Oil pressure sender fitting broke off.

[Mi_fiveo]

I’m currently looking for a similar size wire. I can’t fathom why it will change anything though. I could see if I had low oil pressure across the board then maybe it would be from a bad wire but the low oil pressure only happens after a hot engine and idle speed. Was your issue similar or different? Did you have an alarm as well and after a new wire it was fixed??

 

[Mi_fiveo]

I changed it out. May as well for how quick and easy it is. Won’t know if it changed anything until I get out on the water again and run the engine until hot. I appreciate all of the comments and ideas to help me try to fix this issue. You guys are top notch

 

[GeorgeDes]

You said this is only showing up with a hot engine and that when you ran it on muffs you did not get it up to a high temp? If so, take the boat out on the water wit the mechanical gauge attached and see what the gauge reads once you get to the higher temperatures where the problem was occurring. If it doesn’t react the same way as before, then try the wire change. On mine, the dash gauge has a telltale or light and audible alarm that are connected in line. If the dash gauge read low, the telltale light and alarm sound. As a backup to this system, the 5.7 GSI has another oil pressure switch that is connected to the ECM. If this switch detects an issue with oil pressure it will put the engine in limp mode. Mine never went into limp mode so I was confident it was not really a pressure issue. The mechanical gauge confirmed that and I then went through troubelshooting the dash gauge/oil sender/wiring.

 

[alldodge]

With all due respect George, the sender is either shorting out due to heat, or its bad. Don't see any way wire will work one time and when it gets warmer, it works another, senders yes, but not wire.

Boat helm gauges have no effect on the ECM

 

[GeorgeDes]

I thought that too but changing the wiring fixed the problem in my case. It was the last thing I tried after replacing the Four Winns dash gauge unit, oil pressure sender, cleaning contacts and grounds, checking pressure with the mechanical gauge, etc. Was pretty much at wits end with it. I even had an oil analysis done.

 

[Mi_fiveo]

Tried it out and it would still get the alarm. Switched out the synthetic sae 30 for synthetic Mobil 1 15w50. Problem is gone now. The 30 must be too thin when hot to get enough pressure. I get 50 psi cruising and 20 in idle when hot. All that screwing around and the oil viscosity was the culprit.

 

[GeorgeDes]

Glad you finally got this sorted out! I know how frustrating chasing some of these gauge issues can be!