Over the last few months I have made several posts about the problems we have been having with our newer 2013 4.3 MPI throwing a false “Low Sea Pump Pressure” code and sending the engine into Guardian mode. We have been back and forth to the shop (under warranty) and it seems that Mercruiser, as well as the mechanic, are at a loss as to what to do next. You can see my last post here:
http://forums.iboats.com/forum/engi...iser-4-3-mpi-with-more-issues?_=1404657073423
On our last outing, the boat ran fine for a couple of hours but then once again we got the dreaded continuous alarm with the accompanying Guardian mode and restricted power. When I brought the boat back to the shop and they plugged in the computer, it once again showed the “Low Sea Pump Pressure” code had thrown but the pressure, as per the ECU, was 35 psi at 4800 rpms and coolant temp of 164 degrees. Per Mercruiser and the shop, this is an abnormally high pressure reading and that is why the alarm went off because the ECU saw the reading as Out-Of-Range high. So, Mercruiser instructed them to change the sensor, again. Firstly, is this possible that the alarm for low water pressure will activate if it sees an abnormally high water pressure? I thought that’s what the “Sea Pump CKT Hi” alarm was for, to indicate that the sensor reading was out-of-range indicating either a sensor failure or wiring trouble. Mercruiser did say that they think that the high reading was not accurate because that would indicate a coolant blockage downstream of the sensor which would cause an overheat situation, which did not happen. What do ya’ll think?
Now, I had read in some older posts that it WAS possible to bypass this pressure sensor. Some members had commented that, “…a trip to Radio Shack and a soldering iron…” could get the sensor bypassed, but did not go into any detail as to how that process would work. I am assuming that we would need to wire in some resistors in the sensor wiring to fool the ECU to think that the water pressure was good but I am not sure as to what resistance that sweet spot is. If anyone knows what resistance to dial this in at to make the ECU happy, please give me some help here. Also, I am assuming the gray wire is the ground so the resistors would have to go in between the other two wires, correct? Even though the boat and engine are under warranty for a few more years, I’m just ready to do this mod and be able to enjoy our boat by bypassing the sensor and installing a mechanical water pressure gauge at the helm to keep an eye on the water pressure.
I hate to have to take these measures and If any of you have any other ideas as to what to have them check, I’m all ears! It just seems as though both Mercuiser and the shop don’t really know what else to do next, and that’s really aggravating with a new boat. Below is a list of the things that have been so far to fix the problem to no avail:
Thanks for reading the lengthy post and I look forward to hearing from you all!
Have a great Sunday!!!
http://forums.iboats.com/forum/engi...iser-4-3-mpi-with-more-issues?_=1404657073423
On our last outing, the boat ran fine for a couple of hours but then once again we got the dreaded continuous alarm with the accompanying Guardian mode and restricted power. When I brought the boat back to the shop and they plugged in the computer, it once again showed the “Low Sea Pump Pressure” code had thrown but the pressure, as per the ECU, was 35 psi at 4800 rpms and coolant temp of 164 degrees. Per Mercruiser and the shop, this is an abnormally high pressure reading and that is why the alarm went off because the ECU saw the reading as Out-Of-Range high. So, Mercruiser instructed them to change the sensor, again. Firstly, is this possible that the alarm for low water pressure will activate if it sees an abnormally high water pressure? I thought that’s what the “Sea Pump CKT Hi” alarm was for, to indicate that the sensor reading was out-of-range indicating either a sensor failure or wiring trouble. Mercruiser did say that they think that the high reading was not accurate because that would indicate a coolant blockage downstream of the sensor which would cause an overheat situation, which did not happen. What do ya’ll think?
Now, I had read in some older posts that it WAS possible to bypass this pressure sensor. Some members had commented that, “…a trip to Radio Shack and a soldering iron…” could get the sensor bypassed, but did not go into any detail as to how that process would work. I am assuming that we would need to wire in some resistors in the sensor wiring to fool the ECU to think that the water pressure was good but I am not sure as to what resistance that sweet spot is. If anyone knows what resistance to dial this in at to make the ECU happy, please give me some help here. Also, I am assuming the gray wire is the ground so the resistors would have to go in between the other two wires, correct? Even though the boat and engine are under warranty for a few more years, I’m just ready to do this mod and be able to enjoy our boat by bypassing the sensor and installing a mechanical water pressure gauge at the helm to keep an eye on the water pressure.
I hate to have to take these measures and If any of you have any other ideas as to what to have them check, I’m all ears! It just seems as though both Mercuiser and the shop don’t really know what else to do next, and that’s really aggravating with a new boat. Below is a list of the things that have been so far to fix the problem to no avail:
- Change water pressure sensor
- Change thermostat and check poppit valve
- Change Sea Water Pump in lower unit
- Reflash ECU with updated software
- Check wiring for abrasions, cuts, kinks, or other damage
- Change water pressure sensor, AGAIN!
Thanks for reading the lengthy post and I look forward to hearing from you all!
Have a great Sunday!!!