HELP!!!! Car is missing now!

[Bad99GT]

Well, long story short, I went to the track Sat. night for some runs with the new tune. I made two passes. First pass was not so great, but still my best, 12.21@111 with the car feeling sluggish in 4th gear. I made another run less than 10 mins later and something went way wrong. When I got into 4th gear, the car was detonating horribly. I was on the brakes immediately but not soon enough. I coast through with a 12.30@108 on the brakes at 1000'.

OK. I pulled all the plugs out to check for oil to see if I broke something internal. No oil on plugs, but one had an electrode burned off. Replaced all the plugs and started and it still feels/sounds like it is missing on one cylinder. I think I may have broken a valve spring, but I'm not sure. Anyone have any ideas or similar experiences? I just had this car tuned less than a month ago and now this shit happens. Any help is appreciated.

Daniel

:mad:

[HyperGT]

Dude that sucks. Its so close to BG and now you pull this?? Arg!

Just kidding, anyways man that really bites. Sorry I can't help you much. I'm not too edumacated when it comes to internals. Just yet at least. I know after racing with the blower I'll eventually get very friendly with my engine internals.

Keep us posted and I hope it is something minor.

[Brandon Alsept]

Besides the detonation was there a noticable change in exhaust tone such as a dead sound? That is almost the same exact story from when my car went. How high where you reving it ? and what valvetrain are you running?

[HyperGT]

When you say your motor "went" what went wrong with it? I know it was something that crippled it, but what exactly happened to it?

[Bad99GT]

Brandon-- Yes, the exhaust note changed big time. I wasn't revving it high, 6200 at most. It has a stock valvetrain in it still. When it idles now, it sounds like a 5.0 with an F303 cam in it. This sucks!

Daniel

[ChickInHer01GT]

Originally posted by Bad99GT
. First pass was not so great, but still my best, 121.21@111
:mad:

I'll say, that ET is a little slow for that mph. I saw a 90something dodgeshadow with hot pink rims click off a 34 once but damn.:lol:

[Bad99GT]

Thanks Brooke. I edited the post. 12.21@111

[Bill Putnam]

You need to do a compression test my guess if you either FUBARed a piston or valve/valve spring...

Bill

[Bad99GT]

You are exactly right Bill. Compression test will tell the tale. Thanks for the advice.

[984.6gt]

My car did that when I sprayed it to hard, it idled like a CRAZY 5.0, just like you said, I kinda liked the sound, but not the outcome, the whole motor was fucked, it was cheaper for me to replace than repair. Does it shake like crazy? Does the exhaust sound "Airy"? If so I think you have a similar situation as me. I am not sure of the exact problem my motor had, all I know ias that it was 1600 to fix, and this was with my worker discount!! Good luck, , I hope you don't have any major problems, but if so, you will be VERY suprised how cheap you can find a low milage 4.6L 2V. My car was acting funny lately and I just replaced the fuel pump and all was well, good luck.

[white99gt]

Based on what i know about modulars.

You killed a valve.

The stock valves cant take much det ,just like our pistons.To much and they will burn easy.

Had a friend burn a stock valve with a forged bottomend while tuning his d1 setup.It had a pea size hole burned in it.(was being tuned by jms)

Hope for the best.Maybe you just hurt a spring.

This sucks this close to BG.

:barf:

[Brandon Alsept]

Do a compression test and I am guessing you will come up with your problem right there.

I have yet to determine what exactley went wrong with my motor. I know I had a valve guide come apart, and that I had some major piston to valve contact. I am gonna have the springs tested and see if they maybe went bad or what happened.

[ChickInHer01GT]

Yes.... compression test :agree:

/acting like i know what i am talking about.

so useless:mad:

[Bad99GT]

you will be VERY suprised how cheap you can find a low milage 4.6L 2V

My 2v is forged on the bottom end so a stock replacement is not an option. I am hoping it is a valve/spring and not a pistion. There wasn't any oil on the plugs so that is a good sign. Last time when I broke some pistons the plugs were covered with oil. I'll figure it out with a compression check. Bill, you're right about this sucking this close to BG. DAMMITT TO HELL!!!!:mad: