Couldn't decide if this should go here or in the external section so apologies if its in the wrong place. Several of my friends and I have been banging our heads against the wall trying to figure out what is wrong with my friend's car. The car is a 2000 TA and it has an ls3 stroked to a 416 in it. We're running the motor with the 2000 computer. The car previously had the same block in LS3 form and ran fine. Car has ported L92 heads with a custom cam, I don't know the cam specs. We believe it is on 11.3 compression. The problem is that under full throttle the car will not pull past 5800. It runs fine up until that point, then cuts out, backfires and dies. The tune is spot on, our tuner was able to tune it. The VE table is good and the AFR is spot on 12.98 all the way up until 5800 when it dies. It then goes to 19.0 AFR and backfires. We've done a crank relearn and the car is tuned speed density. We're currently at a loss. Like I said, it ran fine when it was a LS3, and the only change was a rotating assembly. Has anybody got an idea what it may be? We're about ready to burn the thing lol. Thanks in advance for any info.

 

check the fuel pressure ?

 

Gonna check it tomorrow to make sure but we haven't checked it so far because the AFR is perfect right up until the cut out event. Its an instantaneous cut in power. We can't tell if we're losing fuel or spark its so quick.

 

What size injectors is he running? Do you know what duty cycle they are maxing out at? It sounds like his injectors are too small..... check fuel pressure like said, and injector duty cycle....they shouldnt hit anymore than 85%

 

Sounds tuning related

 

He's running 42 lb injectors. Gonna check fuel pressure when he gets off work. We're wondering if something is not right with the crank sensor or the reluctor wheel. We had trouble with it when we first put it in. At first it was only firing on 5 cylinders. Changed to a new crank sensor and it fired on all 8. Thanks for the responses.

 

One of my friends had his reluctor wheels touching and the car ran great till he would try and go wot...it would rev to a point ( wheelie from a launch) perfect, then hit a certain rpm, POP and shut off. They should be gasped at .040"