Is the VRO tied in with the tach and other motor electronics?

[nebraska_woody]

Hi all, I was at my mechanics place the other day, and he said that if I didnt' replace the VRO on my 89 GT200, that possibly the tach and other electronics may or may not operate correctly. The reason I say this is because my tach does not work at all, except for the back-lighting. It sits at zero with or without the motor running. I asked him to check the rectifier and he said that mine was putting out 11 to 12 volts to the tach where it was supposed to only put out between 6-9 volts. To me this doesn't seem logical since we're dealing with a 12 volt system overall. Does this make sense to anyone.... I'm just hoping he's not trying to pull a fast one over on me and get some last minute income at the end of the year. Now that I have my manual, I am going to do some repairs that the motor needs this winter on my own, but I was just curious about the information that they gave me on this topic. Thanks for any help!!

 

[Skyhigh]

Re: Is the VRO tied in with the tach and other motor electronics?

The gray wire on the rectifier should be 3 to 5 volts AC current at idle.

 

[seahorse5]

Re: Is the VRO tied in with the tach and other motor electronics?

The gray wire should have about 9 volts or better using a peak reading voltmeter. You can easily check to see if the VRO is affecting the system by disconnecting the 4 wire connector to it. The VRO uses the tach signal to compare the outboard rpm with the number times the pump pulses over a period of time, if something acts up, then the alarm sounds off. If the tach signal is not working, perhaps due to a charging system problem, then the oil alarm is not operational either.<br /><br />There is a detailed troubleshooting guide in the late model service manuals. If the dealer mechanics are factory trained, this troubleshooting procedure was covered.