Audi A4 Tdi 130 Avf motor

corcaigh1

Hi folks,

having an issue of late with my 2004 audi a4 tdi motor. From starting on cold the motor is hunting on idle (see vid) and there is also white smoke from exhaust with a rancid smell.

Some history:


170,000 miles
Genuine coolant temp sensor, air filter, cabin filter replaced 2 years ago.
Genuine Maf sensor changed one month ago.
Mann Fuel filter changed 2 weeks ago.
Genuine fuel injector harness changed this week.

Any ideas what this issue is?


Thanks in advance

Cerebrum

Sounds a bit like an EGR issue (hopefully not head gasket).

Has the coolant level dropped slightly?

corcaigh1

Cerebrum wrote: »

Sounds a bit like an EGR issue (hopefully not head gasket).

Has the coolant level dropped slightly?

Thanks cerebrum, no the coolant hasnt dropped at all. What could be the issue's with the EGR?

scannerd

egr cooler can leak coolant into the engine, would cause rough running and smoke / exhaust smell, can also get stuck open causing rough running at low rpm.

white smoke could be a fuel or compression issue - would get a relative compression test as its quick easy test

also any codes?

corcaigh1

scannerd wrote: »

egr cooler can leak coolant into the engine, would cause rough running and smoke / exhaust smell, can also get stuck open causing rough running at low rpm.

white smoke could be a fuel or compression issue - would get a relative compression test as its quick easy test

also any codes?

Interesting, yeah so when driving the car today it went into limp mode for the first time ever in my few years of ownership and the engine management light came on also.

Scanned it with VCDS and showed up fault: 17564 Manifold pressure sensor (G71) - P1156 - 35-10 - Open/Short to Ground - Intermittent

Cleared it and went for another blast and got no engine light but intermittent power delivery loss and a whistle when backing off the accelerator

Worth pointing out that fuel economy has dropped to about 30mpg also...some strange behaviour from the car of late so be time to book it in for an engine health check!

scannerd

fault with the manifold pressure sensor could lead to over fueling = white smoke

Cerebrum

corcaigh1 wrote: »

Interesting, yeah so when driving the car today it went into limp mode for the first time ever in my few years of ownership and the engine management light came on also.

Scanned it with VCDS and showed up fault: 17564 Manifold pressure sensor (G71) - P1156 - 35-10 - Open/Short to Ground - Intermittent

Cleared it and went for another blast and got no engine light but intermittent power delivery loss and a whistle when backing off the accelerator

Worth pointing out that fuel economy has dropped to about 30mpg also...some strange behaviour from the car of late so be time to book it in for an engine health check!

Those are all faulty MAP sensor symptoms, so no real need for the health check.

BOSCH: 0281002401 is the MAP sensor

corcaigh1

Cerebrum wrote: »

Those are all faulty MAP sensor symptoms, so no real need for the health check.

BOSCH: 0281002401 is the MAP sensor

Yeah so I replaced the map sensor yesterday "cerebrum" and that sorted the issue, running perfect now cheers!

Still have the issue with the motor hunting on startup though, hell of alot of white smoke this morning on startup also.

I cleaned the egr and manifold over a year ago so im worried now its gotta be the cams or injectors causing that behaviour on startup....

The Red Ace

had an issue like yours a few years ago with hunting on tick over and power loss, turned out it was water in the diesel so might be worth checking the fuel filter

giesha

hi corcaigh1. how do you doing.?

i as the same car a4 2004 1.9 tdi.

you say you changed the map sensor.

can i ask, were is it located.?

my car is plenty of power while its cold then when it gets normal operating temp its goes basicly into limp home mode.
i scanned it & the code is for the g71 map sensor, but im not familiar with this sensor location.

any help be great.
thanks coraigh1

corcaigh1

This is the VW Passat but same Tdi motor and location for the MAP sensor, hope that helps!

giesha

hi corcaigh1.

thanks for that mate. yes i thought so, i think on the 2.5 its behind the passenger head lamp, & i found some were that they said back on top of engine, i go out this weekend & take look at the car (not my car, good friends car).
thanks for for that any way corcaigh1.

did you get your car sorted out.?

corcaigh1

giesha wrote: »

hi corcaigh1.

thanks for that mate. yes i thought so, i think on the 2.5 its behind the passenger head lamp, & i found some were that they said back on top of engine, i go out this weekend & take look at the car (not my car, good friends car).
thanks for for that any way corcaigh1.

did you get your car sorted out.?

No prob, I did indeed she's purring away nicely!