Fiat 1.6 2001 primary.

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Fiat 1.6 2001 primary.

Postby hbr » Tue Apr 24, 2012 5:45 pm

Hello i got a problem with a Fiat bravo 1.6. This car won't run good, the map reading is 500 mbar and i can't find any leaks in the intake system with a smoke machine. Also the primary signal i captured is strange, can somebody tell me what is causing this.
Ontsteking Fiat.JPG

Also attached the psdata.
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Fiat primary.psdata
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Re: Fiat 1.6 2001 primary.

Postby Robski » Tue Apr 24, 2012 6:07 pm

Have you checked the timing ? ( verify MAP with a vac gauge )

The primary looks like a misfire.
Last edited by Robski on Tue Apr 24, 2012 9:01 pm, edited 1 time in total.
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Re: Fiat 1.6 2001 primary.

Postby GRUSS » Tue Apr 24, 2012 7:21 pm

Do you have access to fuel trim data? If so, what are you getting for STFT and LTFT @ idle then at 3000 rpm?
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Re: Fiat 1.6 2001 primary.

Postby Kev » Tue Apr 24, 2012 8:49 pm

hbr wrote:Hello i got a problem with a Fiat bravo 1.6. This car won't run good, the map reading is 500 mbar and i can't find any leaks in the intake system with a smoke machine. Also the primary signal i captured is strange, can somebody tell me what is causing this.
Ontsteking Fiat.JPG

Also attached the psdata.


Hi hbr, first I would check the valve timing (costs nothing), then I would be looking for another set of HT leads. If the waveform persists then I would replace the ignition coil in that order. Could you add a bit more information as to the characteristics of the fault as far as running goes!
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Re: Fiat 1.6 2001 primary.

Postby hbr » Tue Apr 24, 2012 9:05 pm

Hello thanks for helping me. I have checked the timing already. This system is not with eobd plug but with an old 3 pin connector, so i can't read the fuel trim, i can see that the mixture is very lean. The car is running like it misfires and when it's hot it stops running when you rev the engine and let it idle again. I also have replaced two bad injectors already, they where shorted. Map is verified with vac meter.
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Re: Fiat 1.6 2001 primary.

Postby Robski » Tue Apr 24, 2012 9:12 pm

Whats the injector PWM ?

Fuel pressure ?

IAC valve ?

How are you seeing the mixture lean ?
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Re: Fiat 1.6 2001 primary.

Postby GRUSS » Tue Apr 24, 2012 10:22 pm

I could be wrong here but looking at the waveform the spark line looks high? Could this be a no fuel misfire?
Have you had the car on a gas analyser and checked the co and HC?
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Re: Fiat 1.6 2001 primary.

Postby Robski » Tue Apr 24, 2012 10:49 pm

GRUSS wrote:I could be wrong here but looking at the waveform the spark line looks high? Could this be a no fuel misfire?
Have you had the car on a gas analyser and checked the co and HC?


Not to me it doesn't.

I would have liked to have seen a snap throttle, that would have shown lean cylinders (lean misfire).

There seems to be more turbulence on channel C in places.


hbr

Can you see the O2 sensor in live data ? take it for a WOT & observe what it does.
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Re: Fiat 1.6 2001 primary.

Postby hbr » Wed Apr 25, 2012 5:41 pm

Hello, fuel pressure is on my to do list, but it has no schrader connection so I have to make some thing to measure it.
I don't have access to a four gas analyser so I can't give you that information. In the life data I can see that the o2 reading is low and it gives a fault code lean mixture. What do you mean by injector pwm Robski? The time that the injector is activated? I can do some more measurements on the injector and a snap throttle test with primary.
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Re: Fiat 1.6 2001 primary.

Postby Robski » Wed Apr 25, 2012 6:31 pm

Hi mate

Yes injector PWM = Pulse Width Modulation ( injector on time ).

If the O2 is low when at WOT ( Wide Open Throttle ) on road test then i would suspect the fuel pressure, for speed rather than making a rig to check pressure you could grab a fuel pump current/voltage capture you may well see what you are looking for on that 1 screen.
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