I drive a 2003 Cavalier. Last year I added nitrous to it and have haad no problems at all. However, during the winter, i have encountered a problem. I take my nitrous out during winter and do not use it at all.

One day I was driving normally and got up past 3000 rpm when I had a sudden lag in power and a sound like one of my cylinders was not firing properly.

My check engine light lit up and and I released the gas and cruised to a stop. My car kept running, however, but it acted as if, like it sounded like, one of my cylinders were not firing.

I drove it home and checked all my plugs. The plug closest to the driver's side wheel was pushed in a bit with some indication on the very tip that it ahd been hit. I guessed at the time that the cylinder must have hit the tip of the plug, causing the gap to become virtually non existant.

I regapped the plug and had no other problems until a week later. I had gotten up past 3000 rpm in the meantime and experienced no probs. However, this time it happened again but this time the car actually died and stopped running, causing me to pull over immediately. After trying to start up quickly and failing, I let it sit for a minute and then was able to restart it. Once again, the same problem had occurred as I rechecked the plug. I went and bought a new plug, this one much shorter than the other one. I put it in and everything ran fine until a few days later when the problem occured again. Only this time I had lots of people in my car with suitcases in the trunk, and was not over 3000 rpm when it happaned. Once again I checked and the plug tip had been dented in obviously.

I am not exactly sure how my piston could be hitting my spark plug on that side only. Perhaps whatever the bottom of the piston is attached to is loose somehow (I assume from running nitrous). Is there an easy way to open up the block and fix this?

Has anyone else had this problem? The new spark plug has already gotten a bad carbon buildup also after being in for about a week. My check engine light is off now but I assume my o2 sensor may be bad. However, if I don't go above 3000 rpm I have no problem. I would imagine the problem will only get worse, though.
Any suggestions?

Does your car make any sounds when its running? does it run like crap?

Sounds like something is broken and keeps hitting the plug, and staying in the cylinder... ring lands?

Yeah, you need to rip that head off very soon. Sounds like the ring land has lost a chunk and it is floating around in there, most likely causing lots of damage to the head. Hopefully you havent screwed up the cylinder yet.

Or cylinder liner is broken and causing pieces of the piston to come apart.

you bust some piston tops. I did the exact same thing with my LD9, it happened 3 times before I actually stopped driving. I just had some extra plugs and kept going. When it happened to me I didn't have money (in school) to fix it, so I just kept on going. But that is not recommened, even if you can look into the cylinder you will likely see some damage to the piston (cylinder at BDC bottom dead center) then look with a flashlight.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Matt Linke says,

Does your car make any sounds when its running? does it run like crap?

Sounds like something is broken and keeps hitting the plug, and staying in the cylinder... ring lands?

***When it runs it sounds fine. No check engine light or anything. Runs fine no power loss. But on occasion when over 3000 rpm something will cause the plug to be hit and the gap becomes smaller. I can see small tap marks on the tip of the plug so something is hittin it. The tap marks are very small circles, so maybe it is the very top point of the piston?

Rollinredcavi says,

Yeah, you need to rip that head off very soon. Sounds like the ring land has lost a chunk and it is floating around in there, most likely causing lots of damage to the head. Hopefully you havent screwed up the cylinder yet.

I apologize but I am not sure where the ring land is located... like I said above the very tip of my plug has small indentations centered on one area. i would think if something was floating around it would do damage to other parts of it and also make the car run badly constantly....this is not happening. Normally I run the car slow and easy and get no problems at all...

I went to Autozone today and showed them and they confirmed that it could indeed be that the very top point of my piston may be hitting the plug ever so slightly. Is this what you mean ge_forcez22?

It is very strange as I would think the car would react at all times, whether or not I am idling or taking off and getting to 3000 rpm.

I posted a video under the boost section called "280whp @ 11 psi LD9" watch that video, I think the 6th picture is what you will find when you pull the head off.


EDIT: I found the link

http://media.putfile.com/Cavalier-Neon-Datsun-Cobalt-dyno-video


you can see the pistons are broken away at the sides, those pieces bouncing around wreck plugs... but the rings still seal when they go out the exhaust.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

What were you using for fuel control and were you running a wideband?



