PDA

View Full Version : Oil Pressure Gauge Wiring Question


dummy
10-03-2009, 11:32 AM
Oil pressure gauge not working. Reads Zero all the time. Here's the story:

'00 Maristar 230VRS, 330hp LTR engine. Gauges all worked before I brough it in for servicing last year. Got it back and had all the gauges would go on/off intermittently. I suspected bad ground, checked the battery, engine, etc. Found a loose nut by feel on one of the gauges and tightened by hand and all the gauges now work except for the oil pressure, which always reads zero. Figured the sending unit had died, so I used the boat about 10hrs w/ no oil pressure gauge. Replaced the sending unit before my last trip yesterday and still nothing. Gauge reads zero.

Found an orange wire with a black stripe and a bullet-type terminal loose and not connected to anything. Looks and feels like it comes off the oil pressure gauge. Figuring (without pulling my dash apart to confirm) they probably yanked it out of one of the plastic multi-connectors when trying to diagnose my ignition problems last year when it was in for servicing.

Question for all those former/current service guys: anybody know where that orange/black wire should connect to? If I knew the wire colors going into the right connector and which pin terminal it's supposed to go into I'm hoping I can just shove it back in without ripping my dash apart. Doesn't look like it's a fun job to get to the back of those gauges.

TMCNo1
10-03-2009, 01:52 PM
Oil pressure gauge not working. Reads Zero all the time. Here's the story:

'00 Maristar 230VRS, 330hp LTR engine. Gauges all worked before I brough it in for servicing last year. Got it back and had all the gauges would go on/off intermittently. I suspected bad ground, checked the battery, engine, etc. Found a loose nut by feel on one of the gauges and tightened by hand and all the gauges now work except for the oil pressure, which always reads zero. Figured the sending unit had died, so I used the boat about 10hrs w/ no oil pressure gauge. Replaced the sending unit before my last trip yesterday and still nothing. Gauge reads zero.

Found an orange wire with a black stripe and a bullet-type terminal loose and not connected to anything. Looks and feels like it comes off the oil pressure gauge. Figuring (without pulling my dash apart to confirm) they probably yanked it out of one of the plastic multi-connectors when trying to diagnose my ignition problems last year when it was in for servicing.

Question for all those former/current service guys: anybody know where that orange/black wire should connect to? If I knew the wire colors going into the right connector and which pin terminal it's supposed to go into I'm hoping I can just shove it back in without ripping my dash apart. Doesn't look like it's a fun job to get to the back of those gauges.


What are the colors coming off the oil pressure sending unit? The signal wire from the sender to the gauge should be the same color, unless someone has rewired it with different color wire or spliced in a different color.

JimN
10-03-2009, 02:08 PM
What are the colors coming off the oil pressure sending unit? The signal wire from the sender to the gauge should be the same color, unless someone has rewired it with different color wire or spliced in a different color.

Look at the oil pressure sender- it has one wire. Turn the key ON and have someone connect the wire to ground. It doesn't matter how this happens, the gauge and MDC are looking for a resistance range. If it moves, it's the sender and if not, it's the wire, gauge or MDC.

JimN
10-03-2009, 02:09 PM
Oil pressure gauge not working. Reads Zero all the time. Here's the story:

'00 Maristar 230VRS, 330hp LTR engine. Gauges all worked before I brough it in for servicing last year. Got it back and had all the gauges would go on/off intermittently. I suspected bad ground, checked the battery, engine, etc. Found a loose nut by feel on one of the gauges and tightened by hand and all the gauges now work except for the oil pressure, which always reads zero. Figured the sending unit had died, so I used the boat about 10hrs w/ no oil pressure gauge. Replaced the sending unit before my last trip yesterday and still nothing. Gauge reads zero.

Found an orange wire with a black stripe and a bullet-type terminal loose and not connected to anything. Looks and feels like it comes off the oil pressure gauge. Figuring (without pulling my dash apart to confirm) they probably yanked it out of one of the plastic multi-connectors when trying to diagnose my ignition problems last year when it was in for servicing.

Question for all those former/current service guys: anybody know where that orange/black wire should connect to? If I knew the wire colors going into the right connector and which pin terminal it's supposed to go into I'm hoping I can just shove it back in without ripping my dash apart. Doesn't look like it's a fun job to get to the back of those gauges.

