Subject	Burnt Exhaust Valve
Posted by	inf on August 14, 2012 at 12:43 AM
	This message has been viewed 413 times.
Message	I'm not sure if this theory sounds legit or not but... One of my Z's has been having trouble passing smog, high nox (1300ppm). I've done absolutely everything under the sun to reduce them including new cats, o2s, checking timing, checking for vacuum leaks, new plugs, new oil, completely cleaning the EGR system and completely checking for operation. I swore I checked the injectors before and they were all within spec, but this time around I found the complete driver side bank to be all out of range. Ranging from 16ohms to 30ish. The Z has been having a puttering noise from the exhaust and a zinging noise pipes. It wasn't likes this when I bought it like 6 months and less than 300 miles ago. Anyhow, I figured it was a misfire. I ended up replacing the injectors and now the puttering/zinging noise is even worse, the idle is jumping around and the engine is shaking a little. I've concluded the number six cylinder is misfiring after doing a power balance test. The cylinder has a new injector, injector connector and spark plug. I used an inline spark tester and it checks out ok. The injector is clicking as well. My theory is that the three injectors ran lean and burnt the exhaust valve(s) (primarily in the number six cylinder / I have yet to do a good compression test since the tester didn't hold peak psi, but it went back down to 0 immediately) which is why there is an even greater and more pronounced misfiring putter after replacing the injectors with in spec ones. Does this sound possible? What gets me is that my other Z which had some dying injectors before has always had them simply die and I knew right away...this Z I'm dealing with now had all of the injectors still operating, but out of spec...and then burnt the valves...I'm mean how is one supposed to know their valves will burn then? The vehicle by no means was maintained as far as I know. There's 180k on the odometer and the engine bay had tons of sand in it for some reason. Perhaps the possible lean condition contributed with the bad maintenance lead to these valves being burnt.
Follow Ups	Burnt Exhaust Valve - inf 00:43:34 08/14/12 Its possible that you pinched the oring when you - michaell32 06:15:06 08/14/12 you're jumping to conclusions - aliaZ 06:53:49 08/14/12 He still has out of spec injectors (n/m) - ZUL8TR 08:38:03 08/14/12 he said he changed them (n/m) - aliaZ 12:54:08 08/14/12 Right, I was confused by his statement about out of >>> - ZUL8TR 07:04:29 08/15/12 Ok, I got a working gauge... - inf 12:46:33 08/14/12 Well apparently that 180 psi isn't an error.. - inf 12:56:04 08/14/12 remove the spark plug on number 6 - aliaZ 13:00:23 08/14/12 I inspected the o-ring and it looked bigger than others - inf 13:59:21 08/14/12 hmm...my last post didn't post... - inf 16:13:21 08/14/12 does it click when you apply voltage to the injector? - aliaZ 16:21:53 08/14/12 it clearly clicks in pattern using the screw driver method. - inf 17:48:54 08/14/12
Post a Followup	You cannot reply to this message because you are not logged in.