Hey guys, I have a 99 ls1 stock motor with a huron v1 kit, racetronix 340 pump with regulator and return, with 80lb injectors. Running 8lb wastegate spring. Car ran great for 100 miles, and then lost almost all power on a 2nd gear pull as soon as I got into boost. Drove fine other than that, replaced plugs, wires, and crank sensor. Same issue, seems to be just hesitating in 3rd gear at 4k rpm. Last night, it sat for 15 minutes after it acted up and then would not start at all. Ate dinner, and it started fine. 60 psi at the fuel rail, and pump is working fine. Air fuels are good until it misfires. No dtcs, and does not act up when revving in park. Any ideas? I have attached a log.

 

Did you change dwell settings when you went the boost direction? What spark gap you running?

 

The car was tuned by a very reputable dyno shop .028 gap, worth mentioned it ran great for awhile before I bought new and properly gapped the plugs. I’m leaning towards a coil ?

 

update : tuner said it’s losing fuel pressure under boost .

 

Are you logging fuel pressure?

 

No. this is what he said. I replaced the regulator and fuel filter. I’m trying to get a gauge to read while I’m driving . I’m guessing a defective 340 pump or a cracked Intank line.

 

no way i'd rely on narrowband sensors to tell me its going lean/rich. you need a wideband, ive seen it be pig rich but show lean on a narrowband. if its pig rich, it will cut out too.

 

a $20 transducer in the shraeder valve wired to the factory EGR pintle position is a cheap, easy, and effective way to log fuel pressure. Can make it a T to put a real gauge on it too if desired.

 

Sorry I forgot to mention, I have a wide band and it is going lean when it falls on it’s face. But I also know a misfire will read lean. So I want to confirm with a fpg.

 

Are your talking about the shraeder on the end of the fuel rail? If so my regulator is plumbed into this.

 

If your tuner is talking about narrowband readings when tuning for boost... his opinion suddenly matters a lot less.
Make sure your wideband is pinned into the ECU, as well as a fuel pressure sensor. Log them both along side the other engine parameters.

 

I'd still like to know the dwell settings. To be fine under no load and acting up under load sure sounds like it's possibly blowing the spark out.

 

FWIW, I've never touched coil dwell up to 750whp and never had an issue. Usually if its misfiring under boost the AFR is too rich or the plug gap is too wide......or weak coils.

OP- can you post some pics of the plugs? What plugs are you running?