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My engine, 2001 Sonata 4cyl. (101,000) bogs when accelerating moderately from a dead stop. It's much worse when the engine is cold. So far the dealer has replaced all sensors possibly related to this issue (according to them) including Mass Air Low Sensor and Throttle Position Sensor. They have also flushed the fuel injectors and de-carboned the intake manifold and pressure checked the fuel system, changed the fuel filter, installed new plugs, wires, and coil. No problem lights during diagnostic. Now they want to change the timing belt (50,000 miles), Balance belt, Crank sensor and Crank blade. These last four items do not seem like a possible cause for the engine to bog only when accelerating and especially worse when cold. What do you guys think? Thanks

 

[jsinton]

They could rule out the timing belt and balance belt by doing a timing belt inspection. 50K is pretty close to needing a new one, but I'd want to be sure it would work before I let them do that. Could be a crank sensor problem, but I'd expect a check engine light if that was so. Maybe the crank blade has a crack, but that would be unlikely... but it would explain the problem.

Sounds like these guys are parts changers, I supposed you have paid for all the previous work, which did not fix the problem. Didn't they guarantee the work? Sounds like you're a goldmine for them and they want some more.

 

[sbr711]

Verify the belt is in correct time.. They (2.4) like to jump, look at upper cover and verify the the cover has the "bump" inside by the exhaust cam gear to help prevent belt jump..

Other item to verify is catalyst is not restricted.. when you hammer the thrrottle, doe it make a loud WHAAA sound under the hood ?

 

[[email protected]]

They replaced the timing belt cover. When I hammer it from a dead stop the engine bogs badly, especially when cold but makes no unusual sounds. They said the converter was good. The engine runs perfect except for this bogging problem. At speed the engine drops into passing gear smoothly and accelerates promptly.

 

[[email protected]]

Just a quick update. The dealer replaced the timing belt, balance belt, tensioner, crank sensor and crank blade. As I suspected, the engine still bogs badly immediately upon acceleration, even when in park. Computer was flashed. Further diagnosis is continuing at the dealership at no charge to me. I imagine they'll say I need a new computer. This has truly been the Sonata from ****.

 

[hyperlexis]

QUOTE (inazsully @ Aug 2 2010, 02:42 PM) index.php?act=findpost&pid=346699

Just a quick update. The dealer replaced the timing belt, balance belt, tensioner, crank sensor and crank blade. As I suspected, the engine still bogs badly immediately upon acceleration, even when in park. Computer was flashed. Further diagnosis is continuing at the dealership at no charge to me. I imagine they'll say I need a new computer. This has truly been the Sonata from ****.

OMG this sounds insane! How much money has this dealer charged you for all this work?!?!?! They sound like they are milking every drop out of you. The car isn't even worth this much money. Have they done a compression test? It is absolutely, positively inexcusable that they have not been able to properly diagnose and repair this after all this time and money.

One thing that I had been consistently disappointed with with my Sonata has been the hit-and-miss nature of different dealers' service departments. I've had instances where I had work done by dealer X, only to be later told by dealer Y that the work was done improperly, or wasn't needed. My clutch had to be replaced three times because of this. Hyundai really needs to work on their dealer service quality. People go to a dealer for the proper fix, the first time, and that's why they get paid such a premium. Terrible what your dealer has done in your situation.

Has your Hyundai district service manager been called in for help at this point?

 

[isreid]

Hi, I have an issue very similar with my 2001 Sonata 2.4L with like 300,000kmh on her.
ive replaced o2 sensors and throttle position sensor, and when im in park as well, always worse when cold, accelrating or reving up the engine has a hesidence to it, and ive even had it accel by itself. Im convinced its my TPS for my issue but like ill post for myself in a minute with my issue, I need to know the correct voltage. it says .3-.9 mV for the blue wire to black/white wire on the 4 pin TPS. im curious, probe with a multimeter yourself the blue and black/white wire and tell me your reading if u can. Mine did that when it was too low, and i have no experienced any engine light come on. but i can move the sensor and change the idle speed so drasticly with bearly a movement of the sensor. when i check shopkey5 for the volts it says 300-900 mV and that range is just to **** large. 450 mV - 600 mV seems to be working better but i need to get the exact number it seems. id love to know what it is.