil level arrow should change from yellow to green. This is what displays when the oil level in the remote tank is sufficient. Disconnect the 12v - lead from the green/white wire and after about 8 seconds the arrow should change back to yellow.

5. Check for a bad wire harness or connector - In my situation, the wiring harness is soldered directly to the circuit board inside the gauge. Therefore, to check for a bad harness or wire connector, I carefully disassembled the gauge and conducted the tests in steps 3 & 4 above by connecting the 12v - lead directly to the points on the circuit board that the green/red and green/white wires are soldered (thus bypassing the harness and connector). The circuit board is coated with an epoxy-like material to protect it from corrosion, so I had to get under that to ensure a good connection. On my gauge, the behavior was the same, indicating a bad gauge and not just a bad harness, connector or corroded pins/sockets.