Hello,

I have a vw golf 1.9 tdi engine code ahf .
when the throttle is briefly blipped or whilst driving under normal conditions it blows out a puff of black smoke from the tail pipe.
i have recently replaced the,

Egr valve due to the diaphragm be split and not holding vacuum
and also the air mass(maf sensor) as im getting a reading of 580-850 mg/s of air whilst the desired value is much lower at 280mg/s.
and replaced the small vacuum pipes goin to the 2 solenoids and egr valve.

There are no current codes appearing on the diagnostic machine just the live data do not add up as im also getting a slightly higher boost at 1030 and it should be about 980hpa.

ive put a vacuum gauge onto the wastegate vacuum pipe and i can feel the pipe moving and holding vacuum.

When checking the voltages going to the maf sensor there all ok however when i check the signal wire coming out from it im getting a slightly higher reading at 1.8v at idle when it should be 1v.its had two recon bosch sensors fitted and no difference so is this not the cause?or should an original part make any difference?

I have put a ohms resistor into the signal wire at the maf sensor back to the ecu and if i put 40k ohms on the circuit i get a proper reading and car doesnt chuck out hardly any smoke.

ive checked the earths and all ok..

seems to be a complicated fault for me.

can anyone help?? cheers..