Fiat Doblo 1.3

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Re: Fiat Doblo 1.3

Postby Dundeeguy » Wed May 22, 2013 3:56 pm

Ok, have had a little look at this car again.

There is no O2 sensor to be found anywhere.

Roadtested looking at live data. Full throttle from 1,000 - 3,000 rpm boost pressure starts at 1200m/bar and gets to 2350. MAF sensor goes from 300-700. EGR just seemd to sit at 2%. Didn't move at all?? In the workshop the egr would go to 50% if you brought the revs up.

It was noticed the more we did this test, then it would smoke more (white smoke) Also it would misfire on lighter throttle. Full throttle from 1,000rpm causes a little diesel knock untill about 1750rpm.

We have powered up the egr valve and can hear it open and close nicely. So asume it must be working and closing fine. Have watched the readings on the scope in workshop and see the duty cycle alter as the ECU powers it on. So appears that is fine.

We're thinking injector fault, but at the cost of injectors and the fact they can be destroyed during removal are reluctant to pin the blame on to the injectors, yet.

The annoying thing is this car has only done 28,000 mile!

My head hurts!

Thanks to all that have offered advice so far.

Kevin
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Re: Fiat Doblo 1.3

Postby jez1342 » Wed May 22, 2013 5:21 pm

one I've overlooked several times is checking the fuel for petrol contamination. feel, smell and taste it! also have a sniff around the fuel filler.
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Re: Fiat Doblo 1.3

Postby arjen » Wed May 22, 2013 6:21 pm

Fuel check is a good one!
An advise, check the injector leakback at cold and warm engine. Sometimes the injector starts leaking when it's warm.

Also I had a seat altea in the workshop last week. The car was running on 3 - 3.5 cilinders during acceleration. At constant rpm it runs not perfect but not that bad either. Injector readings where pretty much like the same as these are.
That car had a worn camshaft, one inlet nok (cam?) was 50% gone. If you have a wps pressure tranducer (I don't have one.. yet) you can measure that very well.
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Wed May 22, 2013 6:41 pm

Fuel is ok. Car has had this fault for a few months.

Arjen, was your Seat not fitted with the PD engine, where by it will open the injectors via the camshaft?? We don't have the wps I'm afraid. It will go on the shopping list!
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Re: Fiat Doblo 1.3

Postby arjen » Wed May 22, 2013 6:52 pm

Yes it was a PD engine, but the camshaft does not open the injectors. The camshaft only pressures the injector. The actual opening is done electrical, just like a common rail.
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Re: Fiat Doblo 1.3

Postby Robski » Wed May 22, 2013 8:21 pm

The camshaft only pressures the injector

Correct.

The actual opening is done electrical

Is it ? can you elaborate as that statement can be read in a few ways.
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Re: Fiat Doblo 1.3

Postby arjen » Wed May 22, 2013 8:56 pm

@ Robski
I dont know exactly what you mean, but I think you mean the opening is done by pressure, the electric makes it possible to create pressure by closing the circuit in the injector.

My English is not so good (working on it), that's wy I don't explain everything in detail.
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Re: Fiat Doblo 1.3

Postby Robski » Wed May 22, 2013 9:12 pm

I dont know exactly what you mean, but I think you mean the opening is done by pressure, the electric makes it possible to create pressure by closing the circuit in the injector.

My English is not so good (working on it), that's wy I don't explain everything in detail.

Language barrier.........

Yes that's what i was getting at :wink:
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Re: Fiat Doblo 1.3

Postby Valhalla » Wed May 22, 2013 10:38 pm

Dundeeguy wrote:Fuel is ok. Car has had this fault for a few months.

Arjen, was your Seat not fitted with the PD engine, where by it will open the injectors via the camshaft?? We don't have the wps I'm afraid. It will go on the shopping list!


Do you know if there has been any history of misfueling with this car? It could be that it happened roughly a "few months" ago.... White smoke would point towards unburned fuel, usually as a consequence of EGR not closing off properly, but often down to poor injector spray pattern or poor spray pressure or poor spray duration. A pressure sensor in the fuel supply and the fuel return system would rule-out whether the engine is receiving (and returning) fuel from the tank at the correct pressure. These can easily lead to injector spray problems. A check with leak-off equipment might show-up if any of the injectors is unable to return fuel back to the low-pressure system (fuel pressure will be high at the spill port). It might be that No.4 injector is genuinely duff, but it's worth making sure that the feed to/from that injector is good.

Have you checked the cam-timing and lobe-heights, just to be sure that the injectors are pumping up to pressure and at the right time? I think that arjen makes a good point here.
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Re: Fiat Doblo 1.3

Postby Dundeeguy » Thu May 23, 2013 6:30 am

Valhalla,

Thanks for the reply.

Not sure if it has ever been misfueled or not. I don't think the customer has had the car too long, so might have been before they got it.

Cam timing hasn't been checked, or cams checked for wear. However, this is just a normal high pressure engine, not a PD diesel. Fuel pressure to the high pressure pump has been checked and is fine, but a little higher than Autodata says it should be though.

Cheers
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