Went out again this weekend after putting another set of plugs in (fourth set in 300 miles), decided to try a little hotter plug (didn’t work though).
Just to give a background, I’m fouling stock plugs CR9EB’s on one ride, and have even fouled an O2 sensor. When at idle through mid-range the sled runs EXTREMELY rich (wideband gauge reads 10.0) and WILL NOT run without feathering the throttle. This feels and acts much like being on full choke on a carbureted sled and is running so rich I burned through 16 gallons of fuel on a 68 mile ride.
I have taken the entire rail off and have checked all of the hoses for vacuum leaks and have glued and reset the throttle body boots. The only vacuum leak that is obvious is out of the bottom of the Idle Air control valve assembly. On the left side of the fuel rail there are two fittings about ½ inch in diameter that come out the front of the IAC. These run into two vacuum hoses that bend 90 degrees downward and go into a black plastic chamber that is zip-tied to the front of the fuel rail (this is right between the rail and the #1 intercooler boot). Then from the chamber is another single 90 degree vacuum tube that is vented to atmosphere (this used to be connected to the stock airbox, but was left open to air as per the MPI instructions for the supercharger and intercooler installation).
When doing a vacuum or a boost leak test air leaks through this port quite freely. When I start the sled and hold my finger over the open hose, it will stall the sled so I assume this is supposed to be open somewhat, but I’m not sure how much. I’ve asked the dealer about this being bad, and was told that they never go bad and if it did it would throw a code.
This is a problem from the “stock” side of my sled though. I have tried disconnecting the fuel controller and this still is happening. I have also noticed that when the presence of boost comes on and there isn’t any vacuum the AFR’s are perfect and the sled runs great.
Please help, this is getting EXTREMELY frustrating and we’re running out of riding days.
Thanks
Just to give a background, I’m fouling stock plugs CR9EB’s on one ride, and have even fouled an O2 sensor. When at idle through mid-range the sled runs EXTREMELY rich (wideband gauge reads 10.0) and WILL NOT run without feathering the throttle. This feels and acts much like being on full choke on a carbureted sled and is running so rich I burned through 16 gallons of fuel on a 68 mile ride.
I have taken the entire rail off and have checked all of the hoses for vacuum leaks and have glued and reset the throttle body boots. The only vacuum leak that is obvious is out of the bottom of the Idle Air control valve assembly. On the left side of the fuel rail there are two fittings about ½ inch in diameter that come out the front of the IAC. These run into two vacuum hoses that bend 90 degrees downward and go into a black plastic chamber that is zip-tied to the front of the fuel rail (this is right between the rail and the #1 intercooler boot). Then from the chamber is another single 90 degree vacuum tube that is vented to atmosphere (this used to be connected to the stock airbox, but was left open to air as per the MPI instructions for the supercharger and intercooler installation).
When doing a vacuum or a boost leak test air leaks through this port quite freely. When I start the sled and hold my finger over the open hose, it will stall the sled so I assume this is supposed to be open somewhat, but I’m not sure how much. I’ve asked the dealer about this being bad, and was told that they never go bad and if it did it would throw a code.
This is a problem from the “stock” side of my sled though. I have tried disconnecting the fuel controller and this still is happening. I have also noticed that when the presence of boost comes on and there isn’t any vacuum the AFR’s are perfect and the sled runs great.
Please help, this is getting EXTREMELY frustrating and we’re running out of riding days.
Thanks