Hestitation between 1500 and 2500 revs

**Marky** · 23rd July 2010, 09:43

I get a hesitation between 1500 and 2500 revs. Its noticable in 2nd, 3rd and 4th gears and it really only happens when I am NOT giving it the beans. I have had it where I am crusing along at 30 or 40 and I lift off for a little then apply the gas again and it hesitates.

I have replaced the EGR valve with a brand new one and it has made no difference. The old one wasn't that dirty and the piston moved freely.

The car is on 94k miles so I am due a new cambelt (and aux belt) in the next few months. Would a worn cambelt have anything to do with this problem?

Anybody got any suggestions? Its a 1.9 120 oil burner.

Thanks

**Grumpy1954** · 23rd July 2010, 10:12

This seems to keep coming back, I took mine back to the dealers a week after collection as I noticed when I lifted off, approaching a roundabout or junction, if it was clear and I put the power back on, it hesistated. They found no fault, and I just put it down to the autobox getting caught out, not sure what gear to be in. Oddly enough, I put normal derv in the last two times instead of V power, and it got worse again.

**Marky** · 23rd July 2010, 15:19

This looks to be a worrying common problem:

Another CDTi "missing" question
Lift off stutter - 1.9cdti 150
Misfire 1.9 cdti 120

Is a hesitation the same as a misfire??? How do you know if its a misfire?

I will have a good look at my turbo hose this weekend as the vac pipe has been changed.

**Marky** · 29th July 2010, 08:39

Well I checked the VAC pipes and one was a bit loose so I pushed it back in firmly.
I took the big pipe off the throttle body to see if it was manky. It looked fairly clean just a bit wet oil (not sludge) around the opening.
I also cleaned the Boost sensor last night (was a bit sludgy).

Anyway the car seems to be a bit smoother and has a bit more pace, you can hear the turbo sucking air more than before. But I still have the hesitation :-(

Can't find where I saw the advice but thanks to the person who suggested loosening the hex bolts on the EGR to get at the boost sensor. I managed to get a torx bit attached to a mole grip in the small gap to undo the boost sensor, without removing the EGR completely.

**winnie2457** · 29th July 2010, 09:05

the oily film on your throttle body is from your oil breather system just after the air box the oil is sucked through the seperator which is not good and then deposited through your turbo and intake pipes then manifold and the sludge on your boost sensor is a combination of oil from the breather and soot from your egr this can cause hesitation and missfire since i have had a new manifold blanked egr valve cleaned the whole intake system inc throttle body and boost sensor etc etc i then let my oil system vent to atmosphere and now i have a squeaky clean inlet system and no hesitation or misfire at all this cured my problem

hope i canm help other ppl too

**Marky** · 29th July 2010, 09:30

the oily film on your throttle body is from your oil breather system just after the air box the oil is sucked through the seperator which is not good

Every car I have ever had has this type of system. It has never sounded right to me that they put an airfilter in to "clean" the air then dirty the clean air with oil. The wife had a VW Golf MK3 and the airbox was constantly filled with oily mess. I ended up disconecting the oil breather pipe from the air system and there was no difference apart from a clean air system.

since i have had a new manifold blanked egr valve

So you have blanked the egr on the manifold side only? Did you use the fiat kit or made your own?

i then let my oil system vent to atmosphere

How did you do this?

Thanks, Mark

**JohnFol** · 29th July 2010, 11:16

I have exactly the same. It happens when cold and when hot, no warning lights, and not consistent. Like you I'm on around the 100k mark but unlike you I've had the cam belt changed.
Interestingly I chucked some Millers in this morning and straight away it has behaved well. I don't believe there has been any magical instant cleaning of the injectors, but wonder if the increased cetane has tricked a sensor or compensated for an inaccurate reading . .

Really keen to get this one fixed . . .

**Marky** · 29th July 2010, 13:52

I've have used Redex Diesel additive recently but it has made no difference.

In very rare circumstances the car will kangaroo slightly at about 1800 revs, but thats rare and its usually a quick hesitation.

Its really annoying. Especially since I have now decided that I want it fixed.

**Damo77** · 11th September 2010, 17:02

Any update on this Marky???????

I too have this misfire and have also replaced my EGR but hasn't made any difference. The old EGR was a real mess (44,000 miles)

As you say "This looks to be a worrying common problem!" but after constant searching I've still not been able to find a solution.

Did you have any success???

Damo

**lesj** · 11th September 2010, 23:36

After much consideration I'm beginning to think this fault (which I also have) could be caused by a sticky injector pintle.
Reason I think this is the car is fine during hard acceleration but hesitates under light throttle.

The Millers may be effective as it is a much more aggressive cleaner than Reddex.
I've just chucked in some BG244 and will give it a week or so before deciding.
Next plan will be to open the fuel filter resevoir and dump in some neat injector cleaner if this does not work.