High rpm/boost misfire

[MSP2003.5_Nick]

So anyway couple days ago I was enjoying a country road drive and went to hit some boost and it sputtered a bit. Did it again and it was fine. Next day went out and it wasnt just sputtering, it was bucking and misfiring and making all sorts of racket in full boost. I can rev to any rpm with no issue and hit up to 10 psi no problem but past that up to 22psi in WOT at any rpm and it happens.

FYI dont tell me its egr or maf or any crap like that cause I dont have it. Running full stand alone haltech sport 1000 with dyno tune and its been perfect for a month since I brought it back out for the season.

I went ahead and bought new plugs, wires and coil pack since I've never replaced coils or wires anyway thought it was time. Gapped to .028 running stage colder ngks. This had no affect still same issue.

Then I checked all my vacuum lines and they`re all good. Checked fuel rail pressure and its 45psi at idle just what it should be.

The other thing I thought it could be was boost cut, so I went into the haltech and disabled it but still same problem.

Just want people to throw out suggestions to help me figure this out. AFR is 11.7 at full boost and when it sputters it jumps lean.

 

[Silverspeed2015]

ive been having a similair problem but mine sputters in vac also, the car threw a CEL code was PO340 "Camshaft Position Sensor Circuit Malfunction" im going to see if its the camshaft sensor.

 

[MSP2003.5_Nick]

I miss my check engine light so much easier to diagnose.

 

[Silverspeed2015]

lol, i cleared mine but it still runs like crap so im hoping the camshaft sensor fixes my problem

 

[MSP2003.5_Nick]

did some more testing of sensors and they all check fine. The only thing i could think of to cause it would be insufficient battery voltage to keep up with high rpm full boost spark and fuel demands. Checked the battery voltage with car off and it's 12.2v which is great. Started the car and measured alternator charge voltage and it's 13.1v It's supposed to be 14.5 or so.

I'm thinking my alternator is crapping out and cant keep up. After all I'm using the stock alternator with a standalone using hall affect signal to the ecu. Maybe without the reluctor signal the ecu is suppose to have it's not controlling the alternator correctly and causing pre-mature failure.

I'm gonna get my hands on a 626 IR alternator and see if I can at least get a good charging voltage if not fix my issue at the same time.

 

[HKPRO5]

^^^ Any updates?

 

[kamon8404]

I thought that the alt is supposed to put out between 13-14vt when on?

 

[hornsfan10609]

My battery voltage gauge reads 13.5-13.9v, rarely gets up to 14.

 

[MSP2003.5_Nick]

Had nothing to do with voltage. It was actually a piece of my piston that was flying around and kept destroying the plug. The piston finally detonated completely a week after my first post. Motor is at the shop getting a new sleeve put in.

 

[Silverspeed2015]

that sucks, my problem was a broken timing belt tensioner spring