Hey guys, I have a friend with a 99' Prelude with a JG Pro Series head. His VTEC is not engaging smoothly and his car is misfiring lightly at Idle. When we hit VTEC, right around 6000RPM it hesitate and it feels like sometimes the VTEC kicks in and sometimes it kicks out. He also has a VTEC controller. I checked everything in the VAFC and nothing's wrong with it. We checked the Ignition, plugs and wires, checked for any leaks in the vaccuum line and everything is fine. Anyone here know what could be wrong or any suggestion on what to check for next? We're in the process of elimination right now so we're checking everything and anything that might be the cause of this.

ps: Anyone have experience with JG pro head? Any comments or suggestion will be appreciated. Thank you.........

 

Whats the stats on the compression of that head on your car and are you sure its
timed right?

 

Same thing happened to my car. I took it in, and they said everything was okay. So about 3 weeks later, it just started to work again on its own. I may take awhile for it to work again like it should. I drove my car like that for only about a month or so.

 

Tell this guy to check his oil level asap. Vtec will do this when your oil pressure isn't high enough. I've expierenced it first hand, like i said i'm glad i use mobil 1.

 

We just changed the oil in his Car so the Oil Level is good. We also use Mobile 1 in our Preludes!!! Well.......right now I am thinking that its his VAFC that is messing up his VTEC engagement. Tomorrow I will take out his ECU and check for any miswire or any short in his ECU. His engine is also not holding Idle and dies everytime we rev it up. Ever since he had his JG head installed he's had problems with the car. Well......thanks for your help guys, I really appreciate it!!!

 

good luck!