Hey does anyone have an idea why my car would drop from12.8 psi to 9, then go back up within a 1000rpm range (from around 5k - 6krpm) This is right around vtec engagement. My plugs are all gaped to .028 (ngkbkr7e)
When i rev the car out through that rpm range it back fires, sometimes really bad, but not always.
a little background:
ls/vtec
stock ignition
tuned on crome

thanks for any help

 

psi drop sounds like a boost controller or wastegate. Backfire sounds like fuel or ignition (tune). Eliminate what you know is good. When did it start, did it do it while you were being tuned?

 

it happened while we were tuning. It was really bad at first, but once we changed the plug gap it got alot better. I think its backfiring because of the sudden change in pressure. Does it sound like it could be a ignition problem? The reason i dont think its boost controller/ wastegate is because the pressure goes back up after 6000rpm

 

Yeah, sounds like ignition ot me. I've never had ignition problems so I'm not sure what you should replace first... Coil, I know ignitors on Hondas tend to go bad.

 

thanks, i'll start replacing stuff and see what happens

 

Same thing was happening on my car until my ignitor finally quit and i replaced it

vtec FTW

 

yea ingition problems