Possible Detonation -.-

[boznuttz]

It really feels like Murphy's Law applies to me this year, lol.

I replaced my TPS a few weeks ago since it was pretty bad and my timing kept advancing under regular driving conditions. My car is usually kept at the college I go to, and I was going to drive it back home to replace the TPS and a few other items. The car is currently N/A, but since the semester is over, I am ready to boost again.

On the way back to my house, I heard quite a bit of misfire and the car would literally feel like it was jolting in gear as it misfired here and there. I knew the car was advanced and it really felt crappy as I drove it back home. While coasting in first and second gear, it felt as if I was tapping the brakes every few seconds because the car jarred back and forth as the engine misfired. I knew it wasn't going to be good, but I was stuck in heavy traffic and the next exit on the highway I was on was a good 20 miles away (I hate upstate NY highways).

When I replaced everything and busted out the timing light to set it back to stock, I saw that my timing was advanced beyond 30 degrees. I reset it back to 20, but I'm really nervous that the damage might have already been done.

When I first started driving around back at base timing, the car felt fine and accelerated smoothly up to about 4 or 5k rpms, after 4 or 5k rpms, it just felt like the engine wouldn't pull hard any further.

I tried starting the car earlier today. The battery is dead, and the car has been laying under snow for quite a while now. I tried jumping the car off of my friend's jeep, but it sounded like it would barely fire. It would crank and fire for a split second before dying out. I have a spare battery on the way, and I have high hopes of just replacing the battery to be able to drive home.

What are the symptoms to check for engine damage after detonation? I know that when I get back, I'll check the compression and spark plugs first. Would cracked ring lands cause decreased compression? What should I look out for?

I tend to worry a little too much and assume the worst quite often, so I'm hoping this is just a minor issue. I would liek to figure it out before I go ahead with any plans to boost again.

Could cracked or damaged ringlands affect the drivability of a car or the ability for a car to start?

I only want to replace the pistons and rods if I absolutely HAVE to, since I have a lot on my plate over this winter break.

Could I have detonated that much driving a N/A KA with timing that advanced...or could it have just been a rough ride with a lot of misfiring?

Edit*The car itself has a broken stock exhaust and is pretty damn loud. I haven't heard any metallic sounds, just al ot of misfiring.....then again, it might be too loud and could have drowned out any knocking or detonation.
Modified by boznuttz at 11:48 PM 12/19/2007

[boznuttz]

My brother's SR would stutter and misfire like hell as well with similar symptoms, but the only issue we really had was that the battery was about dead as well. We replaced that and it ran like a champ.

How would I be able to tell if I had done any damage to my engine without pulling the motor?

[bruinbear714]

What's your spark plug gap at?

[boznuttz]

Stock engine, everything was back at stock. I'll pull the plugs soon enough and check how they look. I might be working myself up a tad, because the car accelerated fine, the misfiring only occured when I was barely on the throttle and coasting.

No metal on metal sounding pinging, and at no time at all did I hear any sounds like bb's in a can.

All I heard was a few pops and stutters here and there as I let off the throttle.

[scheffler]

Listen to your motor. Get a stethascope and a like a 1/4" (dosen't have to be exactly 1/4") metal or even a fibergalass rod would work just something solid. Put one end of the rod on your motor and the other end to the listening part of the scope. Move it around to all cylinders and just listen to your motor.

[spooled240]

if you blew your engine then it would probably be blowing blue smoke and compression would be lower..personally I think your car is fine if it drove and accelerated ok. Think about it, accelerating is when the piston is under the most stress (load, low rpms, good amount of throttle) and if it drove ok then i think it's fine imo.

[C-Kwik]

A compression or leakdown test would be the best way to check. Cracked ringlands and/or damaged cylinder walls will both yield low results. Damaged pistons tend to become noisy though. So if it sounds smooth, you may be okay there. Damaged walls may sound normal. If you can get the engine running simply pull the crankcase breather hose to feel if there is a gush of air from excess blow-by. Perhaps wait until the engine is warmed up though to make sure the oil is providing as good a seal between the cylinders and the pistons as possible.

[Florida240sx]

Due a compression test and if it ain't blowing smoke then your probably just fine and dandy

[boznuttz]

I'm almost positive that my timing chain slipped for one part. And I'm thinking that my TPS is probably shot since every time I tried to reset my timing for the car to run right, it would reset itself back to what it was before.

I'll find out for sure about all this in the next few days.

X-Mas time is one hell of a busy time, lol.