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Discussion Starter #1
2006 kia rio
Sorry if i violate any protocols this is my first post.
Washed the engine and the motor ran very poorly. Put new plugs in even though the old plugs had about 10,000 kms on them. They were changed with the timing belt @ about 80,000 kms. Car then ran perfectly. I started driving a 400 k trip with the car and it started out running reasonably well, then it started getting down on power. I noticed it would go faster if I stepped on the gas less, otherwise it would just bog. After a while the car was down to 50 km’s an hour. Car would start and run perfectly but once it got off the idle circuit it would not run right/ bogging missing popping etc. This is an overfueling or rich condition as verified by smell and removal of plugs. I unplugged the mass airflow sensor and it ran the same. Assumed the MAS was shot so I changed it, now it runs worse and will not idle without me holding the gas on a tich. When I floor it in neutral the motor revs up and down and sounds like it is bogging. It did not throw codes other than the evaporative canister valve one. I am changing it today. Any and all thoughts are welcome.

Take care,

Phil
 

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First thing that comes to my mind is ..."when did you last replace the air filter?"
They get ignored a lot around here. Put a dirty face mask on and try to run...you'll gasp...bog down...but will do "ok" just sitting there.
Just had a guy down in Texas with a Spectra complaining of poor mileage and performance..It was a very dirty air filter.
At 80k kms (48k miles) the catalytic converters and O2 sensors "should" be OK..

You said " I unplugged the mass airflow sensor and it ran the same"...
What is the purpose of a MAF? To read the "air flow". So with little to no flow it wouldn't matter if it was in or out of the "circuit".
The evap valve could also cause a vacuum/back pressure problem with the fuel feed but usually NOT a rich A/F mixture...
Just some thoughts..
Dave
 

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Discussion Starter #3 (Edited)
All of that helps Dave. I was pretty sure there was an idependent idle circit which it runs fine on. I unplugged the O2 sensor in the exhaust manifold and it ran no differently than with it in. It throws no codes but I suspect the O2 sensor and the MAS are not talking to each other. Air filter is clean a good starting poin t but it is in good shape. Anything else come to mind ? Thanks for that dave.



Phil
 

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Discussion Starter #4
A few other things occurred to me as I drove the 400K's back in my pickup. 1. The car now starts and idles smoothly again. It would just idle rough and stall if I stepped on the gas and it was bogging until it would quit. I did not change the eval valve as the one the dealer sent was the wrong one but I did unhook it and once again it had no effect on the way it ran.

Am I accurate in assuming if the Mass Air Flow sensor was not getting the feedback from the O2 sensor it would default to a full rich position?

My line of thinking now is either the O2 sensor is shot and not giving any feedback to the MAS or there is a broken /unhooked wire somewhere in the middle that is not allowing those two components to communicate with each other.

DOES anyone have a schematics for the wiring of the fuel delivery system ?

Thanks for all so far guys! Much appreciated.

Take care,

Phil
 

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Discussion Starter #5
Further Brain Droppings ...

If the timing belt had slipped a tooth. Would it start and idle properly???

Maybe it wasn"t tightened correctly when the KIA guys installed it.. It was misfiring earlier but I suspect it would be very unlikely to skip while driving down the highway ??? An engine mechanical issue would explain the no code situation.

What are other people thinking ???

Thanks in advance.

Phil
 

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Hi again Phil..
The MAF does not "talk" to the O2 sensors...It supplies information to the ECM (engine control module) as well as does the O2 and other sensors... Decisions are made within the ECM and fed to the fuel injectors, spark coils, emission solenoids, and variable valve timing. O2 sensors and the MAF will usually throw a code.

If you have a OBDII scanner that gives real time data (while the car is moving) I'd suggest checking the short term and long term fuel trim readings...
The readings will give information on your air/fuel mixture.

