Author Topic: My car exploded  (Read 7568 times)

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #30 on: August 24, 2013, 10:13:05 PM »
Another friend said to me that the crank shaft sensor and cam shaft sensor are both known to go bad without throwing a code.   So may possibilities, I may just have the dealer diagnose.   At least we ruled a few parts out for them.

SunnyDaze

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Re: My car exploded
« Reply #31 on: August 24, 2013, 10:46:08 PM »
If you know anyone who has a Snap on MODIS or anything similar, you can view live data from sensors.

Typically, if a crank or cam sensor are bad, you won't have a minute of running fine then chaos. Most of the time the car won't run at all due to the fact that cam and crank sensors perform such a critical function.

Does it run fine until it warms up, or just for the first few seconds / minute? If it runs okay until it gets close to warm operating temperature, my guess would be that it's a sensor of sorts, but most likely not the cam or crank sensor.

When the car is not fully warmed up, the ECU runs in closed loop mode. Math people and programmers are not creative when naming things. Closed loop mode is exactly that; the ECU does not read non-critical sensors, instead it uses preassigned parameters to manage the engine. For example, instead of reading manifold pressure and exhaust gas composition, predetermined values are used in place of MAP sensor and oxygen sensor readings. Closed loop operation is very "baseline" - and very safe. It ensures an air fuel ratio that is rich to prevent damaging lean conditions.

Once the vehicle approaches warm operating temperature, the ECU switches into open loop mode, where it considers input from all sensors to manage the engine in such a way that it operates with maximum efficiency given the external conditions.

Most typically, when a crankshaft sensor goes bad, the ECU has no frame of reference regarding when to ignite the air / fuel mixture in the cylinders. The crankshaft sensor is not subject to open / closed loop operation. The ECU consistently reads crank position regardless of operating mode. The same applies to the camshaft sensor.

« Last Edit: August 24, 2013, 10:49:28 PM by SunnyDaze »

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #32 on: August 24, 2013, 11:13:09 PM »
All of this makes sense as I've always noticed that it takes about a minute for the idle to drop from about 1200 rpm to 800.   Today, it was when this drop was occurring that the engine would stall.

SunnyDaze

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Re: My car exploded
« Reply #33 on: August 24, 2013, 11:21:13 PM »
If you put it in neutral and give it fuel manually, does it still stall?

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #34 on: August 24, 2013, 11:26:24 PM »
Good question.   I was afraid of giving too much fuel and having another ginourmous backfire and manifold crack.

SunnyDaze

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Re: My car exploded
« Reply #35 on: August 24, 2013, 11:34:36 PM »
Well, we may be back to isolating what caused the fuel or timing issue that led to the backfire and the cracking of the manifold.

Without being able to get live data from your sensors via the OBD port, there's really not much else I can suggest without risking replicating the backfire condition. :)

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #36 on: August 25, 2013, 08:39:31 AM »
Yep.   That's why (unless resetting the computer as you suggested works), I think the next step is towed to the dealer.

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #37 on: August 29, 2013, 11:21:07 AM »
Okay, here is the latest.   

I did the three steps SD prescribed (clear computer, clean IACM and MAF) and started it up.   It seemed to run much better but I didn't road test it because I have to be to work in 45 minutes and didn't have time to have it shut off anywhere besides my driveway.

I observed one thing that may be a huge concern or may be nothing.   Right after I started it, I noticed that some of the "compartments" around the retaining bolts on the top of the manifold filled up with water.   Some filled, some were completely dry.   I never noticed this before but I also never looked for it.   Could this be a gasketing problem?   Is it a concern?

I'm tempted to buy a new middle manifold piece and the complete gasketing kit, but don't want to throw money after this vehicle if it may never be running again.

Opinions?   TIA.

SunnyDaze

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Re: My car exploded
« Reply #38 on: August 29, 2013, 01:49:35 PM »
There's no water in your engine, right? If something were leaking, it'd be antifreeze.

It's most likely just water that ran in through the cowl panel (where your wipers are located) and accumulated on the engine.

If I were you, I'd start the van and let it run in the driveway until it reaches warm operating temperature and when I'd check for any leaks.

If you feel that the intake has a leak, you can have it tested on a smoke machine.

Offline schwarcw

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Re: My car exploded
« Reply #39 on: August 29, 2013, 10:20:30 PM »
SD makes a good observation, plus it rained like hell the past several days.

It's good news that it's running.  Let's hope the worst is behind you!
Carl

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #40 on: August 30, 2013, 01:43:49 AM »
I will check it before I start it and after I run it a bit tomorrow.   Definitely not anti freeze.   I always smell that stuff, even with the smallest pinhole leak.   This was definitely clear water.

SunnyDaze

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Re: My car exploded
« Reply #41 on: August 30, 2013, 02:50:59 AM »
There is absolutely no way your engine is putting out pure water.

My guess is that your cowl trim is worn at very best. When it rains hard like it did, it probably allows some amount of water onto the engine.

Take pics next time!

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #42 on: August 30, 2013, 07:53:31 PM »
So I ran the car for about 20 minutes, got it well up to temperature.   It was running fine.   Gave it gas a few times, it dropped back down to idle smoothly.   No water appeared, I guess that had just run in from the rain.   I called a friend to see if he could pick me up in case it stopped while I was road testing it.   As I was talking to him, it shut off.   Am I still having a problem or could that happen to any car?   I will test again tomorrow.

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #43 on: August 31, 2013, 01:30:15 PM »
Okay, I sprayed the idle air control motor with WD40 instead of cleaner after realizing that they wanted this part to be lubed and tried again.   It idled great for probably ten minutes.   As soon as I put it under load, it shut off.

I'll have the dealer do diagnostics next week. :(

Offline Sir Thrift-a-Lot

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Re: My car exploded
« Reply #44 on: September 12, 2013, 12:10:24 AM »
Darndest thing.   I drove the car to the dealer.   It idled down too low once and I got battery light, but it didn't shut off.   I made it the rest of the way without issue.   The dealer let it idle for five hours and it never shut off.   So he called and asked my permission to drive it home.   He drove it to Delmont and back without issue.   So I got it today and drove it for a while without issue.   Go figure.

I hope it is now up to speed, but I can't say that I feel 100% confident.