Liquidnutz

I had the oil changed in my Z last week and about thirty minutes later it started missing badly. I had the codes read and it gave misfires on multiple cylinders (cam) and it gave a code for the front knock sensor. Well I put new plugs in it and it did not help so I pulled it down to see if I could see anything wrong ie broke valve spring or bent pushrod. When it started doing this I was just easing around town so it wasnt reving high or anything like that. I found no broken valve springs or bent pushrods but the front knock sensor was not plugged in. I plugged the knock sensor in and put everything back together, now I still have the miss and it backfires while idling. Has it possibly jumped time or something like that? I hate to take this thing to the dealer and let them look at it because I know that it will cost a fortune but I am running out of ideas here. If you could offer some advice I would appreciate it

Nine Ball

iTrader: (38)

Try resetting the PCM. Disconnect the batter, or pull the "PCM bat" fuse with the key in the on position. Turn key off and put the fuse back in.

You might also check for air leaks behind the MAF. Plug wires could be faulty as well.

-Tony

Liquidnutz

Thanks for the tip Tony I will check those things out again. I'm gonna tear it down again and go a little deeper to see if the problems lie deeper.
Knight

Pro Stock John

iTrader: (34)

Yeah, make sure everything is plugged in.

Basically check everything.

Why was the knock sensor unplugged.

Pro Stock John

iTrader: (34)

I'm hardpressed to imagine what happened as a result of the oil change.

Mike, I'd be checking a lot of things before I took it to a dealer.

With the car cold and with good light behind you I'd...

-check all plug wires
-check all electrical connections for MAF, IAT sensor
-check all PCV lines and air hoses
-i'd reset the pcm and see if the car runs better.

PCM might have richened things up to try to save the motor but that would only be due to something going on.

Liquidnutz

Thanks PSJ I plan on tearing into it again starting this evening, so hopefully I will come up with something. I dont plan on stopping this weekend until I figure something out. Maybe it will end up being something simple. Thanks for the input fellas if yall have any more ideas just keep them coming and I will keep trying to figure this thing out.

Thanks Mike

WMSuperSport

iTrader: (23)

Make sure the individual intake gaskets are in place properly.

Did you do any previous engine work earlier that couldve resulted in this?

Liquidnutz

Havent figured it out why it was unplugged yet, just know that after I got the intake and all off of it I held the little wire and pulled the plug up out of the hole and sure nuff out came the wire so I plugged it back in and made sure that it clicked. Tugged on it and it didnt come loose so I figure it wasnt hooked up. Put everything back together and it still doesnt run right. Going to tear it all back down this weekend and see if I can find something else.

Thanks MIKE

Liquidnutz

Well gentlemen it looks as if I will be investing in a new shortblock for my little Z. I still have no idea what the crap brought this on since I havent run nitrous or anything on this one but I do know that all cylinders except number 7 had around 220 pounds of compression and number 7 only had 120. The problem has gotten worse over the past couple of days and now I guess that I will start preparing to pull the friggin engine. If you guys know where I can get a good shortblock then give me a heads up. You can email me at fbodyfan@yahoo.com

Thanks Mike <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Pro Stock John

iTrader: (34)

That's bizarre.

Maybe you should go to a shop and get a second opinion, maybe you got a false reading on the compression test.

Did you do a big over rev and bend a valve?

JWRENCH

I'm not sure on LS1's, but one time I heard of the ring gaps lining up on a piston and doing that for a few days then went back to normal.

Red2000SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by mike2002:
<strong>I had the oil changed in my Z last week and about thirty minutes later it started missing badly... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry if this is a dumb question, but have you checked your OIL? I didn't see you mentioning that was something you checked.

That is the first thing that popped into my head before I even got past the first sentence of your post. I had a neighbor ruin an engine after getting his oil changed at one of those quick change places - morons didn't tighten the drain plug back up and oil slowly leaked out.

Liquidnutz

Well fellas I checked the oil and it was good, ran compression test again and acheived the same results. I guess that I will start pulling the engine this upcoming weekend. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Nitrousguy

If I could I would like to give you a little help with pulling the engine. I just did mine a few weeks ago. And let me tell you it's a tight fit! I have a six speed manual trans and there are three bolts on the top and drivers side of the bell housing that are very hard to reach. All bolts 15mm. Next, if you can remove the crank pulley those few inches can really help when trying to clear the radiator support. If your intake in not off, here's a little trick. Remove engine mount bolts and then remove the mount from the engine block. It helps keep the engine low. As you know there is not a lot of clearance under the windshield. At this point when you try to separate the engine from the trany, use the pry bar slots on the side of the bell housing. They really help. They are hard to see but once the exhaust in unbolted, it should be easier to find them. The guide pins are right next to them. They were very tight on mine.

I removed my engine with only removing the AC compressor, PS pump and the Alt.

Good Luck!

Liquidnutz

Nitrousguy: you have me a bit confused here, did you pull yours out of the top? I was under the influence that ls1's came out the bottom. I know thats the way they did my 2002, of course the dealer did that one under warranty and this one is coming out via the *** pocket warranty.

PewterZ

Damm this is bad news......

Liquidnutz

Heres an update for all of you interested in this thread, what leaves a nice sticky film on the inside of your intake and intake ports, makes your valves seize, and eats up your cylinders along with your rings.

Any guesses?

Well let me help you out: ******* SUGAR!!!!!!!!

Now all I gotta do is find the son of a bitch that got my ***.
<img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />

TanRchy

omg.. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> dude that sucks. Good luck to you...

niphilli

Mike- First off I am sorry this happened.

Second off-Call your insurance company. If the car is fully covered it should have some sort of provision for Vandalism.

-Nick

gwj

Are you saying that sugar got past the fuel filter? Or did someone dump it down the intake?