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Low Oil Pressure on 5.7 with 210 hours

J

jbltimes3

New member
Oil Pressure alarm periodically goes off when engine is at idle and in gear. Replaced oil sending unit on back of block (total pain to do) and have changed oil from 10w/30w synthetic to the factory recommended 30w synthetic. Boat is a 2002 with 210 hours - bought boat new and have changed oil/filter every year. No abuse (senior citizen owner!). Used for pulling grandkids on tube and cocktail cruises. Alarm issue just started last year and is not consistent. Any suggestions on how to address the issue and silence alarm?
 
I had a similar problem with my 2001 FourWinns with a 4.3L. My symptoms were the same, and I was never convinced that there was actually a low-pressure issue, just that the monitoring systems were detecting one. I did the same things you did (replaced the sending unit - twice with a Volvo part, once with a GM automotive part, changed the oil from 10w-30 back to 30), each time I'd convince myself that I had fixed it. But it kept recurring. I plumbed in a mechanical gauge to confirm my suspicion that this was an electrical problem. That was easy, and the gauge cost about $10 from Autozone. But even though I knew this was an electrical problem and not a real oil pressure problem, every time that dash alarm sounded it put my stomach in knots.

On the 4.3L and the 5.7L, there are 2 parallel systems for the oil pressure. One system runs the gauge on the dash and a dash alarm (lighted oil can and audible beep.) The other system sets a much louder alarm in the engine compartment when the sustained oil pressure drops below 4psi (this one also sounds when the ignition is turned to "on" but before the engine is started.) After several hours of boating, my gauge would jump all over the place, and the dash alarm would sound. Never did the simpler system in the engine compartment sound an alarm. It turns out that the problem was in the dashboard. The dash was an automotive type made by VDO (a division of Siemens), as opposed to separate marine gauges. After doing my research, it turns out this was a well-documented problem with VDO dashboards of this era. The fix that worked for me was to run another grounding wire from the dash. Others have addressed this by buying separate gauges and building a new dashboard.

If you have a dash made by VDO, I can send you some information from them including a wiring diagram that will help you find a suitable spot to attach an additional ground wire. I was able to do it with a screw that was already in place, and didn't need to do any soldering.

Good luck,

Craig
 
I have also had a similar problem with my oil pressure gauge in the dash along with a lower reading my RPM gauge. I have a 2001 5.7L and according to the Four Winns site both are VDO gauges. Would this grounding also address my problem? What exactly needs to be done?
 
Craig, thanks for your reply....can you forward me the information on where I can get the wiring diagram...I will try adding the ground wire vs screwing up my dashboard...I REALLY appreciate your reply and hope this fixes the problem.
 
I can't figure out how to up-load the pdf. PM me or post an e-mail, and I can send it to you directly.

As I said in my original post, I was able to connect a new ground wire to the only screw on the back of the cluster (after testing it to be sure it was connected to Ground), so the hardest part was running a wire to the engine. For that, I used a fish-tape and pulled the wire.

Good luck.

Craig
 
craigo said:
I can't figure out how to up-load the pdf. PM me or post an e-mail, and I can send it to you directly.

As I said in my original post, I was able to connect a new ground wire to the only screw on the back of the cluster (after testing it to be sure it was connected to Ground), so the hardest part was running a wire to the engine. For that, I used a fish-tape and pulled the wire.

Good luck.

Craig
Click to expand...

I think I found the PDF file on the VDO website - PDF 0-515-012-123 ...I have it printed out..if you can give me the PDF file number, I can probably run it down (assuming it is not the one I already have).. my email is [email protected] ..thanks again for your help.
 
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