My Kia turns itself off as I'm driving

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2005 Kia Optima 2.4 L 4 Cyl with 97,xxx miles This is a weird problem that's been happening for two years now. Why have I let it go for two years? Because, oddly, it's seasonal. It will happen in the autumn and the spring. All I can figure it it's temperature related somehow, as it happens when it's chilly (like 50ish) but not warm/hot or cold. There are no CEL's What happens is I'll be driving and the car will shut off. The tach drops to 0 and I loose all engine-powered features, such as power steering and power brakes. It's as if I turned the ignition back to the ACC position from the ON position. Depending on speed, the car will usually start back up. But if I'm going slow (like backing out of a parking spot or pulling into traffic) it will roll to a stop and then I'll need to crank it over with the starter. I have no idea where to start. The ignition is on my list of suspect parts. My mechanic thinks the crank sensor. But from the lack of CEL I'm doubting that. But he is a mechanic and knows more than me. From reading various forums it seems like people are having a similar problem that traces back to the main relay, but all of them have been with Hondas and Mitsubishis. Right now I'm at a loss. Now that the weather is cooling off, I'm looking into troubleshooting it. It's so intermittent that the mechanic hasn't found anything, but it's dangerous enough that I need to fix it. If anyone has any troubleshooting tips, I'd really appreciate it. I don't want to randomly start replacing parts but I need to take care of this!
 
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Nick1994

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How are you still alive!? What about all those killed and injured from GM ignition switches turning the cars off!? Lol I had a 96' Chevy truck that would do this and would fire right back up, it was the fuel pump relay that the connection was loose underneath the fuse panel and it kind of melted the relay, popped in a new one and cleaned up the connection and it worked great.
 
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You're not at a loss at all. And it is dangerous enough you need to fix it. You have three obvious sources, start there. I'd guess the ignition switch but if the relay or the crank sensor is cheap you might start there instead. Couldn't you replace all three for 200 bucks on a Saturday morning?
 
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How often does this happen? How does it start back up? Does it start up when you give it some throttle while the car is rolling? Maybe its something like your idle control being a little slow to react. Spring and fall are times where the climate control are used less, maybe the default bump in idle keeps it from happening in the summer and winter when these things are left on. Just guessing here.
 
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If it has a throttle cable, you may have a failing Idle Air Control valve. If it's drive-by-wire, there's any number of possibilities. ECU, one of the car's many sensors failing, etc. My '99 Explorer did this same thing until I replaced the IAC valve.
 
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I have 06 with the same engine. It happened to me a few times also. When it first happened the code reader read 'crankshaft sensor' , paid 450 to have it replaced. Not sure if that was the problem or if it was cable /connections issue but I had not been able to restart after a while at all. Previous to that I had the timing belt replaced. I think they touched the sensor, it got loose maybe... Fast forward 2 years to spring. It experienced fluctuating rpms with no turning off fully. And that was misfire. Replaced spark plugs and 2 wires, since then thankfully it has not repeated the problem. Now it has 104k miles on the odometer.
 

Smcatub

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The crank sensor is cheap, but it's a huge PITA to replace - you have to take the timing belt off to do it, and the timing belt burred under a bunch of other stuff. I have no idea how to get the main relay out. It's bolted to a metal frame under the dash, and I could not figure out to get the interior disassembled enough to get to the bolt. Maybe I'll just have to drill a hole in a trim panel to get to it.
 

Smcatub

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Originally Posted By: JamesBond
How often does this happen? How does it start back up? Does it start up when you give it some throttle while the car is rolling? Maybe its something like your idle control being a little slow to react. Spring and fall are times where the climate control are used less, maybe the default bump in idle keeps it from happening in the summer and winter when these things are left on. Just guessing here.
It happens with no rhyme or reason. I've been doing anywhere from 2 MPH to 70 MPH. It doesn't stumble or anything, just an instant shut off. I hear a click on the interior when it happens, not sure what it is. I can give it any amount of throttle and it doesn't seem to make a difference. Would the idle valve be a suspect if it happens when I'm driving, with the throttle open?
 

