Hesitation or 'hiccup' when accelerating

[MinniTheMoocha]

I have just noticed that my NS DiD auto has a slight problem when accelerating as it changes gear or is about to change there is a stutter either from the motor or gearbox. I haven't narrowed it exactly which one is at fault. This is when it is being pushed >3000RPM

From rolling you put the boot in (as if overtaking etc) and its pulling like a train then you are rocked forward from deceleration and then it picks up again. Its only momentary! I checked with the other half and she finally says 'oh this has happened to me before I thought it was going to stall', just great now she tells me! after just having it serviced http://140.99.20.180/forum/images/smilies/frown.gif
. I suspect I have been mothering the car up till now running it in etc and never really pushed it hard before. My wife just drives it like our old car (Subaru Forester GT - Turbo 2.0L - a little rocket ship) so has obviously put the boot in much more than me.

What makes it worse is today I tried emulating the problem and was able to get the problem replicated earlier in the day and then could not.

Any ideas? Anyone else had anything similar?

By the way I have had the ECU update done but as mentioned this has happened to my wife which was before this update.

Thanks

John

[SteveG]

This may not be related, but by Pajero experience similar symptoms, occasional loss of power, and nearly stalling at idle, however, these events did not occur often enough to cause too much concern. I put it down to poor fuel quality. During the same period the fuel consumption was a nice 9l/100km (diesel auto) on a long trip.

More recently, the Pajero suddenly lost power, and the engine warning light came on. The light was reset by the dealer mechanic, but the loss of power issue persisted. The MM mechanics found that the turbo boost pressure was wrong (sorry, not sure whether too high or low), but they could not track down the problem and after one week (of messing around) decided to replace the turbo. It made no difference. They traced through the checklist again, and eventually found a partially blocked MAC (? not sure about this until I receive the written report) sensor pipe.

12 long days later, I have the Pajero back. It now appears ok. I imagine that the problem could have been easily fixed had it been correctly diagnosed.

I suggest that you have your service dealer look at the issue, it may be a blocked sensor.

I have to agree with the other threads, following the 15,000km service, the diesel engine is much quieter. The MM dealer desk jocky claimed it was due to the adjustment of tappets, and did not know anything about an ECM update.

[MinniTheMoocha]

Hi Steve,

Thanks for your thoughts. I will get the dealer to check if there are any errors etc. Hopefully I will be able to get the Paj to repeat the fault.

Fuel is an interesting element. This could be the likely culprit, I just wish there was an easy way to know.

[matthewfnorbert]

unlikely to be fuel if you buy from a big brand station.

may have been traction control?

drain fuel filter/check for water

[MinniTheMoocha]

I get fuel from Caltex, usually a Safeway though as they are now everywhere.

No traction control warning light or alarms.

I will check the fuel filter to see if there is any accumulation of water. Good thinking... I will check

thanks

[MinniTheMoocha]

Checked the fuel filter for water undoing the valve and pressing the pump - only diesel came out.

I just remembered if you have water in the filter it should register on the console warning lights....no water = no warning light.

The wife is taking it for a spin today (a good 1 hour run) so will see if the problem occurs again. If so will be in to see the service centre.

[Wilmo]

Mine exhibited the same problem that yours did, with that slight 'hiccup' but only when changing with some high revs on board and hardish throttle application - and even then it was intermittent.

Since the ECU flash it seems to have been resolved as I've not noticed it lately.

[Tigernero]

Ours did the same as well. If pushed hard it will hicup as well. Seems to do it more when we were going up a hill from a standstill.

[MinniTheMoocha]

Well I am glad I am not the only one.

I have had the ECU update and it still occurs???

Still haven't been able to narrow it down so if there are any suggestions or if this is a known problem with a fix please let us know.

Thanks

[matthewfnorbert]

is it a transmission issue? may be a flash for the tranny?

[MinniTheMoocha]

is it a transmission issue? may be a flash for the tranny?

I don't think it is but I won't exclude it.

I did 150kms today and tried when possible to put the boot in and it seemed ok. Its just that there was an occasion when it hesitated but I wasn't able to keep testing as I was on a single lane highway most of the way and the traffic didn't really allow me to be testing it this way!

[WALLYBURGER]

Mine does it as well,but only when the Dpf light is on.My dealer said it stemmed back to the DPF being blocked or partially blocked.The hesitation seems goes away when the exhaust is free.

[MinniTheMoocha]

Mine does it as well,but only when the Dpf light is on.My dealer said it stemmed back to the DPF being blocked or partially blocked.The hesitation seems goes away when the exhaust is free.

That's interesting. After doing quite a number of km's and giving it some stick I have not had it at all today. You might be onto something here....

So it just might be the DPF. I will talk to the dealership next service which is not too far away.

[danc12]

It might be the aircon

Thanks Minni, i thought I had read your post earlier and couldn't find it this time around.

I did something similar ie put the boot in a couple of times and I didn't notice it again, however I got a similar behaviour with air con coming on at close to idle and just starting to accelerate, the engine did the same thing, almost like the load form the air con knocks the wind out of the engine.

I am due for the 1500 check up this friday and have told them about it they are going to check for codes. Will post any results.

Thanks

[zacc]

i know of a mm dealer and his ns diesel backfires, the mechanics are looking into it and they say it is a known issue