General Punto unstable revs

Currently reading:
General Punto unstable revs

Stupid Punto

New member
Joined
Jun 5, 2010
Messages
29
Hi folks wonder if anyone has an idea what the problem is with my 2001 1.2 8 valve Punto with around 54k on the clock.
I took it for an mot and the tester couldn't get it to rev at 3000 revs for long enough to do the fast idle test. He reckoned it was probably a split hose, I've had a look and can't see any issues with pipes.
The car has a bit of a very slight misfire at 2000 revs but runs ok. When I take the revs up to the 3k mark it continues to increase, when you reduce the pedal pressure to get back to 3k it drops of dramatically to nearly tickover speed

Cheers
John
 

howardsam95

New member
Joined
Apr 23, 2012
Messages
285
Location
Essex
Could be idv or something to do with the throttle cable. But then again if its misfiring could be a coil pack or HT leads. Process of elemination. Does it tick over OK?

Sam
 
Joined
Mar 20, 2006
Messages
27,743
Location
Liverpool
If the HT leads are more than 4 years old, hurl them(one at a time) in the bin and replace them (one at a time) with new.

This is the most likely cause of the misfire.

If the issue persists, most likely problem is with an air leak.
 

s and b

New member
Joined
Mar 13, 2011
Messages
7,620
if nothing is obvious like what fingers or the others have said then live data via something like fiatecuscan is the next step
to be honest if the revs are dropping out then i would have thought it would be easy to find but only yesterday i heard a back street mechanic tell his customer the reason his revs dropped was because he had a faulty fuel pump,how i laughed but then it wasnt my business so pay cheap and eat skunk is my motto:)
 

benny279

Banned
Joined
Jan 23, 2012
Messages
3,599
Location
under the bonnet....
my revs on my speedo including fuel gauge and temp gauge go up and down, but its all good! its only cause my bass box in the boot is on full whack! it goes with the beat:slayer:
 
OP
OP
S

Stupid Punto

New member
Joined
Jun 5, 2010
Messages
29
Thanks for replies I've changed plug leads and plugs but no change, the misfire is very slight more of a popping out of the exhaust. I'll have a try at connecting onto fiatecuscan
 
Joined
Jun 30, 2008
Messages
3,438
Location
Stockport
if nothing is obvious like what fingers or the others have said then live data via something like fiatecuscan is the next step
to be honest if the revs are dropping out then i would have thought it would be easy to find but only yesterday i heard a back street mechanic tell his customer the reason his revs dropped was because he had a faulty fuel pump,how i laughed but then it wasnt my business so pay cheap and eat skunk is my motto:)
Just slightly hijacking this for a minute, but it is relevant.Wwhat is the lead you need to connect to Fiatecuscan? I bought one off ebay but when I connect it says I need an elm 327obd connector. But I read that some of these are duff anyway. What's the best place to get one?
 

benny279

Banned
Joined
Jan 23, 2012
Messages
3,599
Location
under the bonnet....
Just slightly hijacking this for a minute, but it is relevant.Wwhat is the lead you need to connect to Fiatecuscan? I bought one off ebay but when I connect it says I need an elm 327obd connector. But I read that some of these are duff anyway. What's the best place to get one?

buy the revised vagcom lead that has the switch to switch between modules e.g. abs,airbag,engine etc its not that expensive:)i need to get one at some point myself:cool::cool::cool:
 

benny279

Banned
Joined
Jan 23, 2012
Messages
3,599
Location
under the bonnet....
http://item.mobileweb.ebay.co.uk/viewitem?index=0&sbk=1&nav=SEARCH&itemId=320903147294

wherever reliable I can't say, but if you're after quicker delivery theres this this option....

http://www.scantool-direct.co.uk/multiecuscan-kkl-vag-com-cable-with-pin-switching-121-p.asp

slightly more in price but good company ive brought from them before:)
but if you fancy been a right cheapo you could buy the standard vagcom kkl lead, open it up and make your own switch,a google search will find the guide:D
 

s and b

New member
Joined
Mar 13, 2011
Messages
7,620
buy the revised vagcom lead that has the switch to switch between modules e.g. abs,airbag,engine etc its not that expensive:)i need to get one at some point myself:cool::cool::cool:

ive got one of these but cant get comms on abs so mainly gone back to using the 3 coloured leads and kkl or elm depending
 

s and b

New member
Joined
Mar 13, 2011
Messages
7,620
http://item.mobileweb.ebay.co.uk/viewitem?index=0&sbk=1&nav=SEARCH&itemId=320903147294

wherever reliable I can't say, but if you're after quicker delivery theres this this option....

http://www.scantool-direct.co.uk/multiecuscan-kkl-vag-com-cable-with-pin-switching-121-p.asp

slightly more in price but good company ive brought from them before:)
but if you fancy been a right cheapo you could buy the standard vagcom kkl lead, open it up and make your own switch,a google search will find the guide
:D

if you get it wrong you stand a chance of putting a back emf up your woopsie and breaking something
andy recket can explain better he had a bigger mecanno than me:D;)
 

s and b

New member
Joined
Mar 13, 2011
Messages
7,620
Thanks for replies I've changed plug leads and plugs but no change, the misfire is very slight more of a popping out of the exhaust. I'll have a try at connecting onto fiatecuscan

popping suggests leak
do you have a vacuum gauge to pop on the inlet manifold
 
OP
OP
S

Stupid Punto

New member
Joined
Jun 5, 2010
Messages
29
No i don't have a vacuum gauge what would I need and where do I connect it. Is it a matter of removing one of the existing tubes or fitting a tee piece temporarily. What reading would I look for.
 
OP
OP
S

Stupid Punto

New member
Joined
Jun 5, 2010
Messages
29
I've fitted an instrument cluster with a rev counter while I try and sort this issue out, the clock is flashing to indicate the swap, can I sort this out with the fiatecuscan software package or does it need a different tool
 

benny279

Banned
Joined
Jan 23, 2012
Messages
3,599
Location
under the bonnet....
I've fitted an instrument cluster with a rev counter while I try and sort this issue out, the clock is flashing to indicate the swap, can I sort this out with the fiatecuscan software package or does it need a different tool

you can use fiatecuscan with the correct leads. you will need the elm interface, but you may need full version of fiatecuscan.
 
OP
OP
S

Stupid Punto

New member
Joined
Jun 5, 2010
Messages
29
I have measured the resistance on the throttle sensor it starts out at around 2.7 k ohms as I open the throttle it rises to 3.6 k ohms but as I go to fully open the resistance drops again. Is this correct.
 
Top