Go Back   TeamTalk > Maintenance Tips, How-tos and Refurbishing Topics > General / Other

Thread Tools Display Modes
Old 08-11-2013, 09:27 PM
zonanavystar zonanavystar is offline
TT Newbie
Join Date: Aug 2013
Boat: 2001 Mastercraft Prostar 209 Indmar Predator 310 HP
Location: West Coast
Posts: 24
oil pressure readings erratic

I posted this in "electrical," Perhaps someone here might be able to help as well.

the boat: 2001 Prostar 209 Indmar Predator 310 HP

Problem: Oil pressure reading fluctuating during all operating conditions.

I know the problem is somewhere from the oil pressure sending unit, the MDC or the gauge itself. I'm hoping someone can shed some light into where the problem lies. Troubleshooting broken into potential problem area.

Oil pressure sending unit: Did the ground test for all analog oil pressure sending units. Gauge showed zero with open circuit, then showed max with attaching sending unit wire to ground. Leads me to believe its the sending unit.

MDC: When I first bought the boat, one speedometer was disconnected. Turned out to be for a good reason. It appears one of the baffles or something inside the MDC is ruptured as water got into the MDC from that pitot line. That caused erratic readings in the oil pressure, voltmeter and temperature gauge. Sometimes the gauges wouldn't register anything. Pulled that pitot back off, let it dry out, and now temp is solid, voltmeter is solid, but the oil still fluctuates inappropriately. ADDITIONALLY, on occasion I've had some of the gauges not register during a run. On the next "motor on" cycle said gauge reads the correct indication. All except the oil pressure, this one always seem to fluctuate.

Oil Pressure gauge: Now, I don't know if this is condoned or not, and I'm showing a little inexperience here... I swapped the oil pressure harness on the back of the gauge to the water temp gauge (I did this because all the gauges seem to be the same electric gauges with a different face... figuring all the real data is coming from the MDC). When I swapped in the oil pressure harness to the water temp gauge, the gauge went to the middle (about where it should be for warm oil), however it did not return to zero when I shut the motor down, so I'm not sure my similar gauge theory holds water. I then swapped the voltmeter harness to the oil pressure gauge, and the oil presure gauge showed the same erratic movement as if it still had the oil pressure harness attached like I was seeing earlier, which is the only reason I'm leaning towards the oil pressure gauge having problems.

Sorry for the long post, but I'm hoping someone can point me in the right direction. Thanks for looking.
Reply With Quote
Old 08-12-2013, 08:47 AM
76S&S's Avatar
76S&S 76S&S is offline
MC Devotee
Join Date: Jun 2007
Boat: 2002 X Star
Location: Lake Tuscaloosa, AL
Posts: 2,358
The sending unit is cheap to rule out and can be purchased at your local auto parts store. I would start there.

I had to replace mine a few years ago.
Being on the water is best, but when I'm not on the water I'm on TT.

2002 X Star
Sold - 76 S&S
Reply With Quote
Old 08-12-2013, 06:10 PM
petermegan's Avatar
petermegan petermegan is offline
TT Enthusiast
Join Date: Dec 2010
Boat: 2000 Matercraft Prostar 190, LTR330,powerslot,PP,heater
Location: South Australia
Posts: 477
Originally Posted by 76S&S View Post
The sending unit is cheap to rule out and can be purchased at your local auto parts store. I would start there.

I had to replace mine a few years ago.
*2, mine was giving strange readings and it was the sender unit. Cheap to try. Have Fun.
Reply With Quote
Old 07-10-2014, 11:38 PM
Gamble's Avatar
Gamble Gamble is offline
TT Enthusiast
Join Date: May 2008
Boat: Mastercraft Prostar 209 310 Predator
Location: Southwest
Posts: 434
Where is the sending unit located on a predator tbi? Mine is doin same thing but only at idle......thanks!
Reply With Quote
Old 07-11-2014, 08:07 AM
curver900 curver900 is offline
MC Devotee
Join Date: Aug 2013
Boat: Mastercraft, prostar 2001 205v
Location: midwest
Posts: 2,328
right by the oil filter. coneshed shaped with a wire to it.

Another option would be to run some carb cleaner or such into it... that may help too if it is just a piece of crud stuck in there...
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -4. The time now is 04:32 AM.