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Old 1st November 2010, 12:17   #46
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  • Check the O2 sensor(?).
  • Check the fuel quality. IF you have filled from unknown place recently, try filling up from regular known bunk and see if that shows any difference.
  • Throttle body as others as mentioned already.
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Old 1st November 2010, 21:01   #47
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This does not happen consistently. It has happened only twice in last 3-6 months. Within last two days it has not happened again.

The last time it happened was after refill from a pump meant for bikers.

Last edited by sreenivass : 1st November 2010 at 21:02.
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Old 1st November 2010, 23:10   #48
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I believe its the throttle body.
Since you have gotten it cleaned, observe if the issue persists.

You could try the other options mentioned above, if it persists.
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Old 3rd November 2010, 21:26   #49
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Car came back from workshop today, the suspect is supposedly spark plugs. All the 4 have been replaced with new ones, I have to wait and see if a similar thing happens in the next couple of months.
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Old 4th November 2010, 13:29   #50
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The same thing happened to me during my Xeta days. The issue was that, if AC is running and if I try pressing the clutch, rpm just shoots to 2000+ and then settles down. The moment I switch off AC, the issue will be gone. Notified this to the A.S.S a couple of times, but they never had an answer. I also noted that the issue will be severe if the engine is hot.
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Old 5th February 2011, 15:18   #51
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Default Erratic RPM in Fiat Petra

The RPM of my Fiat Petra, is very erratic for last 3 months, but mechanic (Tata-Fiat Authorised Dealer) was not able to solve the issue. After going thru similar issue in TBHP, I advised the mechanic to Clean TB which he did promptly in front of me but Problem not solved.
Even the EXAMINER didn't show any issues.

Today there was another Petra in the Service Center and I happened to visit the Service Center and mechanic suggested to temporarily replace my TB with that of other Petra, just to see if it works fine or not!!! And Yes the problem is my Petra's Throttle Body. My Petra Engine was running smoothly without any issues with the other Throttle Body. So ultimately the problem is identified as my Throttle Body which needs replacement.
I was told by Mechanic that Throttle body is readily not available and it has to be Ordered and it will cost around Rs. 15,000/-.
Is it that costly? Any idea?

Also Mechanic told there is a slight sound/noise coming from TAPET. He said its OK as of now need not work on it, but he said, if I need to fix it, it may cost around Rs. 6000/- (16 Tapets X Rs. 390).

So Gurus, tell me, abt these two things. Is it worth Spending? Is it right spending?
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Old 18th December 2012, 12:56   #52
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Default Curious Case of Rising RPMs

Hi All,

I'm facing a really strange problem with our Accent. Here are some details of the vehicle:

Make: Hyundai Accent
Fuel: Petrol
Model/Year: GLS/2001
ODO: 39770
Usage: Fairly low running, avg of 10km per week.

Ok here's the problem: While driving about in ordinary traffic (where I get to travel around 40kmph), the car behaves fine. However, as soon as I hit Bumper2Bumper Traffic, and I switch to 1-2-3-2-3-2-1-2-3-2-3-2 etc. gears to move around, I noticed that the RPM of the engine keeps building from 1000 to 3500 RPM when the clutch pedal is pressed while changing gears - this happens even when my foot is COMPLETELY off the accelerator. I also tried to put the car in Neutral and even when its in Neutral, the RPMs keep building.

When I remove the foot from the clutch pedal and am in gear, the RPM subsides to a more regular 1500-2500 range and it rises and falls in accordance with the accelerator pedal henceforth while driving in gear and when my foot is off the clutch.

Again, when I approach an intersection / heavy traffic /turning, when I press the clutch and change gears, in the 2-3 seconds it takes to do this, the RPM is already @ 3000-4000 mark and the engine is revving so much that it sounds like its gonna rip itself off its mounts. I slowly lift off my left leg from the clutch pedal and the RPM is back to normal ranges.


I have discovered a way to overcome this madly revving engine - I put the vehicle in Neutral and pump the clutch about 5-10 times rapidly. This solves the problem momentarily and I can put it in the proper gear and drive on - only until the next "gear change" takes place - and we're back @ 4000 RPM.