Smcatub

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The timing belt was replaced before this started happening, but there was about a 15-20k mile & month (I do about 1k per month) gap between the timing belt and the problem starting.
 
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Crank sensor. We see it often on this motor. Sometimes if the timing belt shears a tooth it can take out the crank sensor. In order to change the crank sensor, the power steering pump has to be moved and the timing cover pulled. May as well change the timing and balance belts while you are in there.
 
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[/quote] Would the idle valve be a suspect if it happens when I'm driving, with the throttle open? [/quote] I wouldn't think so if you've got the throttle open, I was thinking more like when you are on and off the throttle.
 

Smcatub

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Originally Posted By: JamesBond
Originally Posted By: SmcAtUb
Would the idle valve be a suspect if it happens when I'm driving, with the throttle open?
I wouldn't think so if you've got the throttle open, I was thinking more like when you are on and off the throttle.
Ok, thanks. I'll try to pay attention to the throttle position next time.
 

Smcatub

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Originally Posted By: salv
Crank sensor. We see it often on this motor. Sometimes if the timing belt shears a tooth it can take out the crank sensor. In order to change the crank sensor, the power steering pump has to be moved and the timing cover pulled. May as well change the timing and balance belts while you are in there.
Ok, tonight I'll inspect the wires to make sure they're OK. If not I'll try to patch them up. If they look good I might just replace the sensor and hop that's it. The current timing belt has 40k miles. So it's not due but it's got a little age on it; maybe I'll just replace that and the balance belt along with the crank sensor.
 
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Originally Posted By: Smcatub
Originally Posted By: salv
Crank sensor. We see it often on this motor. Sometimes if the timing belt shears a tooth it can take out the crank sensor. In order to change the crank sensor, the power steering pump has to be moved and the timing cover pulled. May as well change the timing and balance belts while you are in there.
Ok, tonight I'll inspect the wires to make sure they're OK. If not I'll try to patch them up. If they look good I might just replace the sensor and hop that's it. The current timing belt has 40k miles. So it's not due but it's got a little age on it; maybe I'll just replace that and the balance belt along with the crank sensor.
5yrs/60k replacement interval for Hyundai and Kia on timing belts.
 
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Originally Posted By: Smcatub
2005 Kia Optima 2.4 L 4 Cyl with 97,xxx miles
Don't all Kias have a ten year/100k warranty? Let them deal with it. After a few times, if they don't fix it, lemon law it.
 
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Originally Posted By: Zeus33
Originally Posted By: Smcatub
2005 Kia Optima 2.4 L 4 Cyl with 97,xxx miles
Don't all Kias have a ten year/100k warranty? Let them deal with it. After a few times, if they don't fix it, lemon law it.
Lemon law on a 9 year old car?
 
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Originally Posted By: Nate1979
Originally Posted By: Zeus33
Originally Posted By: Smcatub
2005 Kia Optima 2.4 L 4 Cyl with 97,xxx miles
Don't all Kias have a ten year/100k warranty? Let them deal with it. After a few times, if they don't fix it, lemon law it.
Lemon law on a 9 year old car?
10yrs/100k is powertrain only, and only counts for the original owner. The 10/100 is not transferable. The bumper to bumper warranty is 5yrs/60k. All sensors, emmissions, and fuel system components fall under the 5/60 warranty. 10/100 covers engine, transmission, water pump, crank pulley, wheel bearings,cv axles, valve cover gaskets, cam and crank seals, oil pan (not corrosion). Pardon me if I missed something.
 
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My ranger did this, had a kinetic shut off fuel switch on the passengers floorboard I had to press to get it to start again
 
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Actually in some states the timing belt counts as an emissions part and is warrantied up to 10 years and or 120k miles. OP this is very serious, if you can't figure it out soon find a competent mechanic to fix it!
 
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