What's causing my exhaust valves to close?

[skibreeze]

Before I go tearing into the valves, I wanted some feedback. I'm having an issue where the valves open normally and then close while still WOT or close to it. Seems to be intermittent. So far there isn't any oily mess that would indicate a tear in the bellows.

 

[KAWGRN]

I thought the ecm controlled the solenoid valve which controlled the Valves??

 

[4Z]

Bad connection in the harness? If both are doing it at same time.

 

[sledneck_03]

try capping the barbs with vacuum caps and removing the Y pipe from the valves to the solenoid. friends 2011 solenoid failed.

 

[towny]

Cleaning power valves

This might help?

http://www.snowest.com/forum/showthread.php?t=345760

 

[AndrettiDog]

You run a turbo yes? Just tie them off and keep them open all the time.

 

[Boston Racing]

Its not that easy. If the valves open sooner than programed the sled will have a rich spot until the rpm where the valves should have opened. On SkiB's sled the vlaved open, shut, open, shut. Its the wierdest thing. He is changing the solenoid now.

 

[89sandman]

couldn't have anything to do with the turbo cause everyone knows that all turbo sleds are pull and go with no problems ever

 

[LoudHandle]

As mentioned in the $28 dollar upgrade thread, it may be due to temps as the ECU is programed to protect the engine at all costs. So if your temps get over 129 from memory it starts adding fuel and pulling timing. If it climbs further 132 it pulls even more timing and adds more fuel. If you are still not pulling R's because you are loosing power with each of the timing pulls, it closes the valves. May not apply in this case but worth mentioning.

Just what I remember reading. FWIW

 

[AndrettiDog]

Its not that easy. If the valves open sooner than programed the sled will have a rich spot until the rpm where the valves should have opened. On SkiB's sled the vlaved open, shut, open, shut. Its the wierdest thing. He is changing the solenoid now.

I thought since the turbo would be spooling he would be ok closing them off. Good to know, thanks for the info.

 

[diamonddave]

Before replacing the solenoid, test it with 12 volts and an air hose. I have seen 1 stick before and freed it up by spraying PB blaster and cycling the solenoid with a battery and 12 volts a few times. Still works to this day.

You could also pinch off the hose to verify the issue isn't mechanical with the valves themselves.

 

[skibreeze]

The first thing I did the other day when it started to run like crap was change the plugs with new iridiums and the symptoms did not change. We plugged off the exhaust valves and it ran better, but by no means alright. Next was checking and cleaning the power valves, a bit of carbon build up but expected at 850 miles. Swapped out a solenoid, since I had a spare sled to change it easily enough.

Today we had an identical sled and swapped ECUs, no change in symptoms. We put my plugs in the other sled and it ran fine, then put the other sled's plugs in mine and it ran right. I can't explain how my sled would run like crap with a set of plugs, but be fine in another sled. Pisses me off as this was the very first thing we changed the other day and it didn't fix the issue until yet another set of plugs was installed.

Thanks to Cory Boston and Next Level Power Sports for helping me get it figured out.

 

[BILTIT]

What was the plug gap on both sets of plugs?

 

[Boston Racing]

They were gapped correctly. Put a new set of reguilar plugs in at .018 and wallah. Mine started acting crazy with your Irridiums SkiB. I'm thinking there is something up with those plugs.

Oh, and we all know the white ones run better to start with