Boosted apex 260 mcx woes

I think my sled has a similar system, Its a 06 with the older mcx kit on it, It came with some switch in the back you'd flip, and no altitude compensation.


That being said, Do you have a boost gauge, Boost controller, Air fuel ratio gauge? if not I'd recommend to have the boost gauge and air fuel. When I bought my sled I never had the boost gauge and came to learn my sled never adjusted boost and I was under powered and running super rich at altitude, apparently It sort of fuels a baseline amount of fuel??? and so you'd turn up the boost to correct the a/f to what it should be, thus the a/f gauge comes to play.

My first issue with my sled was a weird popping and boost issues the odd time and at higher elevation mainly, My sled had a Aftermarket walbro fuel pump mounted under my intercooler as well as the in tank pump. I never knew what It was until I installed an a/f gauge to find out it went super lean like out of range, 20:1+ bad. Well It appeared the in tank pump system failed, the pump was fine but the pump in the tank pumps into some cartridge which I'd imagine must filter the fuel...??? well It must of got plugged. So I deleted the in tank system and ran a straight little fuel hose in there and left the job to the external pump, which Is a walbro gsl392, super high fuel flow rate and can suck the fuel just fine (and it does)

Also whether your sled has a external fuel filter installed or not? I installed one my self when I deleted the in tank pump, but It could be plugged if it does have 1.

So I'm not sure if this info helps much or not or what but do let me know!

vmax6 said:

Hey guys, I thought I would ask for some advise to those knowlegable with the fueling system.
My sled seems to be having an issue with altitude compensation? It runs fine from 1200- 25oo ft then gets to a point where its not taking fuel at 8- 9 K rpm. As I say, I am getting full boost and full rpm in the lower valley, but not up top. i will be checking for any cracked hoses in the system shortly.
Thx

Click to expand...

you need to descibe what its doing in a bit more detail,is it back firing,is it bogging or dying,is it not making boost at altutude or rpm.

woes

check the exhaust for leaks.

Just wanted to update as well from my previous post, I found my turbo wastegate to be seized solid from rusting in place I guess... So I sprayed penetrating fluid on it and took some pliers, worked some life back into it, It was stuck slightly open so I think lower elevation it ran better than up high due to air pressure difference