[kenalex]

I have a 2009 Hyundai i30 1.6l petrol, automatic transmission. The car is 10 years old with 53K miles on it.
The car is routinely maintained, regular oil changes and fluid levels checked and topped up when necessary.

I have been having problems with car stalling when idle when in traffic and sometimes when coasting with rpm around 1000 RPM .

There are times when the car has problems starting, where I have to turn the ignition on for a couple of seconds   before starting the ignition of the car to get the car to start.
I did a test to see if I can reproduce the problem by starting the car and have it idle for about 10 minutes to see if it would stall, which it did not. The stalling issue seems to happen after the car has been moving for some time.

There are also times when the car eventually starts it is sputtering, feels as if the car is missing and wants to stall , with the Tachometer showing 0 rpm even though the engine is on. When accelerator is pressed, tachometer needle does not move. When this happens I shutdown the engine wait about 10 seconds and start it would start and not stutter as it did previously, and the tachometer would now register the RPM

I spoke to my mechanic and he mention the fuel filter needs to be changed, as it was not changed since the car was purchased. The fuel filter was changed but the problem still exists.
The mechanic later cleaned the throttle body and the issue remains.

In addition the spark plugs and  air filter were changed as well.

I was thinking it could be the fuel pump could be the issue.

What could be the cause of this issue?

Any help would be greatly appreciated.
Thank you
 

 
 

[Dazzler]

Hi there, I'm no mechanic but I'm having a think about the possible cause or a fix. Hopefully one of our better tech heads will be a long shortly. Unfortunately one of them has gone AWOL 😢

[kenalex]

Thanks for your reply. I appreciate your help 

[Dazzler]

Thanks for your reply. I appreciate your help 

Not a lot of help so far sorry. I'm kind of thinking something electronic is out of whack.  Faulty fuel pump wouldn't cause the Tacho not to show revs when the engine is actually running. With electronic issues a quick fix can be to reset the body control module (BCM) by disconnecting the negative terminal of the battery for a minimum of 30 minutes. That may help. At least it may prompt others to voice an opinion.. even if it's to tell me I'm full of $hit. 

[kenalex]

I did some research and found that all the problems I am experience could be  as a result of a fault crankshaft position sensor. I am still looking to see if I  get more information.

[Dazzler]

I did some research and found that all the problems I am experience could be  as a result of a fault crankshaft position sensor. I am still looking to see if I  get more information.

Use our search function above to search for "crankshaft position sensor"  in parentheses and there are 14 results. I haven't actually read all the threads but surely some will point you in the right direction whether that is the possible cause.

[mickd]

Hi,
Your mechanic has NO IDEA,  how the Hell can a fuel filter make a tacho not work .    Also, same for cleaning a throttle body. FFS.
Ring around and ask a couple of other mechs,  hope plugs & filter weren't changed trying to fix this fault.
 If it is a CPS, do you really want this one delving into uncharted  waters with your car ??

[kenalex]

Thanks for your reply. I will see what I can do

[kenalex]

I asked another mechanic to check out my vehicle  based on the issues I mentioned, He stated it could be a bad ground or crankshaft sensor. He stated it mostly like to be the crankshaft sensor since I reported the 0 RPM issue . He performed  the various test on the various grounds in the engine bay and they were good.  Since the ground was good he will perform some tests against the crankshaft sensor and see how it behaves .

[Dazzler]

I asked another mechanic to check out my vehicle  based on the issues I mentioned, He stated it could be a bad ground or crankshaft sensor. He stated it mostly like to be the crankshaft sensor since I reported the 0 RPM issue . He performed  the various test on the various grounds in the engine bay and they were good.  Since the ground was good he will perform some tests against the crankshaft sensor and see how it behaves .

Thanks for keeping us in the loop. A mechanic on site is always going to have a better chance of diagnosing the problem than us by remote control over the internet. 

[kenalex]

Hi ,
  My mechanic changed the  crankshaft position sensor and car is running  fine now. I have no issues starting up the car. No long cranks to get it start, soon as key is turn car starts. Also my car has yet to stall when at idle or low speed.

I even got a demonstration  on how it crankshaft position sensor works. he unplugged the electrical connector and witness the car stalled.
What I found interesting is that car was able to start the car with the crankshaft positions sensor unplugged but the tachometer was reading 0 and it too long to start and the car was idling very rough. This is what is what I experienced .
He suggested the camshaft position sensor was providing ECU with data to enable it to do the ignition timing which is not ideal.

In addition my car didn't show a check engine light when it was running with the crankshaft sensor unplugged. is it normal the check engine light  to not shown when the sensor is not available ?

Thank you guys for you assistance.

[mickd]

@kenalex
Great to hear, relatively cheap and you now have a new informed mechanic.   

[Dazzler]

Thanks for getting back to us. That is excellent news. 

[coast11]

Hi there! I’m experiencing the same issues, however, after changing the crank shaft sensor it didn’t fix the issue. I’ve gone down the road of getting my ecu cloned as my mechanic thought it could be that.

You made mention of cam shaft sensor, is that different from crank? 

Thanks so much

[Lorian]

what exactly are your issues? maybe start a new thread