Technical Jerkiness at lower speeds

[Gman88667733]

I had forgotten about this issue since I hadn't driven the Panda much for a while, but now I drive it every day, I notice it again.

When you drive slowly, like 1st or 2nd gear, if you come off the gas at all the car bucks and jerks quite violently. I'd understand in 1st gear if at high RPMs, but even in 2nd pootling along it does it. Different to how it would react if the car was labouring at low RPM.

I'm not quite sure where to start with this one, I haven't seen much about it online.

It does it whether hot or cold. It is an 04 1.1 Active.

(I'll check later on my way home at what speed this stops and update.)

Thanks

 

[portland_bill]

There have been a few posts about this over the years. It seems it is a 'characteristic'. The 'throttle off' control of fuelling is poor, cutting it abruptly, making very slow work uncomfortable. Been living with mine for 11 years now.

Some cars seem to be worse than others, but really there does not seem to be a fix.

At slow speeds, I tend to use the clutch, drop it just before/as the power comes off to alleviate the jerk. Unless you need to wake up your passenger, of course.

 

[koalar]

A 1.1 04 active shouldn’t drive like this

I had I 1.1 06 active with cable throttle. Drove fine at low revs. In first and second it should accelerate from 750 rpm nice and smooth and poodle at 30 mph in fith. In fact it’s better than the latter 1.2 eco in my opinion.

 

[koalar]

Dose yours have cable throttle body ?
Do you have any way to read the fuel trims ?
Have you looked at the spark plugs ?

 

[timmycm850]

I thinknour 1.2 used to do this a bit. I tend to take up the slack in the accelerator cable on ours(slide in cable sleeve gripper just under the air filter casing on the rhs).

I also occasionally put high octane E5 fuel in it and this makes it smoother.

TIM

 

[TagSouth]

My 1.2 dynamic has a tendency to kangaroo up the road at low speeds in low gear. I think it's the rather abrupt fuel shut-off when the throttle pedal is fully up and the car's in gear.

Like portland_bill, I find the simplest solution is to hit the clutch for a moment. That forces the car to return to idling, with some fuel going into the engine.

 

[koalar]

My 1.2 dynamic has a tendency to kangaroo up the road at low speeds in low gear. I think it's the rather abrupt fuel shut-off when the throttle pedal is fully up and the car's in gear.

Like portland_bill, I find the simplest solution is to hit the clutch for a moment. That forces the car to return to idling, with some fuel going into the engine.

they kangaroo because there something not quite right.


I have had a 1.2 dynamic 05 flyby wire
1.1 active 06 cable

both drive fine at any speed no kangarooing or sudden shut off.


I now have a 1.2 eco 2010 which does


I have had it on the scanner and the fuel trims go plus at idle and the O2 sensors show rich running.


no idea why its adding fuel when its sensing rich running also


not had chance to look at it as its not at my address.



most poor running is oil settling on the MAP sensor. If it clears up temporarily After a blast of higher revs this is where I would start.

 

[koalar]

you can't as far as I know check the fuel trims in multiecuscan. I can not find an option. I have tried quite hard.

its there in both delphi and WOW

 

[Gman88667733]

I did think it may be a characteristic unfortunately...
I have no way to check fuel trims.
I put new spark plugs in a year ago, but used Bosch ones instead of NGK (my usual go-to)

 

[koalar]

I did think it may be a characteristic unfortunately...
I have no way to check fuel trims.
I put new spark plugs in a year ago, but used Bosch ones instead of NGK (my usual go-to)

take the airbox off and post a photo looking straight down the throttle body
Only two 10 mm bolts. You will need to carefully pull off the small plastic pipe

 

[Gman88667733]

take the airbox off and post a photo looking straight down the throttle body
Only two 10 mm bolts. You will need to carefully pull off the small plastic pipe

I had the throttle body off and cleaned both sides a few months ago. It wasn't too bad to begin with to be fair.

 

[koalar]

I had the throttle body off and cleaned both sides a few months ago. It wasn't too bad to begin with to be fair.

I asked for some photos of the spark plugs

this would tell us if its

running rich
running lean
burning oil
spraying water
and so on


we can't tell anything from they have already been changed

same with the throttle body

from it we could tell

water
soot
oil
flyby wire
icv


why was the throttle body off 2 months ago ?

you have no way to read live data and without any conformation we might as well just sit on a computer and guess every part on the engine. Eventually we will find the culprit. Although it can be expensive doing it this way. as it is we are no further forwards, With nothing to go on.



on my cars these engines 100% do not kangaroo if everything is 100%. There may be difference's in ECU software but I doubt it would be your fault


you dont need to work around the fault by slipping the clutch. The only way you can make them fail is wide open throttle, foot off the accelerator, wide open throttle again without waiting for any revs to rise.


