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Fiat Punto 1.2 8v 2001 - Poor idle & flat spot #

Posted by John CW kennard on November 12, 2010, 2:46 pm

Year of Manufacture *: 2001
Engine Size and Code *: 1.2 8v

We have a fiat punto in with uneven idle, a tendency to try to stall or die while pulling away and flat spots, especially when cold but also when at running temp, no codes are present, coolant temp sensor is reading correct, lamda sensors are switching, the vehicle has new ecu and coil packs, all gas readings are fine, have carried out a smoke test to check for air leaks with none found, the only issue apparent is when connecting a vacuum gauge the vehicle appears to have poor vacuum.
Any help appreciated

Re: Fiat Punto poor idle & flat spot

Posted by Sean Mc Gettigan <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5291' width='330' height='300' border=0 style='border:none;'> on November 12, 2010, 3:36 pm, in reply to "Fiat Punto poor idle & flat spot "
Sean McGettigan

Valve timing John?

Regards
Sean

Re: Fiat Punto poor idle & flat spot

Posted by John CW kennard <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5582' width='330' height='300' border=0 style='border:none;'> on November 12, 2010, 4:20 pm, in reply to "Re: Fiat Punto poor idle & flat spot "
John Kennard

Sorry, forgot to say, timing has also been checked and is correct

Re: Fiat Punto poor idle & flat spot

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 12, 2010, 6:51 pm, in reply to "Re: Fiat Punto poor idle & flat spot "
Peter Mutlow

Evening John,

These things suffer from faulty TPS and ECU software problems. Normally you will get fault Codes P351 and/or P352 if it is a software problem but this is not always the case. It would be interesting to see what the vacuum figures are. Also surprised the gas readings are ok. Would expect something to show there on HC,s or O2. I would take particular attention to compressions and MAP sensor. Might be worth scoping TPS to see what that is doing.

Regards

Pete M

Re: Fiat Punto poor idle & flat spot

Posted by lee woods <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3096' width='330' height='300' border=0 style='border:none;'> on November 12, 2010, 8:35 pm, in reply to "Fiat Punto poor idle & flat spot "
Lee Woods

The poor vaccum is the key here i think , is top dead mark on outer pulley definatley correct, take number one spark plug out and make sure its correct with a screwdriver on the piston , have seen one of these were cam belt gear has spun over woodruff key , take rocker cover off and see if any cam lobes have worn down , have seen thes with blocked oil feeds to lobes.
Whats the compressions up too ?

What was the vac reading ? good engine bout 21 inches of mercury

Some things to have a go at .

Lee

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