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Accidental overrev and now problems

Z

zakatak

New CEG'er
Joined
Nov 27, 2001
Messages
5
Location
Bozeman Montana
Hey guys. So on my way home on the highway earlier today, I had a near miss with a couple deer at 75 mph. For those of you who are not from Montana (all of you?) this really isn't that uncommon, but in my scared/relieved state, I shifted back into gear to get back up to speed and somehow hit 2nd instead of 4th. Stupid, I know, but I was preoccupied with what had just happened. The engine revved to the moon before I could get the clutch back in, but sounded fine during and after the overrev. I pulled over to see the damage and, at idle, the engine missed and shook a little. It has the same misfire under any acceleration, but is not noticeable at highway speed (I was in the middle of nowhere with no cell service, so I had to drive it home). No problems though, it seemed to run ok and sounded ok, but still missfires and has kind of a pulsating power. I can take it to a mechanic if need be, but seeing as I'm a broke college student, that is a last resort. Any ideas what may have happened and what I need to check before I drive it again? Thanks in advance for any help you can give me.
 
Something came loose. Check to see if all clamps , hoses and wiring is in its proper place.
 
Has anyone ever heard of the two halves of a DMD slipping in relation to each other? I wonder if revving that high that quickly may have caused the rubber damping part of the damper to slip on the pulley part of it since they're just glued/pressed together? I found an old post in the old forums that describes the same thing that happened to me, but it was never updated with the final solution to the problem. It really almost feels like the engine is out of balance and seems to get a little better the faster it is revved. Nothing under the hood is loose or anything like that.
 
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No ideas anyone? I am supposed to be driving the car home (~200 miles) for thanksgiving on Wednesday morning and I'm not sure if it's safe to do so.........
 
I would drive gently home, as long as there is no banging or knocking from the engine and it does not stall. Or rent an appliance (Chevy Malibu Classic?) to drive if possible.
 
So, not much help here so far, but I got the car home and replaced the DMD with the old crank pulley just to check it off my list. That turned out to be a whole lot of work for nothing. The problem is the same as it always was. I pulled the plugs and ran a compression test while they were out. The plugs looked fine but the compression was a little scary. Most were right around 145 psi, but one was 160 and one was 115. Not good I know...... Since the car seems to misfire AND be out of balance, I wonder if I might have hit a valve on the low cylinder and stretched a rod on the high cylinder? Either way, it looks like I'm biking it until college is over......... Anymore ideas?
 
Maybe Big Jim or Tony 2005 has ideas? You don't have a dead cylinder, but it would run a little rough. I have found it is tricky to get the tester to seal sometimes. Have you checked ignition wires/or for carbon tracks on the plug insulators. or for fault codes?
 
zakatak said:
So, not much help here so far, but I got the car home and replaced the DMD with the old crank pulley just to check it off my list. That turned out to be a whole lot of work for nothing. The problem is the same as it always was. I pulled the plugs and ran a compression test while they were out. The plugs looked fine but the compression was a little scary. Most were right around 145 psi, but one was 160 and one was 115. Not good I know...... Since the car seems to misfire AND be out of balance, I wonder if I might have hit a valve on the low cylinder and stretched a rod on the high cylinder? Either way, it looks like I'm biking it until college is over......... Anymore ideas?
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No ideas but the numbers, as you suspected do not look good. Per Big Jim, rule of thumb, lowest and highest should be within 25% difference. Of course, make sure you did the compression test correctly.
http://www.contour.org/ubbthreads/s...er=1057498&page=&view=&sb=5&o=&fpart=all&vc=1
 
The rule of thumb is lowest cylinder less than 25% lower than highest cylinder. You are right there. 75% of 160 is 120.

Try adding about a tablespoon of oil through the sparkplug hole and reading the compression again. If the oil brings the compression up to about normal, you usually have a ring/cylinder wall/piston problem (rings not sealing). If there is no or a very slight increase, it is most likely valve problem. My guess is that you floated the valves and one kissed the top of a piston, binding the valve very slightly.

If that is what it is, there is no shortcut. You need to pull the heads.
 
Damn...... I wanted to hear something good:) I'm pretty sure I did the compression test correctly. I used a nice snap on tester and cranked 8 times on each hole. I appreciate all your guys help, but I think we've probably figured out the problem...... It's kinda sad, I've had the car for 5 years and put a lot of hard miles on it (racing around like an idiot back in high school) and I finally hurt it with a stupid mistake on the highway. Oh well, I guess I get to tear into my first duratec now. Also, just FYI, if the car truly was in second and the clutch wasn't slipping at all, the engine was spinning at around 9400 rpm if my math is correct. Impressive that I've been able to put 400 miles on it since then :)
 
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