I'm having problems with my ls vtec turbo, too rich at idle 10.0 afr's. If i create a vacuum leak it get much better 12.5 - 13.0 , Normally this car idle 14.5 to 15.0

The car is a relic from 2010.
Ls/vtec piston/rod
b16 head, GSR cams, supertech spring & ret.
750cc inj.
crome pro/ tuned
Removed FPR hose and no gas (AEM FPR) so no broken diaphragm.

No CEL, no codes. If i remove any vacuum hose it get better and to 1.5K RPM. I remember to read somewhere about Bypass getting to close or open at idle due to wear and changing the air intake at idle.

Any Help, Thanks

 

do a complete tune up:
VALVE LASH ADJUSTMENT
ngk plugs
ngk wires
cap and rotor
fuel filter
air filter
oil change
check/adjust ignition timing with a timing light.

if after you do ALL of the above it still runs stupid rich, you either need a retune, or you need to get the engine's health checked out by a professional

 

I already perform almost everything in the list, less timing check, oil (1K old) and turbo air filter.

If timing check and filter removed, not fix it, maybe it's time for a retune and new software system. Neptune seem's pretty user friendly and good price.

 

Is this the first time you run this engine? Was it running well and suddenly the A/F ratios just went rich? I ask as if this is the first time the engine is running it is probably a tuning issue. If it was running fine and it suddenly went rich then the tune is probably not the issue. If it suddenly went rich, first remove the plugs one by one and check them. See if they are all rich (would be sooty black insulators) or only one or two are rich. If only one or two are rich then you have an issue with those specific cylinders. Check those specific cylinders, change plugs first, and see if that fixes the issue. If not go down the line, injectors, wires, cap etc.. If ALL your plugs are rich check that you have adequate spark, if spark checks out good and is not weak, check your ignition timing, if that is also good then you have too much fuel. Check fuel pressure first, if it is withing range then you probably have a tuning issue.

 

No, the engine has almost 6 years but weekend use only, and yes it happen suddenly.

I already replaced, Cap, rotor (OEM) wires NGK and plugs BKR7E11 at .0025 Today I'm going to run it and read the plugs after let it idle a for a while.

 

what rpm is the car idling at? are you sure the wideband sensor didnt go out showing incorrect AFR?

 

When I broke the ring lands on #3 my AFR's went into the 10's at idle.