I'd think that a light switch is closed when engine is off and open when engine is up and running. Tomas <-----Ursprungligt Meddelande-----> From: Joseph F. Byrd, Jr. [byrdjf@embarqmail.com] Sent: 1/9/2016 4:36:10 AM To: detomaso@server.detomasolist.com Subject: Re: [DeTomaso] Oil Pressure Gauge Just saying....When I google NAPA OP6091, I get a SWITCH. You could use a DMM and see if not running you have "open" and once cranked "closed". A sender would have about 70 ohms not running and approaching 0 running. I would still want a mechanical gauge locally. ( I like Marshell's for automotive) Joe/NC -----Original Message----- From: DeTomaso [mailto:detomaso-bounces@server.detomasolist.com] On Behalf Of Mike Drew via DeTomaso Sent: Wednesday, August 31, 2016 20:37 PM To: mbefthomas@comcast.net; detomaso@server.detomasolist.com Subject: Re: [DeTomaso] Oil Pressure Gauge In a message dated 8/31/16 17 26 15, mbefthomas@comcast.net writes:

I'm trying to figure out why I'm getting a pegged reading on my oil pressure gauge. It will show normal pressure as the car starts, but soon after pegs to the right and stays there. Everything runs fine otherwise. I've swapped out the pressure sender, NAPA OP6091, and it's still pegging, so I'm suspecting the gauge. Anything else I could check?

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Calling Bill Taylor! That is, assuming it's an electrical. You can't make that assumption though.

I'm trying to figure out why I'm getting a pegged reading on my oil pressure gauge. It will show normal pressure as the car starts, but soon after pegs to the right and stays there. Everything runs fine otherwise. I've swapped out the pressure sender, NAPA OP6091, and it's still pegging, so I'm suspecting the gauge. Anything else I could check?

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Calling Bill Taylor! That is, assuming it's an electrical. You can't make that assumption though. I *think* I may have stumbled across something. Doing some primitive Google research, I confirmed what I thought I knew, which is that the oil

I *think* I may have stumbled across something. Doing some primitive Google research, I confirmed what I thought I knew, which is that the oil pressure gauge works by taking 12V power in, which runs across the gauge, then out to the sender unit, which is a variable ground. The reading given by the gauge depends on the resistance of the sensor unit; this in turn is determined by the engine's oil pressure. Extremely high readings after a cold start, if they are accurate, mean the pressure relief valve near the pump and filter has probably stuck. The engine should be switched off or the oil filter could burst. I have a mechanical oil pressure gauge which threads into the hole normally occupied by the electric sender. It is used to 'sanity check' the readings on the gauge. It's the first troubleshooting tool; if the mechanical gauge reads high, you have an engine (or at least oil filter) problem. If it reads normally, you have an electrical problem. I could mail it to you tomorrow and you would have it by the weekend? Let me know if you would like to try it out. Mike _______________________________________________ Detomaso Email List is not managed by POCA Posted emails must not exceed 1.5 Megabytes DeTomaso mailing list DeTomaso@server.detomasolist.com http://server.detomasolist.com/mailman/listinfo/detomaso To manage your subscription (change email address, unsubscribe, etc.) use the links above. Members who post to this list grant license to the list to forward any message posted here to all past, current, or future members of the list. They also grant the list owner permission to maintain an archive or approve the archiving of list messages. I'd think that a light switch is closed when engine is off and open when engine is up and running. Tomas <-----Ursprungligt Meddelande-----> From: Joseph F. Byrd, Jr. [byrdjf@embarqmail.com] Sent: 1/9/2016 4:36:10 AM To: detomaso@server.detomasolist.com Subject: Re: [DeTomaso] Oil Pressure Gauge Just saying....When I google NAPA OP6091, I get a SWITCH. You could use a DMM and see if not running you have "open" and once cranked "closed". A sender would have about 70 ohms not running and approaching 0 running. I would still want a mechanical gauge locally. ( I like Marshell's for automotive) Joe/NC -----Original Message----- From: DeTomaso [mailto:detomaso-bounces@server.detomasolist.com] On Behalf Of Mike Drew via DeTomaso Sent: Wednesday, August 31, 2016 20:37 PM To: mbefthomas@comcast.net; detomaso@server.detomasolist.com Subject: Re: [DeTomaso] Oil Pressure Gauge In a message dated 8/31/16 17 26 15, mbefthomas@comcast.net writes: pressure gauge works by taking 12V power in, which runs across the gauge, then out to the sender unit, which is a variable ground. The reading given by the gauge depends on the resistance of the sensor unit; this in turn is determined by the engine's oil pressure. Extremely high readings after a cold start, if they are accurate, mean the pressure relief valve near the pump and filter has probably stuck. The engine should be switched off or the oil filter could burst. I have a mechanical oil pressure gauge which threads into the hole normally occupied by the electric sender. It is used to 'sanity check' the readings on the gauge. It's the first troubleshooting tool; if the mechanical gauge reads high, you have an engine (or at least oil filter) problem. If it reads normally, you have an electrical problem. I could mail it to you tomorrow and you would have it by the weekend? Let me know if you would like to try it out. Mike _______________________________________________ Detomaso Email List is not managed by POCA Posted emails must not exceed 1.5 Megabytes DeTomaso mailing list DeTomaso@server.detomasolist.com http://server.detomasolist.com/mailman/listinfo/detomaso To manage your subscription (change email address, unsubscribe, etc.) use the links above. Members who post to this list grant license to the list to forward any message posted here to all past, current, or future members of the list. They also grant the list owner permission to maintain an archive or approve the archiving of list messages.