Need a little help with this one!!

zielke

Member
Jul 8, 2009
80
West Coast Wisconsin - LaCrosse.
Boat Info
1998 400DA
Engines
3116-caterpillars
I've got a 98 400 dancer with 3116 CATS. Approximately 1400 hours. Last week while cruising I brought the boat down off of plane, went to idle cruising (5minutes) during this idle time I noticed that my port side motors oil pressure gauge maxed out to 100+ soon after that the alarm sounded and the motor shut off. I was shocked and startled at first and started the port motor again. Everything seemed fine (oil pressure went to normal) I soon anchored and killed both motors and went to the engine room fearing the worst. Everything was 'normal'. Check the motor for any oil loss and filter break. Checked oil level also. Had the admiral start the motors and bring them both up to 1000 rpm. The mechanical gauges on top of the motors showed normal oil pressure and coolant temperature. We pulled the anchor and headed back home and our normal pace. Oil pressure gauge was in the normal range. Once I brought the boat back down to idle, oil pressure again went back to a high reading without an alarm or motor shutting down. Back at the dock I went back to the engine compartment and looked for a loose wire on the Oil pressure sending unit. I can feel a small movement of playing on the wire but not enough to fix the problem. Do I check the gauge on the dash also? I believe it's a grounding issue because the gauge maxed out. If it failed it would've went dead? Right? Any and all suggestions please!
 
Sounds like a question for the mighty Frank Webster! Sorry to hear Chris. Keep me posted.
 
Usually a gauge maxing out is a result of grounding it out. I'm by no means an expert, or even all that knowledgeable about diesels, but I would put a new connector on the sender wire that you say you found a little bit of play on. Then I would check the connections on the back of the gauge mounted on the motor, and the gauge in the dash.
Anything less than tight clean connections can cause crazy problems like this.
 
Odd the engine shut down and an alarm was sounding in conjunction with a high gauge reading. The systems monitor and alarm have a separate and independent oil pressure switch on the engine which upon low oil pressure will provide the signal for the systems monitor to alarm. The oil pressure gauge has an oil pressure sender/dashpot which is mounted on the side of the engine. The gauge and sender wire is light blue and the system monitor and switch has a blue wire. What is common to these two items? Not much.. And what is common to bringing the throttle back to idle to cause the alarm and high gauge reading? Even less. The only thing I can think of is part of the wire harness is interfering with the throttle mechanism and shorting... Maybe check under the helm where the throttle mechanism is.
 
I think about the only thing that can cause the engine to shut down, other than the obvious mechanical or electrical failures, is the halon system. If the halon system gets a discharge (fire) signal, it will shut everything down. Try disengaging the halon system on the dash it this happens again and see if it has any effect. IN the meantime, check the wiring for the halon system and see if you see a loose connection or perhaps a butt splice that needs to be cut out and replaced.
 
I would check that all is right with the world inside the junction box on the motor. I think the 98 model has this box. I know my 99 model does. There are terminal strips in their and the wires have come loose on mine cause inflammation weird things to happen. This is where the fuel rail solenoid relay is as well as all the interface wires that go to the engine. Sound to me like a bad ground or short.

Good luck.

Pete
 
This incident happened only 1time. Only the PORT motor shut down after the oil pressure light came on. Both motors run perfect at start up and on plane. It's just when I come off of plane the PORT side oil pressure gauge goes to max reading. The oil pressure light only came on once and the motor shut down (safety). When I go back on the throttle the oil pressure gauge comes down to a NORMAL reading. I believe it's a grounding issue, either on the sending unit or the oil pressure gauge on the dash. If if was failure, the gauge wouldn't read at all. I'm looking for other possible answers if I am wrong. Thanks to everyone who has answered and who is still thinking of other possibilities.
 
