06 apex mpi supercharger need help

[crowncokeandsoda]

OK, Here is the story. I just bought this used and it is my first boosted sled. Day 1 in West Yellowstone the sled runs great until we get up to about 7500 feet then it sputters a bit around 6000 rpm but pulls hard at WOT. Day 2 starts perfect at 6700 feet again untill we climb up a bit. then it cuts in and out from 6000 to 8000 rpm but idles fine and WOT is good. come down in elevation and it starts to work again. Day 3 starts good but up at 8000 feet it won't even idle any more. need to go half throttle to start it. At WOT the lights on my contoller all go red. back off a bit and they all turn green. Where do I start? I am running about 7 pounds of boost.

I know nothing about these things so too many abreviations will just create more questions

Thanks for any help.

 

[tko47]

may sound dumb but I had the same stumbling problem at midrange, so I put in new spark plugs and it fixed it , I was looking for evrything else vacuum leaks ,settings etc. spent hours dinking with it 20 bucks and 15 minutes was all it was!

 

[Wakegod]

What elevation was the sled setup for when you bought it? What are your fuel controller settings?

Search for "Hammer" on this section of the site and you will find tons of info.

 

[crowncokeandsoda]

Hmmm... it would have been set up for Sicamous/Revelstoke area. But it was in West Yellowstone last year and ran fine. controller was at 2,4,4,4,2,7 and I messed with them .5 to 1 whole number either way. I rode it in sicamous at new years and it ran fine.

 

[venom]

if it's the gems controller with the latest ver.13 it is very sensitive to altitude change.change alt mode to a lower # like 2/3/4.

 

[crowncokeandsoda]

is this the gems? is alt the last number?

thanks

 

[venom]

it might be but it looks like the old one.when i sent my fuel cont. back to mpi to get the latest version 13 they sent me a different one.the gems controller with G E M S written across the front.

GEMS controller settings for 5 to 8000ft
mpi stage 1 /apex 10lbs 50/50 mix no headshim.
modes and possible settings
1...idle/pilot 3-4
2...needle 4
3...main 3-5 depending on temp
4...boost fuel adder 4-5
5...accelarator pump 2
6...altitude comp 2-3