Mis fire under 1500rpm?

[mac11irl]

Hey Guys,

 

just wondering if anyone else has had this,

the missus has been driving her citigo for about 6 weeks now,

but yesterday, and today, she told me that when shes taking off, or taking a tight turn

when the revs are low, theres a rattle.

 

I took it out for a spin just now, and found that when the revs drop below about 1500rpm,

ie turning left at a jctn in 2nd gear, or slowly nudging out of a tight parking space,

it does develop a rattle / banging noise.

i thought maybe it was just the engine being under powered for the gear, but ive driven it the same way,

as has the wife, since we got the car, and never had this before.

maybe its just something loose vibrating at low revs? but it goes away above 1500 revs,

and doesnt happen if you give it an extra bit of power when taking off.

thats not really practical on a mini roundabout though.....

[staib]

Isn't that (death) rattle simply telling you the revs are too low? I suspect the engine needs to be in a lower gear, or the clutch slightly slipped to keep the rpm up...

At only 200 miles am still running in my little 'Schkood', and therefore keeping rpms well away from those lower limits.

[mac11irl]

It does seem like the death rattle, but given it never did it before yesterday?

at the same junctions, at the same speeds, in same gears....

like a mini roundabout in 2nd gear, which is perfectly normal.....

and ive done the same manoeuvre the same way, a dozen times with the car already and hasnt ever done this rattly thing before yesterday,...

 

it just seems a little odd, and im not entirely sure if its coming from the engine or gearbox.

 

went to check for a loose coilpack or something just now,

hadnt really taken any notice that the air box is mounted on top of the block, so cant get at them....

Have a feeling i might take it for a spin down to the dealer we got it at during the week,

i know the mechanic down there anyway, so he might shed some light on it.

[philhoward]

The oil in the gearbox is quite thin, so any "revs too low" rattle could well be amplified compared to other cars, but it's a bit subjective - trying to diagnose a rattle via a written medium (this forum)!

 

If you're not happy, make sure you can repeat it and get it to a Skoda garage - arrange for a tech to sit in the car whilst you replicate it otherwise you'll probably end up with the "no fault found" answer.  See if they have a demo car in - see if that does it as well?

[Neo_VR]

Itll be the ****e gearbox..

Mine is the same. it defo doesnt like being laboured in low RPM. believe its known as "gear cluster rattle"

[mac11irl]

So..... today, not doing it as much as it did over the weekend -

i even really tore the ar5e out it - mini roundabout in 5th gear....

normal low rev chugging, and almost no rattles... just a tiny bit compared to over the weekend...

so im now thinking... that its actually a vibrating something or other underneath?

like an exhaust mount come a tidgy bit loose, or moved. or really stupid like a pebble lodged somewhere.

wont get to check until maybe tomorrow evening before work.

as a side not, i noticed something else while testing, though i'll be writing it up in the clutch click thread...

[Stormchaser]

Yeah remember clutch click every trip

Sadly mine doesn't.

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[stooz]

there isnt much need to go above 2000rpm so I dont think its the revs. Having had something similar sounding in other cars, and without hearing the noise, I could suggest drive shaft boots or wheel bearings. or even suspension bushes.

 

They shouldnt be worn yet, but winter salt might have had an effect. a garage should easily be able to check these 3.

[mac11irl]

Im going looking the front end when swmbo gets home from work, i reckon its some heat shielding along the exhaust route now...

or a stone stuck somewhere, as its not as bad as at the weekend...

 

Its not a wheel bearing, i know that noise, nor is it suspension bushes.

[Stormchaser]

Lots of reported incidents on the UP forum about heat shields working loose. Seems quite common.

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[mac11irl]

Im going to give you the win OCD

Have to get under the car this evening, when the wife gets home to confirm,

but im pretty sure i know your right.

Ffrom a quick look theres a heat shield above the exhaust, behind the wishbones,

Just at the start of the floor pan.

reckon its that one resonating at particularly low engine engine vibration