99.999999999% is you overheated a piston and part of the ring land cracked off, thats what hit the plug. Running the engine after finding a dented plug was a very BAD idea. Once you see a dented plug you already know that something is either A) in the engine that isn't supposed to be there or B) something inside the motor has broken and is now floating around inside it. In the future, don't attempt to drive the car in that condition, either pull the head to inspect it yourself or have a qualified mechanic do it. By running it as long as you have chances are very good now that whatever piece is in there and floating around has scored the cylinder walls and now you're going to need to either a complete rebuild or to replace the engine. A buddy of mine cracked his ring land also but just got lucky and it did no other damage then the piston and spark plug. All he did was replace the pistons, rods, and rings with forged units and then put it back together. Been running fine now on 18 psi of boost for several thousand miles but I really doubt you'll be that lucky.

What should you do? The head needs to be pulled at this point and a thorough inspection conducted. End of story. No way around it. Something is inside the combustion chamber that shouldn't be there and it needs to be dealt with before any more damage is done.




Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said

time to replace the motor , pistons are broken

ive had it happen twice with a 2.4 , first 1 puked oil every where , 2nd ran like a top tell another piece broke off , never smoked

Yup... as the GTP guys call it, you "chipped a piston". I did the same thing on my s/c'ed 2.4L last July. Busted off a piece of the ring land, but the compression was mint... so I figured, I just blew the piece out the tailpipe and the ring kept it going... then the ring gave out too... that was messy

Now I'm (still) doing an engine swap...

Ok I am not sure something is floating around. I plan on opening up the head soon. I do not drive it now as I have another car;

But if something was floating around, wouldnt there be problems all the time??? This is my main question. When all the plugs are gapped fine, my car is perfect. I sometimes put it above 3000 rpm and it runs fine. No unecessary noise, no check engine light, no loss of power. Even when i go above 3000 rpm at times nothing happens. On occassion, in testing it, above 3000 rpm it will something floating or the piston itself will hit the plug tip just barely enough to offset the gap slightly. When I put in a new plug it works fine and then in testing once in a while I get above 3000 rpm range and then it happens...smaller gap than normal, with very small minute dent in the tip of the firing tip of the plug. It really sounds like the connection between the rod and piston is loose and during higher rpms the piston rises higher than normal. This weekend i hope to open up the head and see what the heck is going on.

thanks for all the suggestions.

If you're running a stock-length plug... or shorter... and something is closing the gap while running.... then something is definitely wrong. The most likely culprit is a chipped piston, as you've been running nitrous and it looks like you're not using anything like an MSD DIS-2 to retard the ignition timing. (BTW, that's a guaranteed way to kill a motor... just nitrous without the supporting mods = boom!)

There is no way an otherwise stock motor could push the piston up far enough to close the gap on the plug.... unless you're running a significantly longer than stock plug (I don't even think those exist for the Eco... so...) The fact that it happened to you twice, even using a shorter reach plug... means there's something in the cylinder moving around, just enough to close the plug up.

I did it to mine.. and ran for 3 months until that ring gave out too... at that point, the engine was toast.

If you're running a stock-length plug... or shorter... and something is closing the gap while running.... then something is definitely wrong. The most likely culprit is a chipped piston, as you've been running nitrous and it looks like you're not using anything like an MSD DIS-2 to retard the ignition timing. (BTW, that's a guaranteed way to kill a motor... just nitrous without the supporting mods = boom!)

There is no way an otherwise stock motor could push the piston up far enough to close the gap on the plug.... unless you're running a significantly longer than stock plug (I don't even think those exist for the Eco... so...) The fact that it happened to you twice, even using a shorter reach plug... means there's something in the cylinder moving around, just enough to close the plug up.

I did it to mine.. and ran for 3 months until that ring gave out too... at that point, the engine was toast.

i was indeed running a shorter length plug the first time the problem occured. But I switched new plugs which ended up being longer and than the problem only occured that once. Total l have had this problem on 6 occasions in testing.

I do have a question for you Lenko: Did you notice a loss of power during the time you had this problem? If so was this loss all the time at all rpms? Could you hear something floating around inside the cylinder at all? Wow you ran for 3 months with a chipped piston? How did you know you had a problem? Was the engine running rough the entire time, no matter which rpms you were at? As an aside, was your engine toast because the piston gave out completely?

If there was something floating around though, wouldn't it always hit the plug eventually? My recent testing has been just driving the car for about one hour a day and not going over 3500rpm, and have done this for two weeks about and have not had any problems with the plug...so you think there still may be something floating around?

Did you switch up your engine components or just decide to rebuild your engine?

My problems started in May 06, when I redlined it in 3rd gear to pass a semi on the freeway before the two lanes merged into one... I'd downshifted from 5th to 3rd to "gun it" and redlined it... when I shifted back up, it sounded like a lawnmower... stuttering on giving it gas, and it has a serious lack of power. I knew I'd busted something but I didn't know what. I pulled over at the next town (about 5 km's later) and shut the car off... listened to the engine, it sounded like one of the cylinders wasn't firing... it was running on 3 tho... I didn't have any tools with me, so I limped it home another 400 km's, but I couldn't get much power beyond 3500rpm, and going up and down hills I was lucky to get more than 90 km/h speeds.... fuel economy was absolute crap too!

