2006 apex. the thottle stays open for a couple seconds after letting off. No problems with the cable. just think the boost is holding open the blades for a second or two. why? I put a bosch pop off on and it didnt fix the problem. Do I need the mpi blow off to fix this problem?
Mavric
Newbie
- Joined
- Feb 2, 2006
- Messages
- 16
Maybe the boots either on the motor or
fuel injectors are not sealed or loose.
fuel injectors are not sealed or loose.
nate007
Lifetime Member
- Joined
- Dec 25, 2006
- Messages
- 2,770
- Location
- Iowa City, Iowa
- Country
- USA
- Snowmobile
- 1. '06 Apex -twin screw
2. '04 Redline Revolt 800
3. '09 Nytro XTX - twin screw
It depends what type of "pop off" valve you are using.
I have an HKS and it has a vacuum reference that tells it when to open, and it's 2 stage, so it will bleed off just a little when cruising around, or alot after a full throttle run. I use this type of set up on the street cars I build just because you're not always at full throttle, and if your valve is set to blow off just above your max boost it wont do much of anything unless you're letting off at max boost.
I've seen different "fixes" for this by bypassing TORS, modifying the return spring on the throttle bodies, and IMO, they're all just band-aids for teh real problem.
Post what your set up is, it's something that needs to be corrected asap! Having the throttle stay open in an emergency isnt good!
I have an HKS and it has a vacuum reference that tells it when to open, and it's 2 stage, so it will bleed off just a little when cruising around, or alot after a full throttle run. I use this type of set up on the street cars I build just because you're not always at full throttle, and if your valve is set to blow off just above your max boost it wont do much of anything unless you're letting off at max boost.
I've seen different "fixes" for this by bypassing TORS, modifying the return spring on the throttle bodies, and IMO, they're all just band-aids for teh real problem.
Post what your set up is, it's something that needs to be corrected asap! Having the throttle stay open in an emergency isnt good!
first real ride on the sled at elevation and the boost runon wasnt too bad but the fuel mileage was crap at 5 mpg. has to be because its boosting all the time. 8 psi even at a light cruise of 40 mph on the level
nate007
Lifetime Member
- Joined
- Dec 25, 2006
- Messages
- 2,770
- Location
- Iowa City, Iowa
- Country
- USA
- Snowmobile
- 1. '06 Apex -twin screw
2. '04 Redline Revolt 800
3. '09 Nytro XTX - twin screw
That's not great, but it doesn't sound like most are getting a whole lot better than 8. I haven't had enough miles on mine yet this season to tell.
Either way, you shouldn't have any boost run-on, so I'd dig into your valve and see if there's adjustments you can make there.
As far as the mileage, do you have a wideband? I know MPI says for 8 psi you don't need it, but it's great tuning tool and can probably help the mileage? There's a ton of different things that can affect that as well, just be sure to go over your machine frequently and stay on top of the mainainence. Every little bit helps.
Either way, you shouldn't have any boost run-on, so I'd dig into your valve and see if there's adjustments you can make there.
As far as the mileage, do you have a wideband? I know MPI says for 8 psi you don't need it, but it's great tuning tool and can probably help the mileage? There's a ton of different things that can affect that as well, just be sure to go over your machine frequently and stay on top of the mainainence. Every little bit helps.
talked to mpi today and they said their bypass valve would solve the boost runon and to tune the boost fuel mode on the gems to get better mileage.
nate007
Lifetime Member
- Joined
- Dec 25, 2006
- Messages
- 2,770
- Location
- Iowa City, Iowa
- Country
- USA
- Snowmobile
- 1. '06 Apex -twin screw
2. '04 Redline Revolt 800
3. '09 Nytro XTX - twin screw
Similar threads