Like I said I have one the movement that not 100%. I have read the live data and I can see the fuelling isn't right at low rpm.

finding drivability issues can be a right pain as the car is almost working. And just about ever sensor, cam timing, compression, spark or fuelling can cause the same symptoms.

 

[portland_bill]

I asked for some photos of the spark plugs

Not in this thread you didn't.

 

[koalar]

Not in this thread you didn't.

correct


I asked have you looked at the spark plugs

"they have already been changed"

doesn't tell us much about how the engine is running, just its unlikely to be spark plugs assuming the correct temperature.

A description or photo would be more helpful

 

[rmjbn1]

When you drive slowly, like 1st or 2nd gear, if you come off the gas at all the car bucks and jerks quite violently.

I'm glad it's not just mine that does that! Again, at very low speeds only, I think only in first gear & I've been working around it by dipping the clutch. Thanks for bringing it up, Gman

I've been helping my other half learn to drive and keep insisting on correct use of the clutch. I get some very old fashioned looks when I'm driving and start kangarooing about in car parks

 

[rmjbn1]

Does anyone have any tips for getting the IACV out of the throttle body, please?

I've tried prising it out with the aid of a Jubilee clip and waggling it with mole grips but it just won't budge and I don't want to destroy the casing.

Struggled to start from hot yesterday, ran rough momentarily a couple of times, the check engine light came on and thankfully off again.

I've cleaned up the plugs, MAP, TB, and around the IACV as best I could, but no luck in removing the IACV for a thorough clean. It's a cable throttle 1.2 by the way.

 

[koalar]

Does anyone have any tips for getting the IACV out of the throttle body, please?

I've tried prising it out with the aid of a Jubilee clip and waggling it with mole grips but it just won't budge and I don't want to destroy the casing.

Struggled to start from hot yesterday, ran rough momentarily a couple of times, the check engine light came on and thankfully off again.

I've cleaned up the plugs, MAP, TB, and around the IACV as best I could, but no luck in removing the IACV for a thorough clean. It's a cable throttle 1.2 by the way.

try disconnecting the upstream O2 sensor. It will throw up an engine check light. Probably idle worse. As it can't adjust the fuelling correctly on the fly it will fall back on some standard predetermined values. I would like to know if this is better, same or worse for kangarooing.

 

[koalar]

Does anyone have any tips for getting the IACV out of the throttle body, please?

I've tried prising it out with the aid of a Jubilee clip and waggling it with mole grips but it just won't budge and I don't want to destroy the casing.

Struggled to start from hot yesterday, ran rough momentarily a couple of times, the check engine light came on and thankfully off again.

I've cleaned up the plugs, MAP, TB, and around the IACV as best I could, but no luck in removing the IACV for a thorough clean. It's a cable throttle 1.2 by the way.

Reading the error code would be a Good clue

 

[rmjbn1]

Thanks for the replies koalar.

Got considerably worse today during a long-ish run (60 mile round trip) Conked out a few times and engine check light now on permanently.

From cold, turned over for ages without trying to fire.

Unplugged & reconnected the MAP, fired up straight away, ran fine for 30 miles on fast roads, but then repeatedly died in town on deceleration or off throttle.

No rough running, either running fine or engine shuts off completely.

Still had full electrics, seems like an intermittent fault killing the spark. On a few occasions the engine kicked back in before coasting to a halt. On others it took a while turning the engine before it would run again. Reconnecting the MAP seems to help, but not every time so maybe not related.

I'm wondering if I've damaged the throttle position sensor whilst cleaning out the throttle body previously?

I cleaned up the TB a couple of years ago by spraying brake cleaner at it, which I know koalar has said NOT to do https://www.fiatforum.com/panda/477...ean-fiat-panda-1-2-a.html?477860=#post4599274

I was more careful cleaning it yesterday with brake cleaner on a cloth, but maybe the damage was done? I'll check resistance on the TPS with a multimeter.

I don't have an OBD cable to run MES yet, will try and get codes read / video of symptoms, I'll also try with the upstream O2 sensor disconnected.

 

[portland_bill]

Did the poor starting and stalling occur after the cleaning operation, or was the cleaning an attempt to address this issue?
If the issue occurred before, were the symptoms the same, or are they now different or similar?