Hyundai Santa Fe 2.0 Diesel 2004/5 - Intermittent Fault - black smoke and loss of power

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Thu 20 Aug 2015 19:24
Hyundai Santa Fe 2.0 Diesel 2004/5 - Intermittent Fault - black smoke and loss of power - AndrewR

For a few months now, I've had an intermittent problem with black smoke from the exhaust coupled with a reduction in power. Recently it's become less intermittent! Motorway driving is fine as even with the problem happening, I can gradually get the car up to 60mph, put it in cruise control and gently get home. However come off the motorway and try to get up and down steeper hills, and it really struggles. My local garage (here in France, and NOT a Hyundai dealer), did a diagnostic test and identified a "problem" with the Air Mass Sensor - so we replaced it. All was well for a couple of weeks then the problem came back. Garage said new diagnostics test showed "No Faults". They suggested perhaps a problem with dirt in the fuel (diesel, by the way). This weekend, I changed the air filter and the fuel filter under the bonnet and, although I did a 100 mile round trip on the motorway yesterday with no problem, today the problem has reared its ugly head once again.

Any help/suggestions greatly appreciated!

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Thu 20 Aug 2015 20:49
Hyundai Santa Fe 2.0 Diesel 2004/5 - Intermittent Fault - black smoke and loss of power - hardway

Just had 5 cyl diesel Merc in today with exactly the same symptoms,

though customers car also emited clouds of black smoke at lights or junctions when stopping.

A leak back test on the injectors was inconclusive so I went to live data,

though no "MIL" was on and no codes stored live data showed an "odd" waveform pattern on the MAF,

and here's when luck,

or good eyes came in.

while removing the AFM I noticed the ducting to the turbo looked loose.

So I suggest a check on all induction hoses for leaks,clip security.

Any air leak after the AFM is going to throw off the fuel delivery ratio.

Or if your garage has it a smoke test of the induction tract.

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