I know a valve stuck open and I guess bad rings but what specificaly would hold a valve open or make rings go bad. I only threw a multiple misfire code and I don't hear any ticking or anything, but the dealer says no compression.

 

Burnt valve,broken valve, valve not seating,hole in piston generally anthing that lets air escape combustion chamber. They need to do a leak down & see what the problem is.

 

Don't forget bent valve... Most common reason a valve won't seal, especially on these engines. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Please don't ask how I know this! <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" />

 

Hole in the piston! What happened? Give us some details!!!!

 

Well I was just driving normal and the car started to run real rough but no backfires and no noise. Then the ses light started flashing. I pulled over and hooked up the autotap and one code was there, p0300 multiple missfires. I drove it the rest of the way home about 2 miles and I let it sit overnight. The next morning I turned it on and it was still running bad but no codes. I even had all 8 misfire windows up and not a cingle one. I checked all the sensors,wires and couldn't find anything wrong. I did find a plug for the wideband tuning was halfway out but it still ran the same after I screwed it in all the way. So off to the dealer. On the way there the ses light was flashing again but still no backfires or funny noises, dealer looked at it all day and says I have no compression in one cylinder. Today they are going to tear it apart to see whats broken.

 

Sounds like a broken valve spring to me. It's not pulling the valve closed and allowing the air to escape into the intake or header.

 

Well I think I do have 941's

 

i had similar symptooms when my compression ring on #7 broke. Eventually the piston came apart and destroyed the motor, hence the new 389. The quick diagnosis would be to pop the valve cover, back off the rockers so the valves can seat, pull plug, pump cylinder with air. have your dipstick out, TB uncovered. then while pumping air put your ear (use a piece of vac hose as a stethescope) at each the dipstick tube, T-body then at rear exhaust tips. you will hear a steady stream of air very easily. When i did this, the air pressure actually blew the dip stick out of the tube! i had a BIG hole in the piston!!

 

Probably a broken spring.

Black Magic, I edited your sig... You are not a paid advertiser, cannot advertise unless you contact me.

 

Ditto the spring theory. Just pull the valve cover...

Shane

 

Cylinder number 3 valve spring is broke. If I give them a new spring the total cost will be $265. I guess i have a cool dealer.

 

How long can you drive around with a dead cylinder

 

You should really make a new thread...this one you dug up has been dead for about 9 years!

 

Holy Reborn Thread Batman!

 

lmao! Where do people keep getting this 9 year old threads from

 

Yeah because a bent valve seals better on a non LS based engine.

 

You must have taken the wrong friend's test. I ran into a similar one in wall works when I drove the car for a check. Even with the compression rings open, you will still get SOME compressions. In addition, your car would hardly move if it was only running on 3 cylinders.

 

Second time a TEN year old thread is exhumed! Doesn't ANYONE check post dates??

 

read back further -- it was exhumed ten years after in 2011!!!

It's been re-re-animated

 

Right. That's what I meant by the SECOND time a ten year old thread got dug up! LOL
Talk about recycling....