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Odd the engine shut down and an alarm was sounding in conjunction with a high gauge reading. The systems monitor and alarm have a separate and independent oil pressure switch on the engine which upon low oil pressure will provide the signal for the systems monitor to alarm. The oil pressure gauge has an oil pressure sender/dashpot which is mounted on the side of the engine. The gauge and sender wire is light blue and the system monitor and switch has a blue wire. What is common to these two items? Not much.. And what is common to bringing the throttle back to idle to cause the alarm and high gauge reading? Even less. The only thing I can think of is part of the wire harness is interfering with the throttle mechanism and shorting... Maybe check under the helm where the throttle mechanism is.
I will check connection on Thursday Morning
 
I would check that all is right with the world inside the junction box on the motor. I think the 98 model has this box. I know my 99 model does. There are terminal strips in their and the wires have come loose on mine cause inflammation weird things to happen. This is where the fuel rail solenoid relay is as well as all the interface wires that go to the engine. Sound to me like a bad ground or short.

Good luck.

Pete
It does have the box. I will check all connection Thursday morning. Looking for all possibilities.
 
I think about the only thing that can cause the engine to shut down, other than the obvious mechanical or electrical failures, is the halon system. If the halon system gets a discharge (fire) signal, it will shut everything down. Try disengaging the halon system on the dash it this happens again and see if it has any effect. IN the meantime, check the wiring for the halon system and see if you see a loose connection or perhaps a butt splice that needs to be cut out and replaced.
Frank, I will do this after I check my grounds. The port oil pressure gauge started bouncing at a high Max reading after coming off a plane, it was really weird. After about 10 minutes of idling I heard the ignition alarm sounding and when I look down the motor shut itself off. The oil pressure light was also on at the same time it shut off. I restarted the motor right away in the oil pressure came back to normal. That's when I drop the anchor, shut both motors off and went into the engine room.
 
Good morning. Checked every connection twice. Behind the gauges, behind the throttle cables, the Halo system, electrical cox on the back of the motor all the way to the oil pressure . I did tighten the nut on the single blue wire to the oil pressure sender in the block. Turned key and went all day. Gauge still reads above normal during cruising, when I bring back down to idle, pressure gauge goes to 100. I believe it's the oil pressure sender on the block, the resistance I being messed up for the dash gauge to accurately display it. I'm hoping to ordering 1 today.
 
There is an electrical connector that is located next to the transmission in that wire harness and close to where the large grounds are bolted to the gear.
This electrical connector can have corrosion issues as it is not the hermetically sealed type. The plus 12 volt (large red 10ga wire) and instruments to through that connector. If the pins and sockets are corroded who knows what can happen. Take that thing apart and clean it then liberally coat with di-electric grease and put back together. This is that connector (note - this cut from the SR Owners manual does not show the later junction box on the back of the CAT 3116TA which has additional slave solenoids for starter and fuel):
PortengWireHarness.jpg
 
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Bought a new sender today at my local CAT dealer. They had 1 in stock for $68. I will make the swap on Thursday when I have more time that afternoon. I am hoping it's the sender. If not I will dive back into the connections. I'll keep everyone posted. Thank you.
 
There is an electrical connector that is located next to the transmission in that wire harness and close to where the large grounds are bolted to the gear.
This electrical connector can have corrosion issues as it is not the hermetically sealed type. The plus 12 volt (large red 10ga wire) and instruments to through that connector. If the pins and sockets are corroded who knows what can happen. Take that thing apart and clean it then liberally coat with di-electric grease and put back together. This is that connector (note - this cut from the SR Owners manual does not show the later junction box on the back of the CAT 3116TA which has additional slave solenoids for starter and fuel):
View attachment 50781
I will definitely take a look at that ASAP. I will keep posting what the bug is. Thank you.
 
F1C884AA-9EEA-407C-9276-E3A16282DAC9.jpeg
7F16438F-DCEC-41B0-A7EC-EBBC7E01A794.jpeg
Made a call to Treasure Island Marina. Talk to John who talked with me about my ‘issue’ I was having. He ran a few senarios by me and we nailed the problem down. Within a week I had my ‘new gauge’. Apparently the gauge does not come from CATERPILLAR, it’s a 3rd part supplier for Sea Ray ( Thanks Frank Webster). Everything is back to normal. The oil pressure sender was getting bad. Here are a couple of pics. Gauge on port side is reading normal now. It was erratic during idle.
 

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