Thank you for all the ideas GoBig. I will start working down your list to see if I can find any issues.
bottom end bog fix?
- Thread starter MikeM1000
- Start date
G
Gobig510
Well-known member
Pipe Sensor
I'm no expert, but to me it seems like the pipe sensor is the boss. If it is telling the ECU that you are way too rich, it won't matter how much fuel you try to add with a box, the ECU is going to listen to the pipe sensor... I might be totally wrong in that assumption, but it seems like you could possibly have a bad pipe sensor, telling your ECU you are running too rich, the ECU pulls the fuel way back (that's when you see the full lean and bog) and doesn't listen to your box... Or that is completely wrong and you have something else going on entirely! That's the way it is with these things, but at least for $30, a pipe sensor might be a good thing to rule out...
I'm no expert, but to me it seems like the pipe sensor is the boss. If it is telling the ECU that you are way too rich, it won't matter how much fuel you try to add with a box, the ECU is going to listen to the pipe sensor... I might be totally wrong in that assumption, but it seems like you could possibly have a bad pipe sensor, telling your ECU you are running too rich, the ECU pulls the fuel way back (that's when you see the full lean and bog) and doesn't listen to your box... Or that is completely wrong and you have something else going on entirely! That's the way it is with these things, but at least for $30, a pipe sensor might be a good thing to rule out...
Spent some time looking things over today since I had to replace reeds anyhow.
Last ride out my sled nstantly dropped the PTO cylinder and I hade to be towed home. The bottom reeds on the PTO side had sheared off all four screws and the reeds, stops and four screw heads were just laying there. One of the reeds had lost an entire petal and it was nowhere to be found. I have no idea how they sheared. They only thing I can come up with is that I over tightened the screws and they started to twist off then let all the way go. I don’t think I can get the broken screws out so I am on the hunt for new cages. The good news is the reeds weren’t too bad other than that. One small chip on the bottom reed on the top but it was still sealing The mag side had a tiny chip on one but still working good. This is not my low end bog though as I have had it with good reeds.
I checked my power valves and the cables. The PTO cable is nearly worn through and measured 35.5 mm and the mag side was 33.6 They are supposed to be 35 and within .5 of each other. I corrected the mag side to 35and will order a new PTO cable tomorrow.
I noticed when I first got this sled that there was a small screw in the gas cap vent hole plugging it. I never thought much of it until I started trying to figure out what is causing my low end bog. I looked the gas tank over and found a vent line near the top of the tank with a 6” hose attached to it that pointed to the steering post and a one way valve in the end of it. I blew and sucked on the valve and could get NO air to pass through at all. I then went to remove my gas cap and as soon as I loosened it, it released quite a bit of air pressure. Keep in mind I have not rode the sled in a week. It either held that pressure that long or possibly built some pressure this morning when I heated the garage up to work on it. I find nothing in the instructions that mention the vent line or plugging the cap. My stock sled does not appear to have the vent hose and uses the same cap but with no screw plugging the vent hole. This strikes me as odd. Anyone have thoughts on this?
I also checked and found no problems with:
The movement of the power valves (cleaned them any how)
Baro tube
ADA sensor
Various turbo related wiring
Primary spring is not broken, but it is an unmarked black spring so no idea what it is.
Last ride out my sled nstantly dropped the PTO cylinder and I hade to be towed home. The bottom reeds on the PTO side had sheared off all four screws and the reeds, stops and four screw heads were just laying there. One of the reeds had lost an entire petal and it was nowhere to be found. I have no idea how they sheared. They only thing I can come up with is that I over tightened the screws and they started to twist off then let all the way go. I don’t think I can get the broken screws out so I am on the hunt for new cages. The good news is the reeds weren’t too bad other than that. One small chip on the bottom reed on the top but it was still sealing The mag side had a tiny chip on one but still working good. This is not my low end bog though as I have had it with good reeds.
I checked my power valves and the cables. The PTO cable is nearly worn through and measured 35.5 mm and the mag side was 33.6 They are supposed to be 35 and within .5 of each other. I corrected the mag side to 35and will order a new PTO cable tomorrow.
I noticed when I first got this sled that there was a small screw in the gas cap vent hole plugging it. I never thought much of it until I started trying to figure out what is causing my low end bog. I looked the gas tank over and found a vent line near the top of the tank with a 6” hose attached to it that pointed to the steering post and a one way valve in the end of it. I blew and sucked on the valve and could get NO air to pass through at all. I then went to remove my gas cap and as soon as I loosened it, it released quite a bit of air pressure. Keep in mind I have not rode the sled in a week. It either held that pressure that long or possibly built some pressure this morning when I heated the garage up to work on it. I find nothing in the instructions that mention the vent line or plugging the cap. My stock sled does not appear to have the vent hose and uses the same cap but with no screw plugging the vent hole. This strikes me as odd. Anyone have thoughts on this?
I also checked and found no problems with:
The movement of the power valves (cleaned them any how)
Baro tube
ADA sensor
Various turbo related wiring
Primary spring is not broken, but it is an unmarked black spring so no idea what it is.
S
Sno Junkie
Active member
How many people with the bog have a tunnel dump exhaust? Mine does the exact same thing in the deep powder. My A/F guage goes full lean. I believe it is a rich condition that is killing the motor. It was brought to my attention that maybe in the deep powder the tunnel dump exhaust is having some restriction when you stop?
M
MarleneeSteven
Well-known member
Mine did the exact same thing, but I don't remember what fixed it because I've had to replace so much chit in the last six months.
I want to say it was the diamond drive that was the culprit of that particular problem, but I'm not for sure.
I want to say it was the diamond drive that was the culprit of that particular problem, but I'm not for sure.
