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Another 800etec down and out.

7K views 42 replies 15 participants last post by  DTXRSB 
#1 ·
Hey guys, been a long time since i posted on here. Used to be mostly active on the older S-chassis forums, For a brief while a stepped up to a '07 MXZ with the 800 powertek, And now im here!

Anyways only a few short weeks ago after lurking on here and reading up on the 800 Etec's, i pulled the trigger on a very nice and clean 2014 Renegade Backcountry 800x with 7600km's on the clock. Honestly it's the first sled I really been attached to since selling my 1998 Mxz 670 9 years ago. After reading a few threads and seeing how some fella's have been betting 10k+ km's on these engines I figured I would get a couple years from this one till it would need some maintenance.

Unfortunately I was wrong, yesterday the engine decided to seize on me in the middle of a lake (just taking my time, not at WOT) Should have picked up on it, because leading up to it the signs were all there that it was slowing dying. Oh well. Today I pulled the engine, have yet to pull the head but with a glance through the exhaust ports I can see it melted the mag side piston as well as ruined the RAVE valve on that side.

At 7700 km's on the bottom end and due to not having the time nor a garage of my own to rebuild this engine myself sensibly, Im leaning toward a new short block. I will be tearing into this engine to figure out what exactly caused this, My main concern is the fuel injectors, since this is my first time dealing with a ETEC engine. Can they be tested to see if they were the cause of the failure? Can I buy used ones if needed? Also what other tips and trick can you guys give me for re-assembly as far as bleeding the oil pump etc, etc. Any improvements I can make while its gutted?

It seems I have bought myself a moneypit, but oh well :wacko: I'll keep this thread updated as I tear down the engine in the upcoming week. Thanks in advance!

Mark
 

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#6 ·
Could you describe the events leading up to it seizing?
First thing i noticed was hard starting (in the cold) but i never paid any attention to this considering the temps here were around -30c where I'm living.

Next was the engine not firing when being put into RER, noticed that about 20 mins prior to and also noticed it idling a little low (800rpm or so vs the usual 1050rpm) Otherwise it never went down on one cyl at any point, it just point blank died in the middle of the lake.

Another thing i noticed that day (and it maybe unrelated) was my battery not charging (a brand new battery,) electrically everything else was working fine, just got me wondering if maybe something happened to the stator and possibly took out a crank seal on that side maybe.

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#8 · (Edited by Moderator)
The piston looks like it ran remarkably lean. I think your thought on getting the injectors flow tested is a good idea. Take your time prior to tearing into the engine to get everything you need from it. Make sure to identify each component to know which cylinder they belong to, especially the spark plugs and head o-rings. Take one plug out and mark it right away because they tend to get mixed up.
 
#10 ·
I've got a 2016 800 etec I've had since new. Last year at the end of the season at 13,000 miles PTO side melted down. Under warranty thank goodness. Turns out the stator did fail and the mechanic described to me the ECM dumps power from the two good coils into that circuit and causes the injector to malfunction. I've got two thousand miles on the replacement motor and stator and it's running perfect. No injector work at all. I was concerned the injector was going to malfunction due to this electrical problem but it is good. It did cause my ECM also to have a problem with the temperature reading out digitally and they had to replace the ECM. Don't mean to scare you this is what I've had.
 
#12 · (Edited by Moderator)
It sounds like the stator was going.
I'm not sure what was up there, i put a new battery in the day before because the old one just had it with the temps we have been having here in Labrador City. Started fine for a while and afterwards nothing. I will be testing the stator once its out.

There's no doubt it ran lean, surprised me a bit cause the mag side plug wouldn't really white, it did have a slightly grey tinge to it but at first glance i don't think would of called it lean. The PTO side was burning perfect.
(Mag plug on the left.)
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#13 ·
I'm not sure what was up there, i put a new battery in the day before because the old one just had it with the temps we have been having here in Labrador City. Started fine for a while and afterwards nothing. I will be testing the stator once its out.