I got home, pulled the plugs, noticed #4 had closed the gap. No actual damage to the plug, just the gap was closed up so the ground strap was touching the electrode... so it wasn't firing. Soaked in fuel too... I did a compression test, had 210 on all four cylinders... I opened up the gap and re-installed the plug (after cleaning it) and the engine ran fine... no problems at all!!

I ran it for another three months without any problems until one day in July... I was gunning it while turning a corner (I had to beat traffic...) close to redline in 1st gear, maybe 30-35 km/h and it went again.... sounded like a lawnmower, no power upon acceleration... luckily I was a few blocks from my work so I parked it there, then called my girlfriend to bring me some tools... once it was cool, I pulled the plugs and lo and behold #4 was smashed flat... not just closed, but there was definitely mechanical damage - something had hit the ground strap and smashed it closed. Not good... there's no way the piston can come up far enough to hit the plug (it would destroy itself on the top of the head first, then the valves, before it ever got far enough to touch the electrode)... unless there was a piece loose in there.... or something else had fallen into the cylinder and was mashing around in there. Compression test revealed all I needed to know - 210, 210, 210, 105. I'd killed it... and good.

So.. I towed it home and pulled the engine apart.... turns out a piece of piston #4 ring land (the top edge before the first compression ring) had broken off, and somehow fit between the valves to fly out... there was nothing in the engine except the damage that the piece left.

I figured that I blew the piston chip first back in May... then the ring held up til July (ok, that's two months...) until it gave way as well.



So... my suggestion is.... do a compression test... if all are equal, you've probably chipped the piston but your rings are still intact. If you're down on one (or more) then you've lost the ring too.

If you keep smashing plugs... and you're running the proper reach plug... then there's something in there. Either a piece of piston, or valve, or something foreign got in. I've seen someone on here that found a screw smashed into the head... how it got in there, someone knows but isn't saying!

Anyway.. you will end up replacing the piston at least... if you run it and do more damage, you might need a new head, multiple pistons, even a new block. I'd open it up now and find out before you do the whole works in.

PS. Never run nitrous without something to retard the ignition timing!

If you broke something other than just chipping a piston you would know. if there was a problem with rod bearings, or the rods or a "loose" joint anywhere in the motor, you'ld hear the rod knock undoubtedly, highly unlikely that it occurs (with that problem) at only over 3000 rpm.

And I dont own a DOHC motor, but isnt the head concave towards the valves, leaving the spark plug at the highest point? IF thats true then the valves would be smashed first, and yould know (if it was a bearing or rod type problem).


Pull the head off the check things out... Best of luck on the fix, however think of it as a really good reason to get something better

Oh, and i forgot to include this in my first post: some versions of the ecotec ecu do not enter "power enrichment" mode until upwards of 5500 rpm... if you don't have a wideband installed, you have no way of knowing whether yours does this or not.... Its been shown that the stock ecu will lean your motor out to 14.7:1 air/fuel ratio pretty much no matter what you do while it is not in power enrichment, which is probably why you blew the piston. I saw one dyno of a guy using the hahn portfueler on top of his stock injectors, and the ECU STILL pulled out enough injector pulsewidth to keep the engine WAY too lean for boost. Chances are, this was your problem. Never EVER run a power adder of any kind, be it nitrous, turbo, or supercharger, without using a wideband oxygen sensor and gauge to ensure you have the proper air/fuel ratio. Retarding your timing is important also, but not nearly as important as maintaining the proper A/F ratio.




Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said

Wow you drove that far on 3 cylinders? You must have been cringing in pain the entire way home!

I see the logic in the piston not going up high enough, but it doesn't make sense for something to be floating around in there and only hitting the tip of the plug when redlining...perhaps I am not making sense...do you see what I mean?

So your ring flew out and was floating around during engine running?

I will taken into account running nitrous with ignition timing retardation...i had run it fine and was todl by many it wasnt needed, and had no probs for 2 years...but obviously it was needed or I perhaps wouldnt be having these probs now!

the land just knocks around for a bit, wrecks the head, bends a plugs then floats out the exhaust port. If you were to put a new plug in, you could easily sell the car and no one would ever notice, till it happened again. I can't believe this thread is still going on.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

I want pics when you figure out the problem