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Constant Sensor horn at high speed - 50mph

T

TexExp

New member
Hi all,

I have a 1990 200 hp V6
Smokes a little at startup but runs fine and idles fine (for a 24 yr old motor).

It will run 30-40 mph all day long.
When I run up to 50 MPH, after a minute or so, the constant horn will sound.

My mechanic recommended coming down off plane, put in neutral and squeeze the fuel bulb and check for firmness.
If firm, he suggested disconnecting the horn, since they are prone to failure and the part is no longer available (apparently due to failures).

Any other advice or does this sound reasonable?
thanks!
 
Is it a VRO motor? Might be a VRO pump issue. Theres different things that will set off the hot horn. I've had loose battery terminals set off a hot horn before. I've had a bad pack make the hot horn sound before. Your symptoms are pretty much similar to one I had in two years ago that had an intermittent horn. Sometimes it would sound off, sometimes it wouldn't. Ended up being a bad pack.
 
ripperace said:
Is it a VRO motor? Might be a VRO pump issue. Theres different things that will set off the hot horn. I've had loose battery terminals set off a hot horn before. I've had a bad pack make the hot horn sound before. Your symptoms are pretty much similar to one I had in two years ago that had an intermittent horn. Sometimes it would sound off, sometimes it wouldn't. Ended up being a bad pack.
Click to expand...

thanks.
My mechanic is suggesting:

Step one - crawl back there running 50 mph when the horn goes off and pump the oil bulb - if firm, than oil or VRO not the problem
Step two - " " " " " " gas bulb - If pumping it does not make the sensor go off than fuel pressure is OK.

Step three - Disconnect vacuum switch, if horn still sounds, it is overheating problem and not fuel/oil related.
If the horn doesn't go off, than it is a bad switch. (doesn't really sound foolproof to me...) I guess it is the only way through process of elimination.


Seems like there would be a way to test these switches.
 
Turns out itwas a bad thermostat.
The mechanic had to join me at the lake since there was no way to duplicate the high speed failure at his shop.


After the hornwent off, he took the cover off and simply put his hand on the left side, thenthe right side.
Left side hot,right side cool.
We replacedboth thermostats, problem solved.
Thanks!
 
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