There's no doubt it ran lean, surprised me a bit cause the mag side plug wouldn't really white, it did have a slightly grey tinge to it but at first glance i don't think would of called it lean. The PTO side was burning perfect.
(Mag plug on the left.)

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I never like seeing a grey tinge on a plug. Being in Labrador City you guys tend to be self sufficient when it comes to diagnosing and fixing things that would normally be sent to shops. Do you still have a local guy that fixes pretty much everything from autos to microwaves to sleds?
 
#14 · (Edited by Moderator)
I never like seeing a grey tinge on a plug. Being in Labrador City you guys tend to be self sufficient when it comes to diagnosing and fixing things that would normally be sent to shops. Do you still have a local guy that fixes pretty much everything from autos to microwaves to sleds?
There is a local dealership here, but Im a Journeyman heavy equipment mechanic myself, this is the first sled engine i have had stripped now in a few years! But im no stranger to it, this is the first ETEC i have touched . But I know a thing or two [emoji23]

Tonight i got it stripped down to the cases at least, MAG side piston is melted as seen before, monoblock is toast, mag side rave valve got slightly snagged by the melted slug. The magneto is still on, but the crank will does not seem to rotate freely at all, Im expecting to find bad crank bearing(s.) The good news is the head is untouched and still in good shape, the reeds/boots all check out fine too. I was figuring the head would be hashed from pieces of ring flying around.

Im starting to think of another theory that possibly the stator was ok and it was charging, but the starter couldn't crank it over with the stiff crank and the piston starting to carve into the cyl. leading up to this. Tomorrow i will get the stator out (needed a puller) and split the cases if needed
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#18 ·
My guess is the injector on that side or the ECM which told the injection to spray less on that side. Guessing here.
I'm really hoping the injector is the cause of all this, heading to the dealership tomorrow to look into getting the injectors checked out and get a quote on a shortblock… It just blows having to deal with this just weeks after buying this thing.
 
#19 ·
I have the same sled with about 4300 miles and now wonder about an EGT guage....
It's a nice tool to see if one side is hotter than the other. If can be anything from the reed boot, ring, injector, primary guillotine and even coolant ingestion from a head o-ring leak. If not used well it can lead to an anxiety disorder lol
 
#20 ·
There is a local dealership here, but Im a Journeyman heavy equipment mechanic myself, this is the first sled engine i have had stripped now in a few years! But im no stranger to it, this is the first ETEC i have touched . But I know a thing or two [emoji23]

Tonight i got it stripped down to the cases at least, MAG side piston is melted as seen before, monoblock is toast, mag side rave valve got slightly snagged by the melted slug. The magneto is still on, but the crank will does not seem to rotate freely at all, Im expecting to find bad crank bearing(s.) The good news is the head is untouched and still in good shape, the reeds/boots all check out fine too. I was figuring the head would be hashed from pieces of ring flying around.

Im starting to think of another theory that possibly the stator was ok and it was charging, but the starter couldn't crank it over with the stiff crank and the piston starting to carve into the cyl. leading up to this. Tomorrow i will get the stator out (needed a puller) and split the cases if needed

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It looks like the piston ring land squeezed the ring. Did the exhaust bridge crack? If not then you may get away with a hone, two new pistons and a crankshaft. Who knows how far the aluminum and metal shavings reached into the rod bearings, and you'll probably won't like the sound of the center bearings. You can forget the other piston with 7600km on it.

And by a hone, I do mean a professional type hone that you would have sent to CV Tech or St-Pierre moteur. If they need to remove too much material then you can try forged pistons. Or better yet just get a shortblock from your local dealer. I know you were thinking of a shortblock, so I am just working it through because with labor this repair will reach near the market value of the 6 yrl sled in running order. So while you are at the dealer, see how far the total cost of repair will get you a sled under warranty. Then add the money from selling the sled as is. There is at least a couple thousand dollars left in your sled.
 
