Fiat Doblo 1.3

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Re: Fiat Doblo 1.3

Postby Valhalla » Thu May 23, 2013 2:36 pm

Might be worth a check of the return line pressure, either at the HP pump spill line or at the injector spill rail. If the input pressure is a bit high, that might indicate a restriction elsewhere on the returns. I think that arjen mentioned this a few posts ago.

Have you looked inside the EGR valve to positively identify that the valve is 100% there and 100% closing? It might appear that the valve operates correctly on a scantool, but if the seat is contaminated/damaged, then some systems can readapt themselves over time to show a 0% opening, when the valve is not shutting properly.

Sorry for the confusion over the PD diagnostics - I thought that the Doblo was one of those. :oops: I think that you will get a result on this one, as the symptoms are pretty obvious.
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Re: Fiat Doblo 1.3

Postby ProDiag » Thu May 23, 2013 3:10 pm

Hi Kevin,

I would rule out the EGR system by blocking the pipework in whatever way is easiest, this will rule out that aspect (I suspect that it might be your issue here).

You could prove this with the scope if you had a known good MAF waveform (if the EGR is not sealing correctly the value on the MAF would be lower).

As an exercise you could scope MAF before and after blocking the EGR system, overlay and compare.

Hope this helps and let us know the result.

Matt
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Thu May 23, 2013 8:39 pm

Hi guys,

Who said to blank off the EGR valve? :x Took the pipe off and blanked the manifold. Didn't make any odds. EGR is fully closing as we seen the exhaust fumes come out on overrun, then stop as soon as the egr closed off. Just spent the best part of the evening trying to get the egr pipe back on and cant!!! Gave up and came home now.

Matt, I seem to recall seeing the maf alter in live data in the workshop yesterday. Can't remember the exact figures, but it was very noticeable

Will try and get a fuel return pressure done tomorrow, but we have too much work in and customer wants the doblo back.

Why do customers think our jobs are easy?!
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Re: Fiat Doblo 1.3

Postby Neilcur » Thu May 23, 2013 9:25 pm

Hi Kevin,

Have any fault codes returned? Does the MIL light illuminate? Is it temp related?

Thanks Neil
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Thu May 23, 2013 9:36 pm

Hi Neil,

No codes except glow plug. Not other codes have come back!

It is worse when cold, but still there at normal operating temps but not quite as bad.
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Re: Fiat Doblo 1.3

Postby Neilcur » Thu May 23, 2013 9:38 pm

I know the focus tdci's are bad for going into limp mode/lack of turbo boost if there is a glow plug issue so if i was you i would correct that fault and see what happens as the glow plugs are used for the emissions.

Sounds daft i know but can't overlook anything on a modern vehicle.

Thanks Neil
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Re: Fiat Doblo 1.3

Postby KimAndersen » Fri May 24, 2013 12:12 pm

Hi Kevin

I have looked at the first capture you have taken of the MAF sensor and injector number 1 again.

Are this capture taken with a warm engine ?

The reason I´m asking is - that I know that some cars equiped with multijet injection system controls
the number of injections under and above 60 degrees.

If you look at this capture here - I have marked where there switch in the injectors from 2 pilot
injections to 1 pilot and 1 main injection event.

Doblo_Pilot_Injection.jpg


What there could be interesting to know at this point is at how many engine RPM´s this transition happens.

The air mass sensor are showing a reading of 3.99 Khz, but how do this correspond to airflow in gram pr second g/s.

I don´t know if this info is of any help. :wink:

Regards
Kim
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Fri May 24, 2013 12:41 pm

Ok, Doblo all built up ready for customer to collect. They need it back again, so can't do much else with it.

I tested the fuel return pressure and it is sitting at 1bar.

Neil, your correct about the modern cars. Nothing should be overlooked. Customer has been advised about the glow plugs. Hopefully they don't want us to fit them. I've had a bad experience of one breaking :shock:

Kim, I can't recall the engine temp, but suspect it would have been with a warm engine. RPM wise I'd be guesing at about 2.5-3000.

Should we get this car back again, or they get it fixed, I'll update with the info.

Thanks all for taking the time to contribute with advice etc.

Cheers,

Kevin
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Re: Fiat Doblo 1.3

Postby arjen » Fri May 24, 2013 3:05 pm

To bad you can't complete your diagnostics now the costumer needs the car back, would be nice to know what the actual problem is.

The switch from 2 pilot injection to 1 pilot injection is made at 3100 rpm.
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Fri May 24, 2013 7:42 pm

It is annoying not getting to the bottom of things.

Speaking the customer tonight, we advised getting the injectors tested, but they don't think they will due to possible costs of removing them etc. They also mention how they put Redex in the fuel tank. everytime they did this, there is a noticeable difference? My guessing being they are altering the ignition properties of the fuel, and due to a possible poor spray pattern from the injectors, this redex compensates??

I'm probably talking rubbish now! :roll:
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