jmille25

I just got through replacing a burnt exhaust value on a friends 2002 Honda Accord EX (2.3L)...however the car runs like rubbish. It's surging at idle.

So far I've...
- tripled checked the timing. It's spot on.
- performed a leak down test. 2.5% leak down on all cylinders.
- checked the timing with a timing light...and for whatever reason it's firing at TDC instead of BTDC.

I've also bled the cooling system and played around with disconnecting some of the sensors to see if it would make a difference...no luck. Also there is no CEL.

I'm out of ideas and a little bewildered. Any ideas or thoughts would be greatly appreciated.



MY THOUGHTS ON WHY THE EXHAUST VALVE FAILED...

When I took apart the intake, there was A LOT of carbon in there. My friend also told me that prior to the valve going, he replaced the EGR valve (which didn't work) and then had a mechanic clean the EGR port...it was totally clogged. So I'm thinking that a piece of carbon got between the valve and the valve seat...the valve got too hot...and then BAM, no more exhaust valve.

So while I had it apart I cleaned the throttle body and intake using...oven cleaner. This may have been a terrible idea in hindsight. Maybe the cleaner cooked one of the sensors? Or maybe I'm crazy and somehow the timing really is off?

EDIT:

Just to show everyone I haven't lost my marbles...

Lost Again

I'd start with re-checking the mechanical timing - timing belt marks on the cam and crank....could you be a tooth or two off?

Are you sure all of the air is out of the cooling system?

Are there any stored codes?

No telling what the "oven cleaner" might have done.....don't start replacing anything until you answer and verify the above.

GhostAccord

Sounds like it could be a vacuum leak.

oven cleaner will continue to eat away at aluminum if it was not rinsed off properly. Never sprayed any of the sensors with it, but it very well could have melted a hole in part of the intake air rotary valve (IAC/FIT) This could cause an erratic idle.

As far as the timing goes, did you have the ECU set to base timing when you checked it?

As long as the mechanical timing is on. These engines do not have any other sort of external ignition adjustment. All adjustments are made by the ECU based on signals received from the PGMFI sensors. If it is off then there could be a sensor that is not reading properly. They don't always have to throw a code. if they are still sending a signal that is within the range, it may not throw a code right away. However it would adversely effect the engines performance.

jmille25

Just to give some closure...I ended up replacing the IAC valve and everything is running great!

I decided to replace the valve after unplugging it when the car was running and there was no corresponding drop in the RPM's. So if anyone feels like doing an awesome job cleaning their intake...take the sensors out first!

GhostAccord

Glad to hear you got it working.

Note about removing sensors, no need to remove them all. Just don't use oven cleaner! There are a number or good sensor safe solvents out there.