Hi Everyone! My 2006 3.9 Monte Carlo with 195,000 miles (I want it to go past 200K!) seems to have a strange problem. I was driving on the highway for about a half hour, everything was fine, no strange noises, no potholes, or anything unusual. When I exited, I coasted around the corner and went to accelerate, but the car wouldn't move. Tried again, no noise, it wouldn't move. I then noticed the brakes weren't working, and the steering wasn't working, the engine was completely off! I managed to just get into a parking lot without any power or brakes. I put it in park, took the key out and tried to start it, it made a terrible noise as it was turning over, but wouldn't start. There were no set codes, but a pending oxygen sensor code. I tried it a few times and let it sit for a while, same thing. I had it towed home, tried an old alternator, didn't change anything. I let it sit a while, and it somewhat started, VERY rough, for about 5-10 seconds before shutting off (did the same thing a few times). Tried again this morning, this time I noticed some heavy white smoke (still no error codes). Tried yet again, it clicked and wouldn't turn over at all. I poked around by the key, and it started VERY rough again.
Any ideas at all?
I filled it up about 30 miles before this happened, maybe bad gas? But it died the moment I came off the highway and slowed up, and the highway driving was absolutely fine.
Ignition switch, crank sensor, internal engine failure?
If the timing chain was off, or if a valve or lifter broke wouldn't that give some sort of error code (specifically misfire)? According to the computer, the engine isn't registering as misfiring, but whoa is it rough! Only other symptoms are when I turn the key off, it almost sounds like it sputters for a half a second, instead of instantly turning off, and I smell what I think is a fuel odor. The engine blew up once before (I spent a few months learning to rebuild it), and sounded and smelled similar, but I was getting misfire codes, right now I'm not. I also cleaned all the grounds, but maybe there is a break in one of them.
Any help trying to narrow it down would be great (it almost seems like it can be any of those, but it also seems like it can't be any of those). I'm getting a new ignition switch hopefully by Monday, but that was really just a guess.
Thanks in advance!

 

That's a strange one for sure.
Battery? Major Vacuum hose off someplace?
Here is a link to check for more possible solutions.
https://www.google.com/search?client...rlo+wont+start

 

Definitely strange. I think I've replaced pretty much every part in the car at one point, but this seems to be the trickiest diagnostic I've dealt with (everything has had some sort of specific hint, this one seems to have, well, quite a few possibilities, and quite a few possibilities why they aren't the problems). I mean, it seems like there has to be a misfire with the way it's running, but it says there isn't (I wasn't sure if it was possible for say the timing chain to have jumped, but not trigger a CEL). The battery did cross my mind, though it is reading 12.2V and is only 2 years old (though at this point, nothing would surprise me). I'll keep the thread updated as I go.

 

Could it be the MAF?

 

12.2V is too low to start it You should be at least 14 to 14.8 on a fully charged battery. I know what your thinking too, it's only a 12v system but back in the 80's I had an 85-86 Monte Carlo and my battery went bad after the alternator went bad and they showed me how it should be at 14 + I have confirmed this online as well. So?? something to think about. alot of stuff runs of the battery.

 

check the engine oil and the coolant level and condition of those fluids, see if that will start to clue you into where to look more in-depth. Also check the tranny fluid.

 

I switched out the ignition switch today (I thought with the way it broke down, this was a definite possibility). It started, but it was still VERY rough. I tried a few times. Not once was there even the slightest white smoke this time (yesterday you could barely see through it). I was trying to watch the Torque app to see if I could spot anything. The only thing glaring was the reported voltage on it was jumping all over the place..at times 13.9, all the way to 8, 10, and everywhere in between, and when I checked at the battery when it shut down, it was 12.2. I'm going to try to have the battery tested, and I'll also look up about testing the MAF. I had a pending p0300 this time, but only once, on the following startup it was gone. Maybe it will be as simple as the battery. The fluids seem to all be ok, so I think I can rule anything with them out right now.
So the updated status is it starts, but is not drivable and violently shakes. Time to try to rule out more possibilities. I may buy a fuel pressure tester, just to be sure it is getting fuel. I was worried it could have been bad fuel since it was filled very recently, but the highway driving was fine.

 

i'm guessing head gasket. Explains loss of power, white smoke, fluids in cylinders would give the rough engine conditions you see. My GF car suddenly lost power, and had white smoke after i put in new motor mounts 3 months before. When something goes and dies it can be catstrophic, not a slow death giving you notice.

 

I tried doing a compression test today. The first 5 were 140-150, HOWEVER, the last one is 0! Also, the cylinder with 0 has the spark plug covered in oil/gas, and the tip is actually bent in! The cylinder next to it also had oil/gas, but the tip was ok. I know I have to pull the engine apart, but any suggestions on what to look for? The last time something like this happened, the spark plug was not bent.

 

Bent spark plug and zero compression means something came apart and hit it - maybe a chunk of piston, maybe a chunk of valve?

Regardless, I wonder why bother pulling it apart at all? The engine is already at the end of its life in terms of mileage, so it's not like you're going to stick a new piston in and keep trucking.

IMO you just need to find a lower mileage junkyard engine (assuming the rest of the car isnt worn out too).