I am not sure what's going on. Also, another thing I noticed that's strange. This never used to happen before, and am not even sure its related to the above problem. The 3rd gear behaves in a mysterious self-propelling way. I put the car in 3rd gear (going at around 30-40kmph) on a smooth flat road and lift my foot of the clutch... and even my right foot off the gas - I can see that the car is being self-propelled in the sense that somehow, the car keeps chugging along without slowing down, and maintains a good 1200-1800 RPM. No lugging whatsoever - and it feels like someone indeed has a foot on the accelerator and is pressing it constantly and consistently to keep it moving.

This does not happen on other gears on the same road - it slows down gradually until it's at the threshold speed/RPM for that gear and starts jerking and lugging.

I'm not sure if both these problems are related. I would like to have some knowledge about the problem from experts on this forum, before I venture into the Hyundai A.S.S. for a "blade" treatment. As the car is also approaching the 40000 mark, I'm sure the SA will insist on a 40K service and will replace many things as mandatory maintenance.

The clutch-gear thing is my main concern. I am wary of clutch "overhaul" and "clutch plates need to be replaced" scams through other threads on this forum, I just need to be absolutely sure if its the clutch thats causing the problem and not anything related to the transmission/engine.
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Old 18th December 2012, 13:26   #53
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Default Re: Curious Case of Rising RPMs

This is perfectly normal. You can use the search feature on Team BHP and will see similar threads.

The ECU holds the revs for you while you change gears so that you donot get jerks from the engine. take care
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Old 18th December 2012, 13:41   #54
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Default Re: Curious Case of Rising RPMs

I beg to differ from what planet rocker says, I don't think this is normal, rev hold is something that keeps engine rpms from going back to idle when you let off the throttle in between gear changes, It is not normal for revs to build up by itself during gear changes.

vsatyap what are the temp readings like when this problem occurs? if low then, the engine is simply trying to get warm, but if the problem occurs even while in optimum temp, then its an issue.
I would suggest you get your car checked up with your service center and clear up the issue asap. cheers.
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Old 18th December 2012, 13:56   #55
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Default Re: Curious Case of Rising RPMs

vsathyap, I had a similar problem in my Accent 1.6 GLS, but I used to observe it happening more in the mornings than at nights. Don't ask me why . I had similar symptoms to what you mentioned, when my car was at 40k kms age too, and you might be happy to hear this - NO, it didn't turn out to be a clutch overhaul or any such scary expense.

I'm not sure how different your case is, but for me they cleaned the throttle body and this fixed the problem. Advaith Hyundai (Sarakki, JP Nagar) did not charge me for this, and were kind enough to attend to the problem immediately. Please check with your regular service advisor on this possibility.

Quote:
Originally Posted by msaudf View Post
vsatyap what are the temp readings like when this problem occurs? if low then, the engine is simply trying to get warm, but if the problem occurs even while in optimum temp, then its an issue.
msaudf, even if the engine was trying to warm up, it shouldn't be rising to the tune of 3500 rpm. That is way too much .

Last edited by KarthikK : 18th December 2012 at 14:00.
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Old 18th December 2012, 14:01   #56
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Default Re: Curious Case of Rising RPMs

Quote:
Originally Posted by KarthikK View Post
even if the engine was trying to warm up, it shouldn't be rising to the tune of 3500 rpm, that is way, way too much .
I agree Karthink 3500 rpms is way too high for warming up. I think it would create more damage than any good to the engine, i've seen scenarios where the engine keeps revs up to 2000 rpms during initial stages of the warm up.
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Old 18th December 2012, 14:16   #57
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Default Re: Curious Case of Rising RPMs

is it not normal? oh! thats bad! may be i need to check the 2 Hyundai-s in the family with the exact problem with HASS! Thanks for the Tip
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Old 18th December 2012, 14:28   #58
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Default Re: Curious Case of Rising RPMs

Quote:
Originally Posted by KarthikK View Post
vsathyap, I had a similar problem in my Accent 1.6 GLS, but I used to observe it happening more in the mornings than at nights. Don't ask me why . I had similar symptoms to what you mentioned, when my car was at 40k kms age too, and you might be happy to hear this - NO, it didn't turn out to be a clutch overhaul or any such scary expense.

