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Discussion Starter #1
Hey All, hope you guys and gals can help. Replaced my timing belt and CKP on my 05 Optima 2.4L. Everything went great, took 3 tries but I finally got it, fired right up. The car runs like a top. My problem is it starts up nice, cold idle kicks in and it sounds good. As soon as the cold idle turns off and it steps down to normal idle it runs rough, not crazy rough almost like a flutter but noticeable. Cleaned the MAF and it seemed to get better but it is coming back a little. Any ideas would be appreciated.

thanks,

Robert
 

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Greetings,

Assuming you have re-checked your work / the timing is spot on,

And discounting any tune-up / maintenance items (plugs/wires/fuel filter/air filter),

I would try cleaning the MAF a second time: always be careful when handling the MAF: do not touch the vanes inside the MAF, they are fragile, spray down with MAF cleaner, and let the MAF -completely dry- before reinstalling,

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Illegal air entering the intake system after the MAF -> the throttle body can cause idling issues, so would recheck all ducts & clamps to make sure they are in good condition and secured properly,

A dirty IAC (Idle Air Control) valve, or illegal air entering through a damaged IAC valve gasket, can also cause idling issues,

A visual check of all vacuum lines and/or plugs on the Intake Manifold would also be a good idea, hoses should be in good condition/pliable/not cracked, port plugs should be intact/not cracked/fit to vacuum port snugly..

Hope this helps,
GottaCruise
 

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Does the rough idle seem to be only happening since the TB replacement? Checked items that were disconnected during the job?
 

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Discussion Starter #4
Thank you guys both for the responses it is very appreciated. GottaCruise, everything else has been replaced that you mentioned I did a complete tune-up when I did the TB. new plugs , new fuel filter, new air filter, oil and oil filter and new serpentine belts up front. I did not replace the HT leads though??? I will check all hoses for vacuum leaks as I realize stolen air is a big problem. I will also check the IAC as well. Wry'cuda. i do not know about pre-TB as this was an auction purchase and it was not running at the time i bought it.

thanks again guys
 

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Hi Robert,

Congrats on your purchase,

From your post, it sounds like you are doing the right work to the car to get rehabbed / QA'd back as a daily driver,

re: HT leads, anything's possible: but if the car is performing well at cold start (ECM Open-loop) vs. warm (ECM Closed-loop), I'd be hesitant to say they are the cause. But if you have the tools (multimeter), it wouldn't hurt to check the resistance values of the wires and coil packs in any case.

If after rechecking items around the TB as Wry 'Cuda recommended does not improve the issue, then (if it was me) I would start scrutinizing sensors..

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Idle issues when the ECM is in closed-loop (warmed to operating temp., the ECM begins using sensor values for engine management) would indicate a input sensor reading/a sensor issue/or related wiring, illegal air entering past the MAF into the intake system, or an issue with the Idle Air Control valve, which actively meters air into the throttle body, based on sensor input..

Sensors used in active closed-loop ECM engine management include: the Engine Temp sensor, the Air Intake sensor, the MAF sensor, the Throttle Position Sensor, and the primary (B1S1) O2 sensor..

If you have the ability to hookup a live data scanner which can read those sensor values at time of engine operation, that may help to narrow down the cause of the issue - for a low-cost ( Laptop-based / USB ) data scanner, see my sig.,

Testing the expected (electrical) values of each of the sensors (voltage/resistance) may also help narrow down the cause of the issue:

if you haven't already, recommend signing up at the kiatechinfo website (see my sig.), using Internet Explorer web browser (Note: for IE versions 9 and above, add the kiatechinfo website to the "compatibility list" of IE for proper website display) - once registered you can view the [Service Info] for your vehicle / the diagnostic info & expected readings for testing,

Hope this helps,
GottaCruise
 

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Discussion Starter #6
Hey Gotta Cruise,
these are all great pieces of info to put me back to right.

I believe I got the TB stuff all put to bed and I would hate to take all that apart to see if it is. The only thing I was unsure of as I was doing the belt was the oil pump part . Where you insert the screwdriver to keep it form rotating. I am not sure I did that right but I have oil pressure and no noises from the motor. I do not have a scanner, YET, so I am wondering if I should just start replacing some sensors to see where it gets me.

TSP then MAF and so on. Probably not the smartest approach, I am sure. Also a big thing yesterday I drove the car and noticed a significant hesitation when I hit the accelerator to say pass another car.. Does this help me to refine my troubleshooting to the TSP.

Look forward to hearing from you.

Thanks again.
Robert
 

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Hey Gotta Cruise,
these are all great pieces of info to put me back to right.

I believe I got the TB stuff all put to bed and I would hate to take all that apart to see if it is. The only thing I was unsure of as I was doing the belt was the oil pump part . Where you insert the screwdriver to keep it form rotating. I am not sure I did that right but I have oil pressure and no noises from the motor. I do not have a scanner, YET, so I am wondering if I should just start replacing some sensors to see where it gets me.

TSP then MAF and so on. Probably not the smartest approach, I am sure. Also a big thing yesterday I drove the car and noticed a significant hesitation when I hit the accelerator to say pass another car.. Does this help me to refine my troubleshooting to the TSP.

Look forward to hearing from you.

Thanks again.
Robert
Hi Robert,

Greetings from snowy NH... Glad it's spring again.. ?!#@! :)

I read your post, best answer I can give you at this point is if you are unable or unwilling to do the sensor testing yourself, then I would STRONGLY recommend you bring the car into a dealer or shop with the proper equipment to do the testing..

Guessing and replacing sensors randomly won't diagnose the specific issue, and can get EXPENSIVE, real quick.

I'd rather see you get the issue properly diagnosed and corrected, vs. replacing (nn) sensors only to find out it was none of those / or the last sensor. The $$$ spent on a quality diagnostic will either be a wash or save you $$$ in the long run.

Seeing as the vehicle was an auction purchase, it may well have had this issue prior: bank/dealer repo's that have any "strange" issues are usually consigned to the auction block (vs. on the lot as used car sale).

Best to either do the "detective" work yourself and save some money, or have a (Kia) certified ASE technician that has experience w/ your vehicle do the work.

Just make sure you discuss the issue w/ the Service Mgr. (and tech if possible) when you bring the vehicle in, be honest about your budget, and the amount of $$$ it will cost / you are willing to spend to have the diagnostic service(s) done, so you and Service Dept. are on the same page / can intelligently discuss what diagnostics they will do and the fees involved.

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In short, rather than randomly replacing parts, recommend doing or getting the diagnostics done needed to effect a good repair,

Regards,
GottaCruise
 

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Discussion Starter #8
GottaCruise,

to be honest I have to agree with you, you make a good point the KIA dealer in my area is charging, I believe, 100 bucks for complete diagnosis. Which is probably the cost of one or two sensors. I think it best to just bring it over, test it and then fix it myself.

I really need to buy a scanner, maybe with the profits form this sale I can get a Genisys or Autel off of EBay?


Regards ,
Robert
 
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