#21 · (Edited by Moderator)
It looks like the piston ring land squeezed the ring. Did the exhaust bridge crack? If not then you may get away with a hone, two new pistons and a crankshaft. Who knows how far the aluminum and metal shavings reached into the rod bearings, and you'll probably won't like the sound of the center bearings. You can forget the other piston with 7600km on it.

And by a hone, I do mean a professional type hone that you would have sent to CV Tech or St-Pierre moteur. If they need to remove too much material then you can try forged pistons. Or better yet just get a shortblock from your local dealer. I know you were thinking of a shortblock, so I am just working it through because with labor this repair will reach near the market value of the 6 yrl sled in running order. So while you are at the dealer, see how far the total cost of repair will get you a sled under warranty. Then add the money from selling the sled as is. There is at least a couple thousand dollars left in your sled.
I won't be getting rid of the sled after just getting it. Despite all this the sled is in great shape otherwise.

Spent yesterday removing the stator and water pump housing and checking everything over. After taking a closer look i noticed the locator pin on the mag side piston has backed out, allowing that ring to spin and hook in the exhaust port.. I'm just surprised there was no damage to the head. But im figuring this was likely due to this cyl running lean. Otherwise i can't find any other obvious problems. Oiling ports are all clear, oil lines had oil. Reed petals and boots are in great shape, no cracks in the boots. Whats your thoughts Daag?
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#22 ·
Buddies 16 just blew
2000 miles.

First ride. Topped it off with fresh fuel. Ran all day friday
Sat overnight cold. In morning would not start. Jumped it and started right up

1 mile down trail. Down

At dealer now but they said one cylinder o psi.

Gotta assume water in fuel and or iced injector
 
#23 · (Edited by Moderator)
I won't be getting rid of the sled after just getting it. Despite all this the sled is in great shape otherwise.

Spent yesterday removing the stator and water pump housing and checking everything over. After taking a closer look i noticed the locator pin on the mag side piston has backed out, allowing that ring to spin and hook in the exhaust port.. I'm just surprised there was no damage to the head. But im figuring this was likely due to this cyl running lean. Otherwise i can't find any other obvious problems. Oiling ports are all clear, oil lines had oil. Reed petals and boots are in great shape, no cracks in the boots. Whats your thoughts Daag?
31d1287728ba95594d04dae9dbaf2555.jpg
b409551d70c30583a56014342902cf2d.jpg
e51b4b9f9597a01a61a39932148298b6.jpg
a2a4aefdde95835a41ad25d49353029f.jpg


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Exhaust side overheats for long periods leading to light deto that hammers and melts the rings lands. The section that is hit the hardest weakens and squeezes the ring tight. For the the ring to run true to the cylinder it needs to move freely in the piston lands as the piston changes from thrust to compression. Once the ring gets pinched/stuck in one position, two things start to happen. The first is excessive blow-by during compression that breaks the oil film on the exhaust side. The second is the ring looses its shape and forced to grow oblong leaving the opposite side unsealed and blow-by breaking down the oil film.
 
#24 ·
Just a quick update, i have a shortblock ordered. The dealer here is allowing me 6 months warranty on the engine installing it myself. I have a nearly new set of injectors ordered for piece of mind and will be having the sled set to break in mode when its up and running again.

Hopefully i should have everything to reassemble the sled within the next 2 weeks or so, so we'll see how it goes!

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#25 ·
Just a quick update, i have a shortblock ordered. The dealer here is allowing me 6 months warranty on the engine installing it myself. I have a nearly new set of injectors ordered for piece of mind and will be having the sled set to break in mode when its up and running again.

Hopefully i should have everything to reassemble the sled within the next 2 weeks or so, so we'll see how it goes!

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You have to sync those new injectors with the ecu using buds.
 
#26 ·
Good to hear, curious with my our 14 gsx 800r having 7500 miles on her but sled is well takin care of and like new cosmetically i would most def throw a short blcok in her when she goes What did u pay for short block and what of ur won aled do u combine to make complete engine? Good luck and keep the updates coming
 
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