Can bad oil pressure gauge cause limp mode?

[Tanner]

I've been getting this limp mode problem on the new motor that I've been trying to diagnose. The boat ran fine for 2 days last year before going into limp mode. I've been limited on time, so haven't really been screwing with it because I was sureeee it was the EIDBS system sensing a dead house battery. But that wasn't the problem apparently. I've also had a dead oil pressure gauge but had a mechanical gauge installed and it showed good, so I wasn't concerned. In addition the sending unit (I can only find one, although I think someone mentioned there is 2 on this motor...06 340 MP) is brand new. New batteries and the boat went into limp mode again after about 20 mins. Well I decided to swap out the gauge and in a pinch purchased 100 psi gauge from O'reilly's b/c it's all they had in stock that even remotely matched. It came with it's own sending unit since it was a 100 psi gauge, I knew I'd need a diff. one anyways. Well problem is now gone.

So the 2 things that have changed that cured the problem..... I've changed the sending unit and I've put in a new gauge. I guess it's possible I got a bad sending unit, but what are the chances the thing went bad after 2 days????

So that's why I'm wondering if there is anyways possible for the motor to sense the gauge is reading 0 psi and throw it into limp mode?

[chpthril]

It was probably a bad sending unit, not gauge. But yes, I think the ECM monitors the pressure.

Your new engine may not have been a complete asm as they would install in a boat during construction, but instead, a long block, and the accessories and electronics swapped over from the old.

[Tanner]

You are correct, it was just a long block. I did the swap.

I'm just shocked the brand new sending unit I put on went bad after just 2 days! I could see it being bad from day one, but kind of shocked it worked and went bad. Guess it happens though.

[jwanck11]

That is odd though Tanner. My oil pressure gauge (or sending unit) is shot (was reading 0) although we ran the boat for well over an hour this weekend without limp mode. She purred like a kitten regardless of where the throttle was.

[Tanner]

Well, I'm leaning to the sending unit being bad! As it will def. trip the alarm. Just odd that it went bad after only 2 days!

[jwanck11]

That is odd. I would think that if the sending unit is bad, it will be picked up by the computer. If the gauge is bad, perhaps nothing would be the wiser...