Engine surges when maintaining speed.

[heyrobb]

Anyone know how to deal with this problem: Engine surges when trying to maintain a constant speed (try to hold 60 mph, it will surge to 62, drop back to 60, then repeat the surge again every minute or so). Dealer had no luck locating a solution. 2004 Sante Fe LX 3.5L with auto climate control, 500 miles, only does it with A/C on, doesn't do it with cruise control on. Dealer says it might just be the "normal" cycling of the A/C compressor, but it is very noticeable and annoying, too noticeable in my opinon to be "normal". Does anyone here think this sounds "normal" (I'm afraid that I won't be able to get used to it, I've never had a vehicle act like this simply because of the A/C). Any ideas would be greatly appreciated.
Thanks,
Rob.

[HYUNDAIPARTS]

My 2004 LX with the 3.5 does not do what you claim, this is not normal. I would have them talk to tech line about this problem. I have noticed that since the module to fix the bump-stop symptom was replaced the engine does seem to run smother. Have you been at a stop and your vehicle jumps or it feels like you just have been rear ended? Or the other symptom was it feels like its binding when going in reverse. There is a fix for that. I have not seen any of the symptoms that you are speaking of. I would get them to dig a little deeper.

DK

[twospirits]

I do believe there is a TSB about this that I saw on the Hyundai Webtech site, but I can't get in it here at work.

[heyrobb]

Originally Posted by twospirits

I do believe there is a TSB about this that I saw on the Hyundai Webtech site, but I can't get in it here at work.

Hi Twospirts, I haven't been able to find the TSB, can you give me any more info?

[twospirits]

The TSBs I was referring too are the following...which Hyundaiparts mentions the fix for. But I still do not think they fully apply to your problem. Like Hyundaiparts said, I would really make the service dept look further or call techline to possibly see if this is a new problem worth of getting a tsb in the future.

TSB 04-36-012
2003-04 Santa Fe Improvement of initial acceleration

TSB 04-40-003
2003-04 Santa Fe Bump/jerk after vehicle has stopped

TSB 04-40-007 2001-04 Santa Fe Damper clutch shudder

TSB 04-40-008 2004 Santa Fe Driveline bump

All are available on the website (www.hmaservice.com):

They should still call Techline if they any questions if they do not see a suitable tsb for your problem.

[equus]

Originally Posted by heyrobb

Anyone know how to deal with this problem: Engine surges when trying to maintain a constant speed (try to hold 60 mph, it will surge to 62, drop back to 60, then repeat the surge again every minute or so). Dealer had no luck locating a solution. 2004 Sante Fe LX 3.5L with auto climate control, 500 miles, only does it with A/C on, doesn't do it with cruise control on. Dealer says it might just be the "normal" cycling of the A/C compressor, but it is very noticeable and annoying, too noticeable in my opinon to be "normal". Does anyone here think this sounds "normal" (I'm afraid that I won't be able to get used to it, I've never had a vehicle act like this simply because of the A/C). Any ideas would be greatly appreciated.
Thanks,
Rob.

have them to initialize the ETS system and then reset the adaptive learnt numbers on the APS and TPS...since this 3.5 is drive-by-wire it is possible that the ETS motor initialization was never performed....you are very observant in the surge speed....60 to 62....!!!! Also there is a TSB that tells the Tech to do the Re-learn procedure...tell them to use the XG350 TSB for that as it applies to this SM also...

[andrew348]

equus

Question : in the 3.5 fly by wire . In order to compensate for the load of the ac system does the pcm move the throttle plate or the idle air control motor .

other thoughts do we have a full charge on the ac system IF the charge is low the rpm drop may be noticed due to excessive cycling of the a/c compressor clutch
If resetting the ets system does not do the trick .
1) check the cable to the ets module did it come out of the metal bracket causing a flcuation of the tps / aps signal

2) if the pcm does in fact increase the idle air control and not the tplate do we have a lazy iac motor . (not sure about this one i will check tomarrow)

3) I would like to see somthing . Drive the vechicle and take note of the rpm at 60 mph . pull to the side of the road or in your driveway at home and in park or nuetral try to acheieve the prevously noted rpm with ac on is there a rpm change when the ac clicks on and off .if so aproximatly what is it write back and tell me what the rpm is and check my fathers santafe . also in 60 seconds how many times does your ac compressor click on and off note test this when the engine is hot and rpm at 1500 on park .

[equus]

Originally Posted by andrew348

equus

Question : in the 3.5 fly by wire . In order to compensate for the load of the ac system does the pcm move the throttle plate or the idle air control motor .

other thoughts do we have a full charge on the ac system IF the charge is low the rpm drop may be noticed due to excessive cycling of the a/c compressor clutch
If resetting the ets system does not do the trick .
1) check the cable to the ets module did it come out of the metal bracket causing a flcuation of the tps / aps signal

2) if the pcm does in fact increase the idle air control and not the tplate do we have a lazy iac motor . (not sure about this one i will check tomarrow)

3) I would like to see somthing . Drive the vechicle and take note of the rpm at 60 mph . pull to the side of the road or in your driveway at home and in park or nuetral try to acheieve the prevously noted rpm with ac on is there a rpm change when the ac clicks on and off .if so aproximatly what is it write back and tell me what the rpm is and check my fathers santafe . also in 60 seconds how many times does your ac compressor click on and off note test this when the engine is hot and rpm at 1500 on park .

There isn't any IAC motors with this system....Throttle Plate movement is directly proportional to APS readings (APS..Accelerator Position Sensor)...load compensation is done thru Injector PWM and control of timing....if VSS is inactive then the throttle motor is used to maintain target idle....if the AC is low on refrigerant the Triple Pressure Switch will not change Voltages and the PCM reads that as to disable AC clutch relay....it is an initialization problem...the battery NEEDS to be checked....if the B+ has been lost for some reason in the past few weeks PCM needs a reference point of throttle plate to maintain idle.....hence this surge with AC on...
cable from the Cruise Controller to APS will not cause this concern as the APS is the redundant reading once the TPS is active (TPS is the feedback for the PCM to know if the command to the ETS motor worked)...still that(APS) sensor communicates with PCM to denote Driver Command.....it would not hurt to check the cable.....make sure it is not tight.....

[gph303]

Originally Posted by HYUNDAIPARTS

My 2004 LX with the 3.5 does not do what you claim, this is not normal. I would have them talk to tech line about this problem. I have noticed that since the module to fix the bump-stop symptom was replaced the engine does seem to run smother. Have you been at a stop and your vehicle jumps or it feels like you just have been rear ended? Or the other symptom was it feels like its binding when going in reverse. There is a fix for that. I have not seen any of the symptoms that you are speaking of. I would get them to dig a little deeper.

DK

I'm interested in the bump-stop symptom cure as I have a 2001 Toyota Tundra v8 4x4 that has a very similiar problem. Also having surging problems on light accleration and sometimes sluggish operation. I've not been able to find anyone on the tundra website with similiar problems. Just curious if it may be a similiar fix for me. Thanks!