PDA

View Full Version : Help...oil pressure guage pegs out.


Ole Miss Rebels
03-26-2007, 12:31 PM
what could be causing this to happen. I have an 05 xstar with mcx. i have had the module changed, the sending unit changed and the guage changed. it only does it intermittently upon cranking. if i turn off the key and re-crank the boat it reads properly. is there anything i am overlooking other than the sending unit, dashboard guage and module? is it possible it could be the oil pump itself? thanks in advance.

bigmac
03-26-2007, 12:37 PM
what could be causing this to happen. I have an 05 xstar with mcx. i have had the module changed, the sending unit changed and the guage changed. it only does it intermittently upon cranking. if i turn off the key and re-crank the boat it reads properly. is there anything i am overlooking other than the sending unit, dashboard guage and module? is it possible it could be the oil pump itself? thanks in advance.
The first thing I'd try is changing to a different oil filter, like a Wix or NAPA 51069. That can have an effect on indicated oil pressure, and it's the cheapest and easiest thing I can think of to try.

cwright
03-26-2007, 01:05 PM
pull your dash if you have to but check your ground clips/connections around and on your pressure guage. If they are daisy chained like my 88PS190, you could have a loose ground on a toggle switch and it will affect your pressure guage. I just had this happen last week-end.

Engine Nut
03-26-2007, 02:12 PM
what could be causing this to happen. I have an 05 xstar with mcx. i have had the module changed, the sending unit changed and the guage changed. it only does it intermittently upon cranking. if i turn off the key and re-crank the boat it reads properly. is there anything i am overlooking other than the sending unit, dashboard guage and module? is it possible it could be the oil pump itself? thanks in advance.

Sounds like an electrical issue to me. Your engine should have a new style oil pressure transducer, digital not analog. The signal from that transducer goes from the transducer to the ECM and from the ECM to the MMDC Box under the dash via a CAN BUS. The MMDC Box then takes the signal from the CAN BUS and distributes it to the appropriate gauges. If I was troubleshooting it, I would connect my scan tool to the datalink connector on the engine and monitor the oil pressure sensor voltage. If that voltage spiked to 5 volts during the crank cycle on the scan tool, the problem is most likely on the engine ... a wiring harness, sensor or ECM issue. If it doesn't spike to 5V on the scan tool then I would look at the boat ... he harness from the engine to the dash, the MMDC Box, the gauge or the gauge wiring or the key switch.

I have attached a copy of the engine wiring diagram for you if that might help.

Engine Nut

SierraDump
06-28-2008, 08:51 PM
Not to dig up an old thread or anything - but if you have the dummy light sending unit hooked to a pressure guage, it will PEG out. Make sure you have the right sending unit for your guage...