If you think about it ....
You're adding a major restriction to your air intake and exhaust @ low RPMS vs. where you were stock, primarily to your air intake with the turbo and IC being there. With that being said, you need less fuel with less air. Watch your tachometer as your throttle it from a dead stop ....
On my 09' 800, I wound up going -5 @ 3,000 RPM -10 @ 5,000 rpm .... I was leary at first about taking that much out of it, but after paying very close attention to my EGT's I was comfortable with it, and its run MUCH better ever since. You don't get in any trouble at all taking that much fuel out of the bottom end while you're accelerating, because you rarley ride your sled @ 5,000 rpm and your turbo will spool right around there too so as soon as that happens you're on Lo Boost setting .... I had pretty good luck doing this with mine, but where you can get in trouble and _NEED_ to pay attention to your EGT's .... when you're coming down a hill and the sled is revved to 4500,5500 rpm with no load ..... I never saw my EGT's get over 900 or so with these settings which is fine, but that was 300 higher than with the stock settings .....
Either way, my sled is running WAY better overall taking that much fuel outta the bottom end.
The other thing I did to it this season was to put the Thunder Products 911 clutch cover on. It doesn't seem like it would do much, but it makes clutch engagement much smoother and on a turbo sled that helps quite a bit.
Hope this helps.
M
MarleneeSteven
Well-known member
If it's the same thing....as I said above, one day, my M8turbo just started dying as soon as I got out in the powder. I would have to get off and push to get it to start moving, and once I did, it would run fine.
I took it in to the shop and the following had went bad, so I'd check each:
Diamond Drive ate the planetary
regulator went bad
rectifier went bad
I had two fuel pumps, in line, and the second one had went bad
stator went bad
As soon as I fixed these items it was better. Now, it certainly doesn't run like a stocker in the low end, but at least I don't have to push!
I took it in to the shop and the following had went bad, so I'd check each:
Diamond Drive ate the planetary
regulator went bad
rectifier went bad
I had two fuel pumps, in line, and the second one had went bad
stator went bad
As soon as I fixed these items it was better. Now, it certainly doesn't run like a stocker in the low end, but at least I don't have to push!
S
Sno Junkie
Active member
Check out my post in cold air intakes.... http://www.snowestonline.com/forum/showthread.php?t=294277
It helped the bottom end of my sled tremendously.
It helped the bottom end of my sled tremendously.
WOW its like a crap shoot.
Bottom end issues. Over fueling, Clutching or reads 99% of the time.
First is reeds if it starts good all the time then not reeds.
If you have the right clutching a proven setup.
Then it fuel. When you put a turbo on it restricts the air from start until turbo starts to flow thus needs less fuel. So if you have a BD box you lean the 3000 and 5000 low # for example on a 07-09 it would look like this
3000 -4 -2 0
5000 -2 0 0
On a 2010-12 its leaner look like this
3000 -10 -5 0
5000 -5 -3 0
Then when you have a Attitude,Pure Logic,Push or the Dolbek box on a cat the do not have the ability to minus fuel. So that is why you have to turn your fuel pressure down to as low as 28Lb to try and get the bottom end to work. The problem with this is the lower you go the less fuel pressure you will have at boost.
All the rest of the issues that were brought yes can happen and you should look at them if you had a bottom end at first. On the HO motor the lower compression head does soften your bottom end up a bit.
Hope this helps.
http://www.snowestonline.com/forum/showthread.php?t=301986
Bottom end issues. Over fueling, Clutching or reads 99% of the time.
First is reeds if it starts good all the time then not reeds.
If you have the right clutching a proven setup.
Then it fuel. When you put a turbo on it restricts the air from start until turbo starts to flow thus needs less fuel. So if you have a BD box you lean the 3000 and 5000 low # for example on a 07-09 it would look like this
3000 -4 -2 0
5000 -2 0 0
On a 2010-12 its leaner look like this
3000 -10 -5 0
5000 -5 -3 0
Then when you have a Attitude,Pure Logic,Push or the Dolbek box on a cat the do not have the ability to minus fuel. So that is why you have to turn your fuel pressure down to as low as 28Lb to try and get the bottom end to work. The problem with this is the lower you go the less fuel pressure you will have at boost.
All the rest of the issues that were brought yes can happen and you should look at them if you had a bottom end at first. On the HO motor the lower compression head does soften your bottom end up a bit.
Hope this helps.
http://www.snowestonline.com/forum/showthread.php?t=301986
A
akholland
Member
steady fuel pressure
So in this post you said something about having steady fuel pressure. What type of guage were you using? I'm having the same issue with this guy with the bog thing. My fuel pressure is 45psi at idle but the needle is vibrating at a high frequency between like 42 and 48. off idle it smoothes out a little bit but still the needle vibrates between 49 and 51psi. Is this normal for a bd pump with the AC to DC booster hooked up? does the bd pump just not hold stead pressure correctly?
So in this post you said something about having steady fuel pressure. What type of guage were you using? I'm having the same issue with this guy with the bog thing. My fuel pressure is 45psi at idle but the needle is vibrating at a high frequency between like 42 and 48. off idle it smoothes out a little bit but still the needle vibrates between 49 and 51psi. Is this normal for a bd pump with the AC to DC booster hooked up? does the bd pump just not hold stead pressure correctly?
I have 09 tm8, the other day after a long pull, i would let off the throttle it sounded like it would run on one cylinder, if you pin it it would be fine. The weather out was hot and if i let it set for a while it was fine, once i did another long pull it would do it again. The reeds are good, the sled does not have a cold air intake, would to much under hood heat do this. Any thoughts to solve the problem would be great help.