Sure...a timing belt slipping a tooth would cause the problems of popping, and running like a dog.. When I replaced the TB on my wife's 07 Spectra the first attempt.. I had the belt off by one tooth..It started fine but lacked "guts". It also threw a code about VVT (variable valve timing). I just don't think the dealer would have let it go with the TB loose but a bad tensioner would allow it to slip...

Your comment about washing the engine still bothers me..Newer engines don't like being "pressure washed"...too many electronic components and harness connectors to get wet and start corroding... ALSO check the coil/spark plug wire connections for damage... Water and high voltage don't mix well...

Also the comments about it would go better if you were easier on the gas...sounds like it's starving for air (or fuel). Try driving it with the air flow disconnected just after the MAF (going away from the throttle body) ...
Sometimes the "plumbing" they use to route the air can have a low point where water can accumulate...
Dave
 

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Discussion Starter #7
Hi Dave,

THanks for your help and suggestions. I think I have to admit this one is past my skill levels. The next time I get out to our acreage where the mighty Kia is currently sitting, I will have it towed in and let you know what the prognosis is.

appreciatively yours,

Phil
 

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Hi all turned out to be a pluugged catalytic convertor. I cracked the exhaust just below the collector and she runs like a swiss watch again. Oviously will need to fix it properly when i get back home but works for now.

Question if i run it for 400k's at highway speeds will it hurt the engine ? I WOULD LEAVE IT RUNNING WHEN I got to the other end until i reattached the exhaust and warmed the exhaust pipe up to allow the valves to cool themselves properly ie not get the cold draft of air drawn back into the exhaust on to the hot valves. i would of course be taking it easy on the enigne 110 k's kind of thing
 

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If you have the front one bad (Cat).. remove the exhaust manifold (with the cat) and disconnect the bottom going to the exhaust pipe... When it's away from the car use a piece of steel rod and break up the honeycomb inside and dump it out...Re-attach the empty Cat and drive it home... You WILL get a CEL (put a piece of black tape over it) but you will not hurt the engine getting it home...and it WILL run better..
You should remove and clean it out to keep the pieces from plugging the second cat.

Now...How many Miles/KKms are on the car? The best I could figure with what you gave was 48k miles (80k kms)....and I'd want to know WHY the Cat failed at such a low mileage?

I don't know if Alberta Ca requires pollution checks and if not you still have the secondary Cat that basically has been doing very little up till now...

A new front Cat is around $400 (USD) on ebay
Exhaust Manifold w Catalytic Converter Gasket for 06 08 Accent Rio 1 6L DOHC | eBay

and doesn't require major labor to replace it....
Dave
 

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Discussion Starter #10 (Edited)
EMISSIONS stuff is covered for 8 years and 130,000 kms in Alberta. Basically i have to get it to the kia dealer under it's own steam and have them diagnose it and then they will fix it for free.

Problem is I need to drive it home, 400 k's to drop it off. I was curious as to whether or not it would hurt the engine if I drove it with the exhaust loosened after the initial cc just after the collector. I need to reduce backpressure so it can run well enough to get me home.


Thoughts ???

Take care,

Phil
 

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The exhaust gases are very hot and that "leak" might melt or cause a fire under the hood.
It will probably damage the gasket going that far also.
Got any salvage yards close by where the car is located? Maybe you could get a "bad" cat that you could gut and then "sub" in to get you home..? How about a KIA/Hyundai dealership where it's parked? Get a local muffler shop to build you a "test pipe"
Dave
 

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Discussion Starter #12
Hmm all good thoughtful points. most of which had not occured to me. If I am reading this correctly you don't think there is a big risk of engine damage assuming I don't drive like a dufo. I will crawl under it today and see what \i can see. Those are all grea solutions but \i am on the road perse and do not have the time available to run the solutions you have suggested.

In Alberta and possibly Canada it is illegal to sell a used cat as there was a rash of people stealing them and selling them. \but i will see if I can apply one of your other proposed solutions.

\thanks for your thoguhts and support in this matter.

Take care,

Phil
 
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