XR1800 4-Stroke MR1 Swap

[84rzv500r]

according to the print the blue wire goes from pin14 on the ecu to pin 18 on the security box... im guessing that its a pull down to enable the ecu... as without that I was getting no signal on the YDS... ill find out today...

 

[Robb235]

according to the print the blue wire goes from pin14 on the ecu to pin 18 on the security box... im guessing that its a pull down to enable the ecu... as without that I was getting no signal on the YDS... ill find out today...

So here’s a question for you. How is low wake mode activated within the jet ski ECU? Normally if the security box wasn’t disabled, it’s activated by holding the unlock button on the remote. The security box then puts the ECU into low wake mode.

So then how does the security box talk to the ECU? There’s only two wires that go from the security box to the ECU: the Yellow wire and the Blue wire. We already know that the yellow wire is for the main relay circuit. So that would leave the blue wire, right? I feel like that blue wire has got to be related to the low wake mode somehow.

 

[Robb235]

Water tested the boat this morning, and it mostly went well. The river was windy and choppy, so I didn’t test top speed. Easily hit 40mph on the GPS, then backed off due to the chop.

The starboard motor seems to have an uneven idle compared to the port motor; the starboard tach needle ‘bounces’ much more than the port one. While in the water, I used YDS to deactivate one cylinder at a time. When I deactivated cylinders #1, #2, and #4, it caused the motor to stop running (presumably because it was already running on three cylinders at idle). Deactivating cylinder #3 didn’t affect much, motor kept running. So this seems to point to an issue with cylinder #3. However while on the water, the starboard engine had no problem reaching 11k RPMs. So something seems to be going on with cylinder #3 at idle on the starboard motor.

Port motor ran flawlessly.

 

[84rzv500r]

starboard engine all hooked up... fuel pump relay working runs up to 50 PSI then shuts off with keys witch on, main relay working, crank no start... guessing no spark or no ECU... hooking up YDS

 

[84rzv500r]

no bueno... lights are on but no ones home.. gonna try port engine

 

[84rzv500r]

YDS says Port engine has a bad intake temp sensor or signal error... will diagnose, Starboard engine has no ECU comms, so its wiring harness or ECU.

I dont think I have a spare intake temp sensor (sensor assembly (MAP/Temp) but I have two known good ECU's. new sensor assemblys are are 200 days out from yamaha, I found a couple used ones on ebay... ill test the wiring and the sensor... for the ECU its easiest to swap it first.

 

[Robb235]

YDS says Port engine has a bad intake temp sensor or signal error... will diagnose, Starboard engine has no ECU comms, so its wiring harness or ECU.

I dont think I have a spare intake temp sensor (sensor assembly (MAP/Temp) but I have two known good ECU's. new sensor assemblys are are 200 days out from yamaha, I found a couple used ones on ebay... ill test the wiring and the sensor... for the ECU its easiest to swap it first.

For your port engine, you positive you didn’t forget to connect an electrical connector somewhere? Perhaps around the air box?

 

[84rzv500r]

I need to go into the airboxes again anyway to adjust WOT and the throttles I'll check the wiring... im guessing the sensor is really bad... i had a couple of broken sensors that I assembled into one good one. I checked everything i could during assembly even checking the thermostats opening... we'll see..

 

[Robb235]

Ok, somehow I’m killing multiple fuel pumps. When the starboard one died I just thought it was a fluke. Now my port one is dead. When I turn the key to ON, it sounds like it’s priming, but nothing is flowing through the fuel line. I pulled the fuel pump assembly partially out of the tank, and I can see that all of the fuel is flowing out of the pressure relief port, and nothing is flowing from the outlet nipple. Not sure if there is something I’m doing that’s killing them, or if they’re just a bad batch of pumps.

Fuel pump failure #2

youtube.com

Fuel pump failure #1

youtube.com

 

[84rzv500r]

hose collapse inside?

I have a spare OEM pump if you need it out of my donor ski...

 

[Robb235]

Think I found the problem. On another thread I have going, it was brought to my attention that I did not have an in-tank fuel pressure regulator installed. I mistakenly thought that these pump were internally regulated, but they are not. So basically I'm killing the pumps because I'm dead-heading them. I'm ordering a pair of in-tank regulators so that way I'm not burning through fuel pumps.

 

[84rzv500r]

Think I found the problem. On another thread I have going, it was brought to my attention that I did not have an in-tank fuel pressure regulator installed. I mistakenly thought that these pump were internally regulated, but they are not. So basically I'm killing the pumps because I'm dead-heading them. I'm ordering a pair of in-tank regulators so that way I'm not burning through fuel pumps.

ah makes sense. I went with walboro stainless continuous duty rated pumps they dont care wet or dry.. do have external regulators set at 48 PSI return lines to the tank...

 

[Robb235]

Going to try my hand at reupholstering my seats.

 

[Robb235]

The in-tank regulators didn’t work out, so I went with my single fuel pump feeding a dual outlet regulator, that then feeds both motors. This was the setup I originally planned to use, so I already had the parts. I have the regulator mounted on the fire wall, where you can see that my insulation is deteriorating.

 

[84rzv500r]

The in-tank regulators didn’t work out, so I went with my single fuel pump feeding a dual outlet regulator, that then feeds both motors. This was the setup I originally planned to use, so I already had the parts. I have the regulator mounted on the fire wall, where you can see that my insulation is deteriorating.

thats essentially the same regulator I have.... a 3/8 line should easily support your WOT of 26Gph and 320 HP. I have one for each side and they have to be restricted down to 5/16 anyway at the fuel rails...

 

[Robb235]

My first time reupholstering something.

 

[Robb235]

I salvaged the jet pumps and trim system controls from my donor jet skis. At this point, nothing useful remains, so now I need to find a place to scrap them, and sell the aluminum trailer.

I wonder if the pumps from the skis offer any improvement from the stock XR1800 jet pumps?

I’m also interested in trying to adapt the trim control systems to the boat. I would love to repurpose my now unused choke knobs and cables to be able to adjust trim on the jet pumps. It was done by a member on the other forum, and he reported back that trim made no difference on his XR. So maybe it’s not a project worth tackling. Unfortunately that member is no longer active, so I didn’t get to ask him how he has the trim controlled. Anyways, I won’t be attending the project anytime soon, I want to actually enjoy my boat this season.

 

[Robb235]

Replaced the spark plugs in the starboard motor and POOF, just like that, it idles as it should. Surprised they needed to be changed that quickly. I put fresh ones in two years ago when I started the engine swap, and have hardly ran the engines so far.

Anyways, starboard motor now has a constant overheat warning going off on the stock XR indicator, which is wired directly to the thermoswitches. The engine is dead cold, and the overheat alarm is constant with ignition on. So now that’ll be the next issue to investigate.

 

[Robb235]

Well, the overheat warning went away on its own. Not sure what that was about. Anyways, took the boat out for a test run Thursday evening as the sun was going down.

 

[Robb235]

Took the boat out this weekend to where my in-laws had their camper setup on the river. Put about 8 hours on the boat, went flawlessly up until the very end Sunday evening. Finished my last high speed turn, then throttled down, but the starboard engine hung right at 6k RPMs. I cut it off with the key, and every time I tried to restart it, it went right back to 6k. Luckily I was close to the dock, so I limped back on the port motor.

Haven’t had a chance to dig into it yet, but I’m curious what’s allowing the motor to spin up to 6k on its own. If the throttle is held open, the ECU will not allow that motor to start, yet I’m able to fire it up no problem. Will investigate this week to find out.