Oil Sender pegged when ignition is on. Please Help!

[Friscoboater]

I am finishing up my restoration and I notice when I turn on my ignition the oil gauge pegs to the right. I remove the lead on the engine and it goes back to zero. So I replaced the oil sender, and it still does it. Do gauges go bad, or is there somewhere else I need to look?

Also I put on a new alternator because the old one died. When I rev the engine the Volts drop to 12 instead of 14, and once I go back to idle or around 1500 rpm it goes back up. Is that normal?

 

[paultjohnson]

Re: Oil Sender pegged when ignition is on. Please Help!

You didnt put teflon tape around the sending unit threads did ya ?

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

No I didn't. The new sender is doing the same thing the old one was.

 

[paultjohnson]

Re: Oil Sender pegged when ignition is on. Please Help!

No I didn't. The new sender is doing the same thing the old one was.

Yeah but I was thinking if the 1st one failed just do to a malfunction, wear and tear, whatever, and then you put a new one in with Teflon tape that prevented it from being grounded, you could have the same end result. pegged. But ya know what, I think I may have it totally bass akwards. :facepalm:Ya might end up with the opposite results....never mind...somebody...help...... Ok back to my nap.

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

I just went and purchased a mechanical oil sender to make sure we had pressure, and it worked perfect.

So, if I have a new oil sender, I am thinking we have a bad gauge.

 

[HT32BSX115]

Re: Oil Sender pegged when ignition is on. Please Help!

No I didn't. The new sender is doing the same thing the old one was.

Looks like the "new" sender is as bad as the old sender, huh?

The oil pressure circuit is just a simple variable resistor (the sender) a single piece of wire, from the back to the front, a gage and a power source.

The ground system completes the circuit. If you touch a wire that is grounded to the sender, the gage should "peg" (if the wire from the sender to the gage is still connected)

If you disconnect the wire from the sender and touch IT to ground, the gage should peg.

If you turn on the "key" and the gage is already "pegged" (see above!!)............I.E. the wire is grounded someplace between the sender and the gage.............OR the gage is defective or grounded internally!

By the way, I *just* discovered your Youtube channel! Awesome job on the boat! That is fantastic! (And of course, sincere condolences on your recent loss.....we've all been there....)

Regards,


Rick

 

[Doernuth]

Re: Oil Sender pegged when ignition is on. Please Help!

or bad wiring, check the ground on the guage.

You said the guage pegs when you turn on the ignition, any change when you start the engine? or is that with the engine running?

Other than the voltmeter, are the other guages working properly, or at least appearing too....

Don't spend a bunch of money on a new guage for a bad wire or dirty terminal.

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

Al gauges work fine. I even ran a separate sender wire just to check it. At least I have pressure.

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

I still cannot figure this out.

 

[Dshow]

Re: Oil Sender pegged when ignition is on. Please Help!

At the gage, disconnect the sender wire. What is the resistance from the wire to the case of the gage?

 

[scoflaw]

Re: Oil Sender pegged when ignition is on. Please Help!

just had the same problem. Replaced sender. ran separate wire. Solution. New gage. All good now.

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

I am thinking that is what I need to do. The problem is that all my gauges match nicely, and I hate mismatched stuff.

 

[04fxdwgi]

Re: Oil Sender pegged when ignition is on. Please Help!

You disconnected the lead at the sender and gauge returns to zero, indicating there is no short anywhere. If there was teflon tape on threads, the gauge would read very low or zero, so that's OK. I would try another sender. Even though you just replaced it, I've seen em bad out of the box. Not often, but it happens. The sender should read between 240 ohms (zero oil pressure / zero reading on gauge) and 33 ohms (80 PSI, I think it is, on the gauge), which is same value for a temp gauge sender (may be able to connect oil sender wire to temp sender on warm engine and read mid-scale on gauge, if gauge is good) . If the sender is giving you these values with the lead disconnected and using an ohmmeter thru it to ground, then it's the gauge. If values are off, it's the sender.

 

[scoflaw]

Re: Oil Sender pegged when ignition is on. Please Help!

I bought an OEM guage from the sea ray dealer for my 2000. Check ebay as well.

 

[Bt Doctur]

Re: Oil Sender pegged when ignition is on. Please Help!

Are you sure your hooked up to the gauge and not the temp alarm switch

 

[04fxdwgi]

Re: Oil Sender pegged when ignition is on. Please Help!

Are you sure your hooked up to the gauge and not the temp alarm switch

AHHH... Good suggestion, there BT. Didn't even think about that one. I would have expected him to just disconnect the one, but stranger things have happened. Maybe the dealer gave him an alarm sender instead of the gauge sender..

 

[Friscoboater]

Re: Oil Sender pegged when ignition is on. Please Help!

I would love to try any of these suggestions, but when I have gotten home from work this week it has been at least 110 degrees out, and that is just too hot.

 

[707airbrush]

I have a Four Winns that wont start. OMC cobra, changed the electric fuel pump last year and boat ranfor 9 hours. Now it will only run with carburetor cleaner spraying down the throat of the carburetor. Changed oil pressure sending unit and needle pegs out now when you turn the key on. If you crank it the pressure gauge goes from pegged out down to 40 pounds pressure.