Author Topic: Random sudden Jolt  (Read 361 times)

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Random sudden Jolt
« December 04, 2017, 00:37:32 »
Hi everyone I have bought myself an i30 1.6L diesel auto and love it, but I have a slight problem. It will do it cold or hot and any speed braking or not, it's just complety random.

I will just be driving along then all of a sudden it will jolt (like someones tapped on the brakes hard for less than a second) it has 230 tho kms on the clock when it happens; the revs drop off and come back up. I have replaced the engine as the old one has bad timing rattle then i accidentally cooked it but i used the injector and pump that came on the new one. Got it all coded done diesel filter air ect; it did it on the old engine and also now the new one.

Anyone have any ideas where to look or what it could be? thanks


  • Hyundai i30 1.6 Diesel

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Re: Random sudden Jolt
« Reply #1 : December 04, 2017, 00:53:45 »
Welcome DD,

Jeepers, that's an odd one, especially as you can discount the engine. Sounds like you don't muck around when you have a problem.  :eek:

Sounds like something in the transmission is slipping or jamming maybe, but I'm no mechanic, so see what others say.  :undecided:
  • MY18 PD SR & 2014 1.6 GDi Tourer (Prev had 2008  i30 CRDi & MY11 Petrol CW)

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Re: Random sudden Jolt
« Reply #2 : December 04, 2017, 00:59:55 »
Could it be the ABS playing up :undecided:

Re: Random sudden Jolt
« Reply #3 : December 04, 2017, 01:21:21 »
I thought about abs so ive allready pulled the fuses to abs to eliminate that :lol:
  • Hyundai i30 1.6 Diesel

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Re: Random sudden Jolt
« Reply #4 : December 04, 2017, 01:27:45 »
I thought about abs so ive allready pulled the fuses to abs to eliminate that :lol:

Better put them back, you will be a dead duck if you need the ABS!  :winker: :snigger:
  • MY18 PD SR & 2014 1.6 GDi Tourer (Prev had 2008  i30 CRDi & MY11 Petrol CW)

Re: Random sudden Jolt
« Reply #5 : December 04, 2017, 01:43:19 »
I thought about abs so ive allready pulled the fuses to abs to eliminate that :lol:

Better put them back, you will be a dead duck if you need the ABS!  :winker: :snigger:

Yes i only done that till it done it again then i put them all back in  :lol: :goodjob2:
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Re: Random sudden Jolt
« Reply #6 : December 04, 2017, 02:10:24 »
Could be in the trans being auto. they are know to have valve body issues. Could it be the torque converter  lockup?

Last time the trans was flushed out and new fluid?
  • 2008 i30 SLX CRDi Auto, 2010 i30CW SLX CRDi Auto

Re: Random sudden Jolt
« Reply #7 : December 04, 2017, 02:54:54 »
Could be in the trans being auto. they are know to have valve body issues. Could it be the torque converter  lockup?

Last time the trans was flushed out and new fluid?
Im not too sure but the trans oil looks good and nice and red no  burnt smell the valve body looks like it has been replaced as the sump has come off before and it having 230tho kms on the clock i hope its an easy cheap fix and not a replacement gearbox
  • Hyundai i30 1.6 Diesel

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Re: Random sudden Jolt
« Reply #8 : December 04, 2017, 14:37:21 »

How many kms on  replacment engine?
Injectors?correction codes? Ecu new old..
If you can drive it and record live data on obd you will be very close to answer yourself on
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Re: Random sudden Jolt
« Reply #9 : December 05, 2017, 01:25:51 »
73 tho km's on new engine but all of a sudden today the gearbox is playing up its fine in reverse but as soon as I go into a forward gear it just fells like it's slipping like no drive I can't make it up a light incline it just revs up and moves slow it started working fine again then I have hopped back in it now and it's doing it again the fluid looks really clear kind of red/pink I hope I don't have to do the trans as well.
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Re: Random sudden Jolt
« Reply #10 : December 05, 2017, 02:15:04 »
73 tho km's on new engine but all of a sudden today the gearbox is playing up its fine in reverse but as soon as I go into a forward gear it just fells like it's slipping like no drive I can't make it up a light incline it just revs up and moves slow it started working fine again then I have hopped back in it now and it's doing it again the fluid looks really clear kind of red/pink I hope I don't have to do the trans as well.