"Found an orange wire with a black stripe and a bullet-type terminal loose and not connected to anything. "

Where? Those aren't the color for the oil pressure sender. What color is the wire on the sender?

dummy
10-03-2009, 10:22 PM
"Found an orange wire with a black stripe and a bullet-type terminal loose and not connected to anything. "

Where? Those aren't the color for the oil pressure sender. What color is the wire on the sender?

Wire coming from the sending unit on the engine is Lt. Blue.

The Orange/Blk wire is under the dash and feels like it comes from the area the oil pressure gauge is in. I'm sure the Lt. Blue wire goes into the gauge, but I figured the Orange/Blk one may come out of it. I dunno.

There are also a couple white terminal connectors under there that look close enough to have that Orange/Blk wire going into it.

I'll try grounding it when I get a chance and see what if anything the gauge does.

JimN
10-04-2009, 12:04 AM
Wire coming from the sending unit on the engine is Lt. Blue.

The Orange/Blk wire is under the dash and feels like it comes from the area the oil pressure gauge is in. I'm sure the Lt. Blue wire goes into the gauge, but I figured the Orange/Blk one may come out of it. I dunno.

There are also a couple white terminal connectors under there that look close enough to have that Orange/Blk wire going into it.

I'll try grounding it when I get a chance and see what if anything the gauge does.

Lt blue or tan with a Lt blue tracer?

I wanted to make sure where the orange/black wire was since it hadn't been specified originally. The orange/black wire doesn't go to any of the gauges- you sure it's not orange/brown? Another end to that may be at the ECM but don't connect anything to it on either end.

dummy
10-04-2009, 12:34 PM
Wire to the sending unit is solid Lt Blue.

Wire under the dash is definitely Orange with a Black tracer (Orange/Blk). I grounded it and turned the Key on and the gauge did nothing. Who knows what that Orange/Blk wire is, but as of now I'm guessing it's not related to my gauge issues.

I was also able to stick my head up in there enough to just get a glimpse of the back of the oil pressure gauge and none of the wires coming out of the oil pressure gauge connector are orange/blk, so who knows what this thing is from.

Right now I'm guessing it's probalby a bad MMDC computer since I was getting some intermittent gauge problems again yesterday. The gauges would go to zero or freeze - Tach would stay at 3,000rpm or wherever even at idle, fuel gauge was varying from 1/2-3/4-Full, etc.

Looks like it may be time to call MYMC. Damn.

JimN
10-04-2009, 03:43 PM
Wire to the sending unit is solid Lt Blue.

Wire under the dash is definitely Orange with a Black tracer (Orange/Blk). I grounded it and turned the Key on and the gauge did nothing. Who knows what that Orange/Blk wire is, but as of now I'm guessing it's not related to my gauge issues.

I was also able to stick my head up in there enough to just get a glimpse of the back of the oil pressure gauge and none of the wires coming out of the oil pressure gauge connector are orange/blk, so who knows what this thing is from.

Right now I'm guessing it's probalby a bad MMDC computer since I was getting some intermittent gauge problems again yesterday. The gauges would go to zero or freeze - Tach would stay at 3,000rpm or wherever even at idle, fuel gauge was varying from 1/2-3/4-Full, etc.

Looks like it may be time to call MYMC. Damn.

When I said to ground the wire, I meant the one that's connected to the oil pressure sender.

Check the resistance from the MDC to the battery negative. If it's more than 1 Ohms, address that and get it below .1 Ohm.

Have you tried disconnecting the battery for about 10 minutes and reconnecting it? That sometimes helps.

dummy
10-05-2009, 01:56 AM
When I said to ground the wire, I meant the one that's connected to the oil pressure sender.

Check the resistance from the MDC to the battery negative. If it's more than 1 Ohms, address that and get it below .1 Ohm.

Have you tried disconnecting the battery for about 10 minutes and reconnecting it? That sometimes helps.

D'oh! Eh, just living up to my user name, I guess.

I brought the boat home from Havasu with me, so I'll mess with it a little tomorrow as time allows. No on the battery thing as well. I'll ground the sending unit wire, then try the battery dealio, then will break out the multi-meter and check the MDC if need be.

Thanks Jim.

dummy
10-05-2009, 03:26 PM
Well, grounded the wire on the sending unit and the gauge doesn't move when key-on. Looks like I can rule out the sending unit, but since it's new I knew that already.

Busy working on the M-715 the rest of the day, but I'll do the battery disconnect and then check the MDC resistance tomorrow. I think I'll also pull my MDC apart just to see if there's any water in it.