[spitfireap]

I've owned this 2004 Sedona EX for a year (83K miles) and it's done this on and off since I got it (mostly on). When the AC is on and I'm in idle, reverse, or at slow speeds during acceleration, the car will hesitate/stumble intermittently and randomly. It is of short enough duration that I really don't lose too much power but I can see the RPM needle dip a little. Once I pick up a little speed (probably over 10 mph) the problem is gone or at least I cannot notice it. Occasionally if I'm stopped it'll cause the body of the van to move - won't make the wheels move, but I can feel the body moving. It happens most of the time, in hot or cold weather and any air conditioner setting. If I turn off the AC, the car runs normally. There is no check engine light on. Any help would be appreciated.

 

[spitfireap]

No replies to this old post but the van is still doing this. Any insights?

 

[Wry 'Cuda]

Most cars will react slightly when the AC cuts in. One after-markey kit I saw had a solenoid to bump up the idle speed when the compressor was pumping.

 

[jlps]

Check the battery terminals, Kias oem terminals oxidize and even though they look mint, the need to be replaced because of the oxidation you can't see that is inside the crimped on part of the terminal on the copper wire. This has caused alot of weird electrical problems ( stumbling, stalling, idle problems, flickering lights etc. ). Also, sand down the grounding wires in the engine compartment. Kia had a problem where the factory put grounds on top of painted metal and used anticorrosive screws ( the anticorrosive coating did not conduct electricity ). Effectively the grounding was useless.

 

[Chesney]

May be worth checking the idle speed too. The AC will drain power from the engine if the idle is too low, then the engine will struggle to run the compressor

 

[spitfireap]

Tried the battery clean

Jlps,
Thanks for the info on the battery terminals. I pulled off the terminals and noticed a lot of corrosion on the positive one. I cleaned everything off and brushed down the cable itself where it was crimped on. Hooked everything back on but the problem persists. It still only happens when the A/C is on and the car is in drive or reverse - does not happen in neutral.

One plus of the terminal cleaning is that the brake lights or radio don't seem to cut out anymore when the brake is applied. I haven't traveled much after the cleaning so I'm not sure that problem is completely gone, but it seems to be. I've seen cars with random misfires, check engine light, and P0300 code that look a lot like this. My van, however has no check engine light on. I'm gonna try to sell this van soon, but would like to have this problem fixed before I do. Any more ideas on what might be going on?

 

[jlps]

I am glad it helped. I have to repeat part of my last post - the mild corrosion that causes the real 'pain in the but' electrical problems is inside the crimp where the battery terminal actually is crimped on to the wiring harness. You cannot wire brush this. I have had to split the crimp on both the negative and positive terminals on two different Kia Sedona's . I then wire wheel cleaned the inside of the crimp, wire wheel cleaned the bare wire, recrimped the terminal onto the wire, and then finally soldered it to prevent it from corroding again. The oxidative corrosion was a white film that did not look too bad - until I scraped it off to expose shiny metal. I am not kidding when I say that all of my weird electrical problems were solved instantaneously, including the radio / interior light flickering / headlight flickering / brake light / stumbling / stalling under load issues etc. An easier fix would be to cut off the existing battery terminals, expose some fresh shiny wire, and put on two new aftermarket terminals from an auto parts store.
Also, CLEAN THE GROUNDS on the engine firewall. Re read my last post. You need to sand or grind the paint off from under the grounding wire terminals on the firewall. I think I did 4 or 5 of them , one of the grounds comes directly off of the negative battery terminal. This also made a huge difference in the perfomance of the Sedona when it was run under load ( like with the ac on, or in drive or reverse ) . Good luck. If the grounding and the crimps do not solve the hesitation / stumbling under load, put another post up and let us know. There are some other things to look at AFTER doing the terminals and grounds.