Idle very irratic and jerky acceleration-UPDATE

T

tiggy1985

Member
As the titles says my 2005 2.5se is very jerky on acceleration and I have noticed the idle is very irratic? The rpm needle bounces about quite abit at idle.

The car feels really sluggish under 2-2.5k rpm but after that it pulls fine and feels really quick.

Is this normal?? I seem to think not but could be wrong!

Thanks in advance
 
Potentially a coils pack breaking down. Not saying definite but it is a common issue with these cars.

Do a search, there are loads of threads on this type of issue :-)

Matt
 
Cheers Matt, also when starting up it smells really strong of petrol as if its running rich. Would that coil pack cause this aswell? Probably would as its not buring the fuel correctly?? Am I thinking along the right lines?
 
^^^^^ correct, if one or several coils aren't igniting, the smell of petrol would occur. Pretty sure CJ had a ''how-to'' on replacing them. Pretty straight forward, simple task really...
 
Could be a number of things, if its just hesitant on acceleration and not misfiring then most likely the intake camshaft sensor.

If the sensor is operating out of accepted range the DME will put the intake camshaft into a failsafe position - max advancement. Which would reduce low end torque and would also cause the motor to run rich.

The only way to truley know is to get some diagnostic codes read.
 
Possibly a faulty ignition coil.

Was ingition coil no.5 in mine, when the car wouldn't accelerate properly and struggled to reach a comfortable speed on the motorway on the way to work.
 
thanks eveyone.

I have also been reading a few interesting posts on here about the MAF. From what they were saying on there the MAF could also cause these symptoms?

Does anyone have a "how to guide" or a picture of the position in the engine bay so I can take it out and have a look (I will be careful with it I promise!)

Edit- I have found the position thanks to shipkiller.
 
Just be careful mate with this sensor as it is really fragile and really costs a small fortune.. Also do not be tempted to clean it with a spray or whatever. This may lead to further problems.
 
Cheers for the reply. I have seen a few posts on here about cleaning them and they use a special MAF spray. Would you not do it with that?

Anyone else think this?
 
Your not suppose to spray anything on the MAF but i think people, if they do, use isopropyl alcohol as it evaporates without residue. Available from maplins or other electronic places i would have thought. Try unplugging the MAF and driving the car see if it stopps being as jerky, the DME will resort to predeterined parameters for fueling. EML will come on however.

Could also undo the oil filler cap when car is idling, with it off the revs should drop as unmetered air is entering the system.

Get a cheap OBD II scanner from amazon, circa £23, and see if there are any pending fault codes present.
 
Thanks for everyones input on this.

I have an update!

Bought a can of CNC MAF Cleaner from ebay.

Took out the MAF and pretty much soaked the sensor in it. Left to dry for a hour and everything is sorted :D No surges, idle is spot on and power delivery is perfect. Very happy I just saved myself £240.00 on a new one from the stealers.
 
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