Mods are in the sig. I also installed a set of 1.6 roller rockers. After I did that, the motor stars backfiring and falling flat at high RPMs (5000+). I've tried everything from jets to ignition components. What I'm thinking is that I have a problem with the bowls running out of fuel.

I used to have a TPI system on my car, so I have a factory in-take fuel pump running fuel through stock lines and into a regulator to bring it down to 7 PSI for the carb.

Do you think this is a fuel pump or a fuel line (size) problem, or possibly both?

Thanks in advance.

 

did you just do these engine upgrades or did this just start happening.

 

This started happening immediately after the installation of the 1.6 rockers. Everything else was already done and I hadn't noticed the problem.

 

Too much preload on the lifters. Back the rockers off and reset the lash. 1/2 to 2/3 turn after 0 lash. I assume this is a hydralic roller?

Also assuming your springs can handle an extra .030-.040 of lift without floating the valves....