Alpine nytro runs rough past 3000 rpm

[Boostednytro09]

Took my nytro out today to try it out and once it’s about 4500 rpm it runs bad and will not increase rpm at all, has good compression. When this happens the afr Gauge starts reading very lean. Any info? Thanks

 

[Riley Cloarec]

Check fuel filter pickup etc. Check fuel pressure. If those don't fix maybe injectors.

 

[Boostednytro09]

Check fuel filter pickup etc. Check fuel pressure. If those don't fix maybe injectors.

I have changed fuel filter, I’m leaning towards a fuel pressure issue now, it runs very well idling but once it starts making boost it just cuts out and stumbles but doesn’t die

 

[Riley Cloarec]

Not sure how the alpine works does it use extra injectors? If so maybe the boost vacume lines need to be checked make sure its sending boost signal to boost controller to turn on injectors.

 

[Boostednytro09]

Not sure how the alpine works does it use extra injectors? If so maybe the boost vacume lines need to be checked make sure its sending boost signal to boost controller to turn on injectors.

It does run extra injectors and I checked all the lines I could find and didn’t have any cracks or leaks that I could find

 

[Riley Cloarec]

Could be your regulator not rising as it boosts ?

 

[Boostednytro09]

Could be your regulator not rising as it boosts ?

Where would this be, I’m new to this sled and I have had nothing but problems trying to get it going for winter lol

 

[Riley Cloarec]

Does it run external fuel pump and regulator or just stock fuel pump. 240 and down can run off stock pump. 270 up is external. Mine is mcx and sits in front of intercooler

 

[Boostednytro09]

I believe it has a external pump under intercooler, it’s a 270 kit so I would think it has one and am pretty sure it does.[/QUOTE]

 

[Riley Cloarec]

Yea so you'll have a rising rate fuel pressure regulator. Google malpassi rising rate regulator to see what it looks like. It runs a boost line to it so when it sees boost it sends more fuel for extra injectors.

 

[ClutchMaster]

I would suspect the Hobbs switch that turns on under boost. First check fuse for your external pump tho.

 

[Boostednytro09]

I would suspect the Hobbs switch that turns on under boost. First check fuse for your external pump tho.

I’m sorry I am new to this sled, what is a Hobbs switch, also I have just noticed that my primary clutch has some big grooves in it. Could this be causing the sled to possibly redline? And for the tach not to register as it climbs to quickly

 

[OZ_8721]

Bottom line is sled is losing fuel. I'm not familiar with the Alpine kits but you need to check the external fuel pump, regulator, etc and make sure each is working. Renting a fuel pressure gauge from the local auto parts store will help a lot.

I had this same problem with my MCX 270 all last winter, the secondary injectors weren't firing. Finally turned to be either a bad chassis ground for the MCX fuel controller or a bad ground at the extra injectors. I'm leaning toward chassis ground in my situation because I had to replace the steering gate with a used one at the beginning of the season (thats where the chassis ground for the controller goes) and it didn't work after that. The bad ground also ruined (I suspect) my fuel controller because I sent it on to be checked and it was bad. So I had a problem on top of a problem.

 

[Boostednytro09]

Bottom line is sled is losing fuel. I'm not familiar with the Alpine kits but you need to check the external fuel pump, regulator, etc and make sure each is working. Renting a fuel pressure gauge from the local auto parts store will help a lot.

I had this same problem with my MCX 270 all last winter, the secondary injectors weren't firing. Finally turned to be either a bad chassis ground for the MCX fuel controller or a bad ground at the extra injectors. I'm leaning toward chassis ground in my situation because I had to replace the steering gate with a used one at the beginning of the season (thats where the chassis ground for the controller goes) and it didn't work after that. The bad ground also ruined (I suspect) my fuel controller because I sent it on to be checked and it was bad. So I had a problem on top of a problem.

I tore into it a bit more and found that the secondary injectors are not firing at all, fuel pressure is good, it has power to the injectors but they aren’t firing, do injectors get stuck closed? The sled sat with fuel in it for a couple years maybe they are clogged?

 

[Mountaintech]

What controls the injectors? Not familiar with the Alpine system.