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Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration - Fixed #

Posted by Barry Eger on September 24, 2009, 4:48 pm

Year of Manufacture *: 2002
Engine Code or Type *: 187a1.000
( Optional ) Scanner used: Autodiagnos and Multiscan

Hi every one,

I was called out to this car today, it was unsafe to drive. When pulling away the car surged badly and when revving stationary it it did the same.The mil light would come on momentarily when revving at standstill but not when driving.

There were no fault codes present on fiat or eobd.

The problem is the injectors are shutting down momentarily, like on overrun, this can be seen on my scope clearly. Gas readings at idle are perfect co=0.01 hc=5 co2=15.80 o2=0.15 lambda=1.01 The tps is .6v rising to 4.3v with no glitches. Cam sensor looks fine on my scope. Throttle body cleaned and accelerator cable released. New plugs had been fitted a week before the fault appeared, ht leads and the two coils are working correctly. The ECU on this model is on the near side wing not on the throttle housing. I reset the adaptions with Autodiagnos to no avail.

Has any one come across this before? or maybe give me another prospective on the problem.

I really need a bullet any kind of bullet so I can end it all

Any help will be gratefully accepted.

Barry

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by Tony Ludford <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5539' width='330' height='300' border=0 style='border:none;'> on September 24, 2009, 5:33 pm, in reply to "Fiat Siecento 1100sporting surging on acceleration"
Tony Ludford

"New plugs had been fitted a week before the fault appeared,"

So have you replaced them in case they're incorrect or worse, copies?

Jist a thot!!!

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by Michael Whitworth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5568' width='330' height='300' border=0 style='border:none;'> on September 24, 2009, 10:10 pm, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"
Mike Whitworth - Administrator

>>>>in case they're incorrect or worse, copies?
<<<<

Or worse still, NGKs

Mike

M.O.M. Miserable Old Manc

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by Gwyn Williams <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5354' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 12:41 am, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"
Gwyn Williams

Hiya Barry, Could it be the idle motor? Is it the Bosch type as fitted to the Corsa throttle units? These had idle switches in them that behaved just like this when faulty. Knowing you, i am probably completely wrong! Regards, Gwyn

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by john womack <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2611' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 8:25 am, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"
John Womack

hi barry

whats cranksensor doing????

done a couple fiats very simlar.

regards john

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by Tony Sefton <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5581' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 8:57 am, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"

I Had a Panda Yesterday with a slight stutter on revs and logging "ECU Internal fault" "EEprom Error". and "injector misfires"

We checked coils and spark plugs as a starting point.

No 1 Spark plug was FR8DC+ and no 2, 3 and 4 were F8DC.

It turns out that the problem only started when the customer changed the oil and Spark plugs, He thought it might have a faulty plug, so went back to the spares shop and bought 1 more plug in case one was faulty. ( thats why it had one correct plug fitted )

This Spares shop has been warned on several occasions about this problem and if they are not carefull will end up with a massive claim against them, espescially if the car ends up in one of those places that fits parts just on what the machine tells them, most places would replace the ecu and then insist that the faulty spark plugs had destroyed the ecu and run a bill up for hundreds or thousands of pounds.

I have seen that happen with a peugeot where it had had the wrong spark plugs fitted and the speedo kept dropping off, The Main Dealers fitted a new speedo head and it kept happening, so they fitted another speedo head and eventually found the Incorrect spark plugs, they then insisted that the spark plugs had destroyed the 2 speedo heads and charged for the lot.

. i think that if they had found and changed the spark plugs, the fault would have been cured.

( Easy for any garage to believe the Diagnostic machine ) and would anyone be in the wrong to replace an ecu when the diasgnostic machine says, " ECU INTERNAL FAULT" and EEPROM ERROR". )
?????????

Tony.

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by keith brown <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1429' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 9:22 am, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"
Keith Brown

Barry , is this the version with external map sensor very unreliable! bolted close to ecu, hth,also had one which would not adapt,disconnected the ecu for five mins & hey presto,perfect,italian cars have more attitude than french ones.keith

Re: Fiat Siecento 1100sporting surging on acceleration

Posted by Barry Eger <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5591' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 3:53 pm, in reply to "Re: Fiat Siecento 1100sporting surging on acceleration"

Thanks for all the replies,

Tony & Michael I have had plug problems before on Fiats so I changed plugs and leads today fault still there.

Gwyn It has a idle control valve like the Vaxhalls but it checks out OK and like the TPS is non movable and is pressed into the throttle body.

John The crank and cam sensors are giving good scope waveforms.

Tony What I cant understand is when revving up and forcing the fault the mil light comes on but nothing is stored in the ecu memory. I disconnected a few of the sensors to check ecu for picking up faults and they all showed up.

Keith This model has a map sensor on the manifold next to the throttle body.

The symptoms are exactly like a corsa with a jammed open throttle actuator holding the butterfly open and fooling the ecu into thinking its on over run which switches the fuel injectors momentarily off. My thoughts are "a" tps which is pressed into the throttle body and at .6v may be just over the closed limit "b" the ecu may be at fault.

Barry

Lets do it to them... before they do it to us...

Re: Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration #

Posted by ian slattery <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1196' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 9:03 pm, in reply to "Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration #"
Ian Slattery

With the mil light coming on can you read in eobd and look in pending codes. This may or may not show something.

Re: Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration #

Posted by Barry Eger <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5591' width='330' height='300' border=0 style='border:none;'> on September 25, 2009, 10:12 pm, in reply to "Re: Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration #"

Hi Ian

I refer the honorable gentleman to my first post, no codes in eobd, this also includes pending

After doing some more research, I think the ecu may be causing this problem, I do tend to get tunnel vision on problem's that's why I value this site, the responses always give food for thought.

Barry

Lets do it to them... before they do it to us...

Fixed #

Posted by Barry Eger on September 29, 2009, 4:41 pm, in reply to "Re: Fiat Siecento 1.1 Sporting 2002 - Surging on acceleration #"
Message modified by board administrator September 30, 2009, 12:59 pm

Hi all

A new ecu fixed this beast.

Thanks for your help

Barry

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