Any car mechanics in the house?

winbig

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Mar 10, 2005
Location
Pennsylvania
Hey all,

I'm having a weird car problem. I'm about to name this car Christine. It's possessed!

Car in question - 1997 Kia Sephia, 1.8L 5spd stick.

1. The check engine light doesn't stay on all of the time. It'll go off at times, even when the symptoms haven't changed.

2. There's two stages of it acting up:
a) When it's really acting up, the car does not like to idle at all. No matter what you're doing, whenever the car is not in gear, either by having the clutch engaged, or being out of gear altogether, the idle will lope between 100 (yes, 100! :eek:) to 500rpm's. It gets so low sometimes that it will either die altogether, the lights will come on; like it's wanting to die, or it will "wake up startled" and jump up to 1200 rpm, then go back to 500 or less. When it's acting like this, once I reach my destination, shut the car off and get out, it smells like it has an exhaust leak - but there's no leak! Also when this is happening, I will only get 20mpg. The norm for my car is 30; a drop of 1/3.

b) The other stage is on the opposite side of the spectrum. The engine will idle perfectly, but the idle will lope in the other direction - between 750 and 1200rpm. This is where it gets weird. Again, it will only lope out of gear, but only while the car is moving. Once the car comes to a complete stop, it idles a straight 750rpm or so. Once this 'stage' occurs, gas mileage and performance returns to my normal 30mpg. The smell of an exhaust leak is non-existent during this stage.

3. What really surprises me is that when it is doing 2a, if I disconnect the battery for awhile to "reboot" the computer, the car will start doing 2b!!!


When I had the car in for inspection (Dec), the mechanic suggested starting with the mass air flow sensor. This sounds about right, because I'm thinking that the exhaust leak-type smell is from the car running too rich (not enough air). The only thing I'm worried about is spending $200 on this sensor, and come to find out that it's the computer itself. Parts such as this are non-refundable.

I guess the bottom line is: Why does the car run great after a reboot of the computer? :confused:

Thanks for any help! :notworthy

ps: It's in stage 2b right now. I'm going to keep a log of how many miles it takes to start acting up again. So far It's been close to 150 miles.
 
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Win, it sounds like it is burning way too rich...maybe the O2 sensor is going bad, I had similar problem about a year ago and that's what they changed out...

It should only cost you about $50.00 to have them scan the computer codes...then we will know for sure...
 
Hmm, interesting. That one's only $73...:D

This is why I love oldschool cars. Back then if you were running too rich or lean you could fix it with the turn of a screw. Nowadays you have to buy a $200+ part that 1) costs $10 to make and 2) takes about 2 minutes to put on. :rolleyes:

Too bad it's almost impossible to get 30mpg out of a 20+ year old car. I'd love to have another muscle car :D
 
Hmm, interesting. That one's only $73...:D

This is why I love oldschool cars. Back then if you were running too rich or lean you could fix it with the turn of a screw. Nowadays you have to buy a $200+ part that 1) costs $10 to make and 2) takes about 2 minutes to put on. :rolleyes:

Too bad it's almost impossible to get 30mpg out of a 20+ year old car.

Shit, I know what you're talking about man...used to be we could work on our own vehicles but not no more..
 
You know the O2 sensor is the Oxygen sensor and that's exactly what it sounds like is happening is that the fuel mixture is not getting the right mix...backpressure from the exhaust you know...

Yea, it's making sense really. I had the computer codes checked out one time when the idiot light was on, and it came back with something to the tune of having an air leak somewhere, but I checked out all of the hoses and everything and there's no leaks.

I just wish those idiot lights would be of more use and give details and not list 5 things it "could" be.
 
Yea, it's making sense really. I had the computer codes checked out one time when the idiot light was on, and it came back with something to the tune of having an air leak somewhere, but I checked out all of the hoses and everything and there's no leaks.

I just wish those idiot lights would be of more use and give details and not list 5 things it "could" be.

Yea, I know what you mean...I almost freak out on my mechanic everytime he charges me $50.00 for running that five minute computer scan...
 
Yea, I know what you mean...I almost freak out on my mechanic everytime he charges me $50.00 for running that five minute computer scan...

$50?????? :eek:

Head over to AutoZone. It's free, and they'll even write out the codes for you. Take those codes over to Google, and viola - there's the explanations. :thumbsup:


edit: This is getting crazy. I was just going over the codes for my Kia, and found this:

Idle Air Control Valve

:eek:

wtf? See what I mean? It could be many of things. That one is $363.
 
Here's one way to fix it....

Problem solved 100% :D

https://www.casinomeister.com/forums/threads/thank-you-caesars-ac.23206/


Had to, it was getting worse. It's like one of the sensors or whatever would cut off air to the engine altogether or something. Every now and then the car would suddenly jerk for no reason. It'd give you whiplash if it jerked any harder....

And when it would jerk the check engine light would go off, then come back on a few seconds later. It definitely wasn't anything mechanical - purely sensor related. :rolleyes:
 
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Problem solved 100% :D

https://www.casinomeister.com/forums/threads/thank-you-caesars-ac.23206/


Had to, it was getting worse. It's like one of the sensors or whatever would cut off air to the engine altogether or something. Every now and then the car would suddenly jerk for no reason. It'd give you whiplash if it jerked any harder....

And when it would jerk the check engine light would go off, then come back on a few seconds later. It definitely wasn't anything mechanical - purely sensor related. :rolleyes:

That's what I thought it sounded like...I've had so many of those sensor issues in the past with all of my work trucks and such...glad to see you're getting that fine ride you showed us the pic of though...those are real nice cars...my son-in-law has one that looks just like the pic you posted...
 

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