I'm not sure how different your case is, but for me they cleaned the throttle body and this fixed the problem. Advaith Hyundai (Sarakki, JP Nagar) did not charge me for this, and were kind enough to attend to the problem immediately. Please check with your regular service advisor on this possibility.


msaudf, even if the engine was trying to warm up, it shouldn't be rising to the tune of 3500 rpm. That is way too much .
Quote:
Originally Posted by msaudf View Post
I agree Karthink 3500 rpms is way too high for warming up. I think it would create more damage than any good to the engine, i've seen scenarios where the engine keeps revs up to 2000 rpms during initial stages of the warm up.

This is not a warming up rev that I have been seeing - I know that the cold engine keeps the RPMs high initially.. but this happens on a moderately driven "already warm" engine. I also know the feel when the ECU tries to hold the RPMs for us - definitely not that. I mean.. the revs get so loud that a 2 wheeler driver got S*** scared when my vehicle was revving behind him in B2B traffic and he gave me a "pls dont run over me - i didnt do anything " stare and moved to his left

@KarthikK: Yeah, even I visit the same Advaith Hyundai A.S.S. near the mini-forest park area in JP Nagar regularly. I just wanted to be "well prepared" so that I dont fall to any of their scamming traps, specially around the 40K mark.

Also, I did a little researching on Google and other websites/forums and found that the Throttle body jamming up could be the issue. As KarthiKK has already hinted at the Throttle Body in his reply, I have a feeling it may be this same issue.

I also read around "clutch" related treads on this forum and the most common question was whether the clutch was slipping (1st gear and release clutch wit handbrake ON) - and I can confidently say that the car judders and shudders and tries to move forward - so there is no slipping of the clutch. May be it just needs adjusting??

Any other hints/tips on what the issue could be are welcome!
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Old 19th December 2012, 00:00   #59
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Default Re: RPM shoots up when clutch depressed

Same problem plagued my Palio GTX for 1 full year. Finally, I got the O2 sensor changed 2 months back. In my case analyzer showed no error, so I made a conclusion that Palio's ECU cannot catch faulty O2 sensor

Ideal RPM got stable from 1100 to 800 and average improved from 8 to 11 km pl

I spent 5.5K to import NGK O2 sensor from UK. The original one in GTX was of Bosch 0258006193

Last edited by neosmart : 19th December 2012 at 00:04.
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Old 19th December 2012, 01:08   #60
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Default Re: Curious Case of Rising RPMs

Quote:
Originally Posted by vsathyap View Post
Hi All,

I'm facing a really strange problem with our Accent. Here are some details of the vehicle:
Most of the modern car's throttle bodies are electronically actuated(drive by wire). So there is a possibility of sensor fault, like the accelerator pedal sensor but since you said that accelerator is doing the job once gear is engaged properly so probably it is not the cause of the problem.

I think your 'idle air valve' is causing the problem. Its main job is to trim the air going inside the engine to keep the engine speed stable during idle. Mostly its a stepper motor which is opened and closed to control the air entering the engine. May be it is held fully open allowing lot of air to the engine and making it to run at higher rpm.

If your car is having a drive by wire system then most likely you will not be having the 'idle air valve'. In cars with this system, it is the accelerator pedal sensor's job to bring the vehicle back to idle. If you take your foot off the accelerator, the ECU knows that driver demand is zero, then if engine rpm falls below a threshold set point above the base idling rpm, the ECU will start the idling strategy.

You also told repeated pumping of the clutch solves the issue, could you please check if there is any switch near the clutch lever. I have seen a similar switch in Hyundai Verna CRDI(08), but it was used only for starting. The vehicle will crank only if the switch is pressed.

Please don't forget to update us, once the issue is solved.

Last edited by ecenandu : 19th December 2012 at 01:11.
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