took the car to the track yesterday (road racing) it was very wet and cold here. yes we still run in the rain.
anyways, i got what felt like a missfire about half way thru the day. got worse as the day progressed. i can feel it all thru the RPM range and the idle is very week. i thought i had a loose wire, but no go. pulled the plugs last night and they are BLACK. way rich. put a set in that were out of a very low mile 02 f-body. fired it up and it runs the same.
o.k. - its not the plugs.
it feels like it is misfiring, but i get no codes and no misfires on any cylinders (a-tapped each cylinder). no knock retard.
O2's are moving around. TPS is o.k.
it has a really bad hesitation then you blip the gas. almost like a bog. oil looks good, no air in coolant.
i think i hear air leaking into the intake from one of the cylinders. all the springs look good. could i have bent a valve? cracked a piston? a dead injector would show as a misfire right? what about a stuck injector? i did pull one plug yesterday that was really wet w/ what looked like gas.
i wont get a chance to tear back into it till sunday. guess i'm gonna go ahead and probably pull the heads. i'll put in new injectors w/ the new heads i have comming.
any ideas?

 

make sure a cat didnt get plugged on you or a bad O2

 

i'm leaning towards the O2 thing also. i have no cats.
i just need to get out and drive it w/ a-tap going.

 

good luck glenn. let us know what you find out.

 

its not the O2's.
any help out there?

 

Just for refrence sake ho mnay miles are on the car and when was the last time the fuel filter was changed? as silly as that may seem the one on my 01 SS at 14,000 miles i changed it and after drying it out i couldnt blow through it but the new one you can blow throuhg like nothing and that car was a whole diff animal after i changed it. thats jsut a suggestion it worked well and madea night and day diff for me.

 

Do you have any kind of ram air setup?

Your MAF might be screwed. I mean, if it's not the O2s, no misfires (which eliminates ignition or fuel problems pretty much), gotta be the MAF? Maybe got damaged from water?

Dope

 

update -
its not the MAF, O2's, or fuel (have a pressure guage). plug #2 (pass front) is wet looking w/ fuel. also the intake runner for that cylinder gets MUCH hotter than all the others (as if the valve is bent, and bleeding compression back into the cylinder). you can also hear what i think is pressure popping back into the intake.
i have 79K on the car w/ a T1 and 941's w/ 30K. i was just 2 weeks away from a spring upgrade.
2 weeks ago i switched to 15w50 mobile 1. would this cause a lifter to pump up more than normal?

 

Maybe a broken valve spring or pushrod.

 

maybe try and compression test on each cylinder. Not sure but a bent valve could bleed compression. Might be what causes that intake runner to heat up...

 

Glen- where did it occur on the Track? Even though it may not have broken, the valvespring might have gone limp and will still hold the valve in place but is very weak- This is a common occurance for roadrace cars. This is another reason why we run triple springs on the TA car. BTW Ill call you tomorrow PM me your cell <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

 

You might have a bent vlv.comp.check on each cly.try that.

 

louis - PM'ed you on LS1.com.

 

Do a leak down check on the cylinders, this will show you a bent, or stuck valve in the form of leakage, compression check should show the same thing, no compression in the cylinder with the valve stuck or bent. I suspect it will be #2

Ed

 

thanks guys. i pretty much figured it would be that once i found no broken spring. i already have a set of GTP's S2's ready to put on, i was just waiting for some off season time from the track days i attend. guess i should have made time. sunday i'll have time to pull the rockers and see if air a is leaking past the valve and into the intake. if it does, then i'll pull the heads possibly before X-mas and see what the damage looks like. guess i should go ahead and do a compression check before i pull the heads to make sure i dont have any other problems.

<small>[ December 12, 2002, 09:23 AM: Message edited by: Glenn98ZM6 ]</small>

 

ok, i found the prblem.
its just a broken valve spring. i guess i was just tired when i pulled the covers, cause i missed it. hell it took me two looks tonight to see it.
it broke down on the bottom 1/4 of the spring, and had started winding in on itself. i pulled the intake rocker on that cylinder and pushed down on the spring w/ my hand and it went down about half way. it pulls the valve all the way up, so i dont think it hit the piston at all.
anyways, i know that sounds wierd, but thats the best think i could have found broken.