RX DI Cut off Relay + battery run-down issue.

[davemath]

I have just acquired a 2003 RX, my first foray into fuel injection as I always had early-mid 90's models for the past couple decades. I'm excited for the larger jet pump and the smooth power delivery.

The last mechanic of this cut the black/purple wire right outside of the rear coil box, then grounded that to the battery. This gave the cut off relay (2011 date code) constant ground, and therefore kept the ski powered on and would run his battery down. To solve this problem he put a high current physical power switch on the red battery line. He could have just put a small amperage switch on that black wire, and used the relay to handle this... But I digress.

I traced out the black/purple wire from that rear harness to the plug #3 and we have continuity on that wire.

From reading in the forums, this tells me that the MPEM may be bad; as my DESS peg and start-stop switch are working.

Is there anything that you guys note which could be a rogue component in this scenario? I re-seated and dielectric greased the AMP connectors everywhere, but haven't taken the MPEM apart to see if there is corrosion. I figure that I should let that stay waterproof!

Dave

 

[etemplet]

I've been getting more involved with the electronics on the skis and doing some research, reading, and on the job learning. LOL It makes sense grounding that wire if you don't want to replace the MPEM. The way the MPEM controls is by.... "switching the ground." I agree the guy could have put a small switch on the dash or somewhere. It would have been a convenient OFF/ON switch. Not for my taste though but hey... it works. Cool that you found that !! Good work !!

 

[davemath]

True, but financially I think the $5 waterproof switch in the glove box makes sense vs $250 for an unknown eBay or $500 for a tested/programmed MPEM!

Next up is sanding the hull with 3000 grit paper to find the red beneath the UV damage.

 

[etemplet]

Oh hell no !!! Start with 1000 grit. I didn't even use 1500. Went straight with the Meguire's heavy cut the lightly with the Polishing compound. I don't like wasting time on that crap. Looks good enough for me. LOL Good Luck !!

 

[GGuillot]

Next up is sanding the hull with 3000 grit paper to find the red beneath the UV damage.

Start way lower....unless you want to take forever start wet sanding. Go with 400 grit then work back up to 1500 or 2000 grit before polish phase.

 

[mikidymac]

400 is pretty agressive but I don't know how bad your finish is. On all of mine that were super bad I started with 800 then went up. For ones that are oxidized but not horrible you can start buffing with oxidation remover and avoid the sanding. You aren't trying to get down orange peel, just removing the oxidation.

 

[davemath]

Wow @etemplet - that tail end looks great and shiny!

I did a test run with removing his stickers and doing the 3000 grit, and it looks good on those rails. The front end may need the 1500 or lower. I think his cover disintegrated.

I found not one, but three black widow spiders on the ski in the last few days. It's me vs them now!

Put her in the water today and she wouldn't idle. I think the RAVE rebuild is next - I cleaned what was inside, but that wasn't a deep enough dive I assume....

 

[etemplet]

I'd pull out the BENGAL roach spray on those Black Widows. It'll get em' !!

Did you get it up to speed?

 

[mikidymac]

Dirty RAVES will not affect idle.

And good job with the 3,000 as you want to use the littlest grit needed to clean it up since you are removing some of the gelcoat thickness.

 

[noviceskier]

When I did my HX I wetsanded with 1500 grit up to 3000, takes time but don't see the need for removing that much material when doing it. Cut and buff with a wool pad to get a better finish faster, followed it with some polish on a polishing pad then used some meguiars wax to help keep my finish.

 

[mikidymac]

If you want to save the decals buffing is the easiest just don’t use too aggressive of a compound.

 

[davemath]

Thanks for the sandpaper tips team! Ok, got the old oil evacuated, new fuel pump installed and cleaned the RAVE valves...

Started her up and it would idle then clank - idle then clank, randomly and sporadically. Turns out that the PTO side piston has a bent ring, that was banging on that RAVE valve... I took apart the RAVE system and looked inside and saw a hole in the piston along the side vs the top. Something I've never seen before!

There was also a chip on the edge of the piston top, so whatever got inside that RAVE edge did some good damage. No "popcorn" marks on the top of the piston, from something bouncing on that however...

I'm going to look in to a SBT or WSM top end kit - the motor has 247 hours on it and I broke the paint studs on the head, so time for new guts!

Should I replace crank bearings while it is going to be open? What do you guys recommend at 250 hours?

 

[GGuillot]

Started her up and it would idle then clank - idle then clank, randomly and sporadically. Turns out that the PTO side piston has a bent ring, that was banging on that RAVE valve... I took apart the RAVE system and looked inside and saw a hole in the piston along the side vs the top. Something I've never seen before!

I found the side hole on one of the pistons on my first ski, 97' GTX, result of exactly as you describe the RAVE valve catching the rings and rubbing against the piston. It had an overbore rebuild in it and I don't think they trimmed the RAVE valves.

Unfortunately, you're probably going to need an entire engine rebuild, not just a top end. If that 247 hours is accurate, the crankshaft is not far behind from failing. You can't just replace the bearings on it, an economical approach could be doing a reman core swap on the crankshaft. SBT is pretty good about it, prompt on shipping and easy on the core return.

 

[mikidymac]

Replace the crank and get a rebuilt balancer shaft.

 

[mikidymac]

A 951 crankshaft is already a ticking time bomb on a good day. Almost none of them are known to survive a new top end. The odds are heavily stacked against you.

 

[etemplet]

Should I replace crank bearings while it is going to be open? What do you guys recommend at 250 hours?

People treat these engines ugly. Normally if the crank feels good I run it but... Considering the hours of abuse it probably took I'm with Miki on this one. Do the full Monty.