Nistune Forums

I'm having issues with my tune after installing my new turbonetics topmount turbo. the maf is as far away from the turbo as i can get it which is about 15 inches away theres only one bend in the pipe and thats only a slight bend right at the end of the pipe where it meets the turbo inlet. ive noticed when i have my headlights on my AF ratio changes and once in a while when on decel my wideband will read as if the engine is still under load instead of 3 dashes in red like it usually does on decel ive adjusted latency and my multiplier to get my tune close as possible for a streetable car till i get on the dyno. the car doesnt want to idle sometimes either. if i suddenly push the clutch in the engine will want to stall even if im just coasting to a stop and push the clutch in sometimes it will shut off.
any advice on how to go about diagnosing this issue would be great
Kyle

The timing set right? TPS set right? did u hit the burn to rom button when you were done?

My tune was perfect till I put the top mount on I did nothing with timing or tps and yes i hit the burn to rom.

I can see one problem from your photo - atmospheric venting BOV. Plumb it back to the pipe between AFM and turbo. Close to turbo if possible, and angle the pipe towards the turbo so that return air doesn't affect the AFM.

AFR changes when headlights are on sounds like a grounding problem. Check that grounds from battery > engine > chassis are secure and check the two ground lugs towards the rear of the inlet manifold.

Do a log in NIStune and check what your 12V is doing when you turn headlights on. It should sit between 13 and 14V and shouldn't vary more than about 0.25V.

PL

ok i will recirculate the bov when i get the parts to do so. what do you suggest i do about the vent for the valve cover right now i just have the hose that was on there from factory for the time being. should i just put a breather/filter on it or should i route it into the intake pipe in front of the turbo as well?

From memory that one doesn't go between AFM and turbo. It goes pre-AFM. But that's bad cos it'll dirty your sensing element.

Just put a filter on it or better a catch can.

PL

it should be routed back in behind the maf.

PL wrote:From memory that one doesn't go between AFM and turbo. It goes pre-AFM. But that's bad cos it'll dirty your sensing element.

Just put a filter on it or better a catch can.

PL

You sure mate? The air has already been metered, and the ECU knows it's there, so if you dump it back in before the MAF and it goes through again the ECU will think it's getting more air than it really is, because the previously metered air is being metered again.

All turbo applications I have seen have the BOV dumping back into the intake between the MAF and the turbo, or between the turbo and the inlet manifold, never dumping it back before the MAF, always after.

check the pcv valve in the rocker cover (top left in your picture) its a one way valve which can leak.
it doesnt matter to much when the other rocker cover pipes are in the right places but one of yours isnt plumbed back into the turbo inlet after the maf

so if the pcv one way valve is leaking (shouldnt be able to blow into the rocker cover) you'll be leaking boost straight through the rocker cover and into the atmosphere via the pipe not connected to the turbo inlet, effectively a boost leak and vac leak on idle

Would it really be a boost leak? I havent had any issues under boost my AF ratio is right on it's just when I idle its lean. Normal driving is ok too just my idle is leaner than I think it should be. Im going to move my ground wire for my maf and see if it changes anything when I turn the headlights on.

on idle the pcv valve is sucking crankcase pressure from the rocker cover into the inlet manifold but you have left a rocker cover pipe open to atmosphere hense causing a unmetered air leak and probably your lean idle

"noticed when i have my headlights on my AF ratio changes and once in a while when on decel my wideband will read as if the engine is still under load instead of 3 dashes in red like it usually does on decel"

Is it possible it's a issue with your WBo2 electrical grounding?
Maybe you knocked the ground loose or something when you were putting the new turbo in?

Ok so I'll go over my grounds and figure out a way to recirculate my bov and see what that does. Thanks for all the input it's been real headache before the tuning even began.

Hey HermaN,

We're talking 2 different things here. Yes, BOV has to go back post AFM. PCV goes back to manifold in the std configuration but lots of guys put catch cans on them to avoid having oily air ingested back into engine.

PL

Yeah I had to read that one twice! So PL referring to the PCV post MAF