On 1 May 2007 at 14:21, Jim Dwyer wrote: > I removed then replaced the Oil Pressure Switch on the engine > block... I plugged the 3 wires back in their correct positions.
Are you absolutely positively sure you hooked the wires back up the same way???? If you didn't screw the sender back into the block the same amount, the terminal would all be in different locations. Here's a test. Get an ohmmeter, unplug the wires from the sender, and check resistance between the various pairs of terminals. Do it once with the engine off and once with the engine running. Here is what you should find. With the engine off, one pair will show a closed circuit (zero ohms), the other two pairs will show an open circuit (infinite ohms). With the engine running and oil pressure up, you'll get a different pair showing a closed circuit. Note which terminal is common to those two closed-circuit readings. The ground wire should connect to that one. Its behavior is to ground one of the other two when oil pressure is up, ground the other when oil pressure is down. Now note which of the other two terminals was grounded when oil pressue was down, i.e. the engine off. That one should connect to the oil pressure light. You see, when you energize the ignition, it powers the oil pressure bulb. If the pressure is down, that sender switch completes that circuit to ground so the bulb turns on. The other terminal goes to the anti-run-on valve. It works like this. When you turn off the ignition, it de-energizes the ignition and oil pressure bulb but it energizes the wire to the anti-run-on valve. As long as the oil pressure is up from the engine still spinning, that terminal is grounded and so completes the circuit for the a-r-o valve. After a moment the engine stops and the oil pressure falls, so the sender switches back to grounding the oil pressure light but not the a-r-o valve. Since you've turned the ignition off, the oil pressure bulb won't come on, and the a-r-o valve won't stay engaged because the oil pressure won't throw the sender switch that direction. I didn't bother to work out all the ways you could have mis-wired things, but it sound like you have found a combination that causes the energized-when-igntion-is-off a-r-o wire to be connected to the oil pressure switch, grounding through some other circuit. -- Jim Muller [EMAIL PROTECTED] '80 Spitfire, '70 GT6+ -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.2/782 - Release Date: 5/1/2007 2:10 AM Your messages not reaching the list? Check out http://www.team.net/posting.html === This list supported in part by The Vintage Triumph Register === http://www.vtr.org === Help keep Team.Net on the air === http://www.team.net/donate.html === unsubscribe/change address requests to [EMAIL PROTECTED] or try === http://www.team.net/cgi-bin/majorcool === Other lists available at === http://www.team.net/mailman/listinfo === Archives at http://www.team.net/archive === http://www.team.net/the-local === Edit your replies!
