1888 225 V6 Looper VRO No OIl Horn, OIl Level Droppng, Tach Signal Bad?

[Greg_E]

Newly rebuilt engine (by me). I couldn't run the engine on the stand long enough for the warning horn to sound.
I am running an aux. tank with extra oil to prevent damage.

Put it in the water and the VRO warning horn goes off after a few minutes and increases in frequency as the RPMS increase. Tone is a On/ Off horn at about 1 sec intervals at idle.

One odd thing happened for a brief period and then resolved itself. When I would restart the engine the horn would sound and the tach was reading 4000RPM even though it was just idling. After letting the engine sit for a while, the tach has returned to normal operation, but the horn is still sounding after running for a few minutes.

I filled the oil tank to the very top of the neck and after running the level is dropping.

Both the fuel pump and regulator were working normally when the engine was removed for the rebuild.

I didn't have all my tools with me, so I came home to get them so I can do a better job troubleshooting this. I do have a DVA adapter for my meter but because the tach seems to be workiing normally, at least for now, I do not expect to to find anything. After checking the tach signal at the VRO connector, what would be the next step.? Power ( purple) and ground( black) were checked and are OK .

If it's not a wiring problem, I'm leaning toward the VRO internal sensor as the problem. I've never had a VRO fail due to a bad sensor but there's a first time for everything. I do have a brand new VRO pump and a used good voltage regulator.

Any troubleshooting tips or testing shortcuts are appreciated.
Thanks in advance for any help.

 

[flyingscott]

Did you follow the exact orocedure for reconnecting the VRO.

 

[Greg_E]

Thanks for the reply.
I checked the tach signal with the DVA adapter on my meter at the VRO plug gray and black wires. The reading was about 11.4 volts which is in the normal range. I have no explanation as to why the tach was reading 4000 RPMs at idle but it has not done it since. I had followed the procedure for installing the pump making sure the oil supply line was full of oil and then pumping the oil primer bulb with the engine running to get oil up into the pump. I've changed these several times in the past and never had this issue. I put a clear vinyl tube on the oil inlet just to be sure it was drawing oil and it is. I 'm thinking about running premix for both engines. For now I am just going to run double oil premix from the aux tank until the engine is broken in with the VRO disconnected.