Like I said , sounded like trans and sounds like Valve Body now. Possibly is failsafe 3 rd gear. Try selecting manual 2nd, if the electronic control has quite the shifts will be quite nasty.

If you have a scanner I'd expect some codes to be present. Could be other things like shaft speed sensors too.

I had sensor failure in mine and got by doing 300-400k on along trip with just 2nd and third manual shifting , not fun and not ideal.  Valve body alone if you got it from Korea yourself is about $1000 AUD deliverd here.
  • 2008 i30 SLX CRDi Auto, 2010 i30CW SLX CRDi Auto

Re: Random sudden Jolt
« Reply #11 : December 05, 2017, 03:58:11 »
Hi works again now no codes present and when it was doing it it didn't change to first or second manually still smooth gear changes thanks
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Re: Random sudden Jolt
« Reply #12 : December 05, 2017, 04:41:15 »
Hi works again now no codes present and when it was doing it it didn't change to first or second manually still smooth gear changes thanks

Doubt this is the end of the story. Could also be broken connections(solders) on the flat ribbon that drives the solenoids in the Valve body(internal)
  • 2008 i30 SLX CRDi Auto, 2010 i30CW SLX CRDi Auto

Re: Random sudden Jolt
« Reply #13 : December 05, 2017, 13:17:00 »
It done it again this morning it was fine I stopped came back 3 min after went to drive off and it was stuck in 3rd gear but I was actually driving it this time and I noticed the speedo was jumping around to all different speeds then it came right and it stared changing properly I have a Bluetooth scan tool no code comes up I'm not sure if it can read the trans but could it be the speed sensor where is that located on theses gearboxes? Thanks 
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Re: Random sudden Jolt
« Reply #14 : December 05, 2017, 15:23:47 »
It done it again this morning it was fine I stopped came back 3 min after went to drive off and it was stuck in 3rd gear but I was actually driving it this time and I noticed the speedo was jumping around to all different speeds then it came right and it stared changing properly I have a Bluetooth scan tool no code comes up I'm not sure if it can read the trans but could it be the speed sensor where is that located on theses gearboxes? Thanks

Was the scan tool attached when it went crazy? I had issues with my BT scantool on my car which caused havoc.
  • 2008 i30 SLX CRDi Auto, 2010 i30CW SLX CRDi Auto

Re: Random sudden Jolt
« Reply #15 : December 05, 2017, 16:15:31 »
It done it again this morning it was fine I stopped came back 3 min after went to drive off and it was stuck in 3rd gear but I was actually driving it this time and I noticed the speedo was jumping around to all different speeds then it came right and it stared changing properly I have a Bluetooth scan tool no code comes up I'm not sure if it can read the trans but could it be the speed sensor where is that located on theses gearboxes? Thanks

Was the scan tool attached when it went crazy? I had issues with my BT scantool on my car which caused havoc.
Yea it was it hasn't done it before with it in but I will pull it out and try thanks
  • Hyundai i30 1.6 Diesel

Re: Random sudden Jolt
« Reply #16 : December 06, 2017, 00:53:39 »
I've pulled out the scan tool and all problems I was having disappeared no jolt or anything drove round for quite a while today then all of a sudden it lost 4th and 3rd took a while to get into I'd have to let off then let it get into gear then I can put the gas back on it would red up then change really weird but then I let it cool down and it's fine again would an external trans cooler help this get it out of the radiator
Thanks
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Re: Random sudden Jolt
« Reply #17 : December 06, 2017, 01:21:16 »
I've pulled out the scan tool and all problems I was having disappeared no jolt or anything drove round for quite a while today then all of a sudden it lost 4th and 3rd took a while to get into I'd have to let off then let it get into gear then I can put the gas back on it would red up then change really weird but then I let it cool down and it's fine again would an external trans cooler help this get it out of the radiator
Thanks

Hi ,
Been following your thread.
Leave it as it is,  don't add external cooler. 
The root cause of  your problem has still not been identified.
 Do it when fixed if you wish,  but not really necessary.
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