Bent Valve cause misfiring?!
 

I just went to get my crx smogged with stock D15 engine and it didnt pass. The guy told me that HCM is high because due to bent valve and that it is misfiring is some rpm. Then it dawn on me. I overheated my engine a while back and i changed the headgasket and i only got the head resurface but i didnt get a valve job because i thought it wasnt worth paying $250 more for a D15 engine. So what would you guys suggest?

Re: Bent Valve cause misfiring?!
 

buy another head ;)

Re: Bent Valve cause misfiring?!
 

but bent valve cause higher HCM? Thats unheard of....

Re: Bent Valve cause misfiring?!
 

unburnt gases flowing out the exhaust instead of being trapped in the cylinder and burning

Re: Bent Valve cause misfiring?!
 

WTF is HCM? I think you mean HC (hydrocarbons). And yes that would cause misfiring because that valve is putting raw fuel into your exhaust stream

Re: Bent Valve cause misfiring?!
 

do a leakdown test.

Re: Bent Valve cause misfiring?!
 

i always wonder whats the difference between a leakdown test and a compression test?

Re: Bent Valve cause misfiring?!
 

a leakdown test determines how well the valves and rings hold the pressure.

Re: Bent Valve cause misfiring?!
 

They're completely different, the only similar thing is you put stuff in the spark plug hole for both tests ;)

Leakdown you shoot compressed air into the cylinder when it's at TDC on the correct stroke and measure what % of air is leaking out.

Re: Bent Valve cause misfiring?!
 

yep..and alotof ppl dont give importance to leakdown test.. :3 ..

Re: Bent Valve cause misfiring?!
 

so i cant use my compression tester? ---- the car stutters alot when im driving it. This suppose to be my daily driver too.

Re: Bent Valve cause misfiring?!
 

no you need a leakdown tester.

or just a different head

Re: Bent Valve cause misfiring?!
 

You need to learn how to properly do a leakdown test. What gave you the idea it's almost the same as a compression test?

Giggity google it

Re: Bent Valve cause misfiring?!
 

Re: Bent Valve cause misfiring?!
 

Did someone ask what CO meant or something?

Re: Bent Valve cause misfiring?!
 

rich?.....fuel system?

Re: Bent Valve cause misfiring?!
 

Just be careful when doing a leakdown...I have a test kit that's a combo leakdown/compression tester, needed to do a leakdown and c/t on my subaru. Set the motor at tdc on cyl 1 (the cylinder I was testing), shot compressed air in, and almost got smacked in the face by my rachet that was still attached to a cam gear :1 I think I only shot about 60 psi into it, but I forgot to make sure the crank was immobile :l

Re: Bent Valve cause misfiring?!
 

and when you put it in gear to lock the crank, make sure the e-brake is on or whell is choked.

Parking a tire ontop of your buddys foot is funny.....but he wasn't laughing!

Re: Bent Valve cause misfiring?!
 

so having a high HC means that there are unburnt fuel? What would cause this though?

Re: Bent Valve cause misfiring?!
 

a misfire

Re: Bent Valve cause misfiring?!
 

but how? timing is not off.

Re: Bent Valve cause misfiring?!
 

doing a leakdown will help determine which cylinder and reveal either intake valves, exhaust valves or oil rings.

Re: Bent Valve cause misfiring?!
 

pull all 4 plugs and see if one of them is fouled worse then the others.