Viper sputters off idle.

[yamahajohnson220]

I've got a problem with my mpi turbo viper. It is the base kit with the electronic boost controller and filter outside the hood. If I'm at idle and crack the throttle to wide open the engine studders for about 1 second and primary will not engage. After that it takes off and runs nice and smooth through shift out. I ride at 10,000ft elevation on 100ll fuel. I have the ulmer high elevation clutch kit installed. Is this a fueling or clutching issue?

 

[turbo800]

Sounds like you need to put a AFR gauge on your sled. My guess, at that altitude, its rich and could use leaned out. Mine is pretty crisp for the most part. Its awesome knowing on the fly what the fueling is doing. I guess its no surprise mine runs well since I ride the same elevation as MPI and only 150 miles away.

 

[stingray719]

I've got a problem with my mpi turbo viper. It is the base kit with the electronic boost controller and filter outside the hood. If I'm at idle and crack the throttle to wide open the engine studders for about 1 second and primary will not engage. After that it takes off and runs nice and smooth through shift out. I ride at 10,000ft elevation on 100ll fuel. I have the ulmer high elevation clutch kit installed. Is this a fueling or clutching issue?

Does the primary actually engage or does the engine sputter so bad it does not engage? Clutch speed engagement please.

 

[yamahajohnson220]

Sounds like you need to put a AFR gauge on your sled. My guess, at that altitude, its rich and could use leaned out. Mine is pretty crisp for the most part. Its awesome knowing on the fly what the fueling is doing. I guess its no surprise mine runs well since I ride the same elevation as MPI and only 150 miles away.

I have the koso x2 installed and since its only about a full second studder, the gauge does not react fast enough to show me lean or rich.

 

[TRUEBLUEMAX]

I have the koso x2 installed and since its only about a full second studder, the gauge does not react fast enough to show me lean or rich.

I have the same x2 also. It has all the wow factor but response time is pretty slow.

I was having the same trouble with my nytro. Mine ended up being weights that were too heavy so it was having trouble getting going. Not sure if your problem is the same but that is the difficulty I was having.

 

[yamahajohnson220]

Does the primary actually engage or does the engine sputter so bad it does not engage? Clutch speed engagement please.

After a second look with the side cover off at my home which is sea level, the primary is engaged. I'm now thinking this is a fueling issue. Any thoughts greatly appreciated.

 

[stingray719]

After a second look with the side cover off at my home which is sea level, the primary is engaged. I'm now thinking this is a fueling issue. Any thoughts greatly appreciated.

As truebluemax has said if your engagement is not right you can have low rpm and the fuel programmer thinks it is already boosted and throws a bunch of fuel in. I have the edge programmer on my powerstroke truck and turned up I can blow a black cloud over an entire intersection for the same reason....lol...is especially funny if a convertible is tailgating me. Anyways, please make note of the actual rpm it engages and the top rpm from just rolling up to good speed (environment dictates that speed).

 

[seano700]

CO counts

The older nytro turbos had us messin with the CO's to clean up the bottom end. Can we do that on the viper, or has that been locked down?

 

[yamahajohnson220]

I'm sure it's not a clutching issue. This thing falls flat on its face and studders.

 

[BigFish BC]

I'm sure it's not a clutching issue. This thing falls flat on its face and studders.

make sure your boost signal line does not have a kink it will screw up your fueling if the box is not seeing boost fast enough.
could be your fuel box too,the dobec boxs have had allot of issues over the years.

 

[yamahajohnson220]

Sounds like you need to put a AFR gauge on your sled. My guess, at that altitude, its rich and could use leaned out. Mine is pretty crisp for the most part. Its awesome knowing on the fly what the fueling is doing. I guess its no surprise mine runs well since I ride the same elevation as MPI and only 150 miles away.

Forgot to update this post. Turbo800 you were correct. I leaned my fueling out back in November and I no longer have the studder as explained. Still leaks oil as usual. Oh well, at least for now my rods are holding in there even though I have a pos front end now.