Audi A4 2.0 TDI Rough idle

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Re: Audi A4 2.0 TDI Rough idle

Postby STC » Thu Aug 18, 2016 9:57 pm

you only have control on duty cycle and not frequency right?
Isn't frequency an issue? Just asking...


Yes & No !!

Frequency will not be too much of an issue when you are activating something directly as our IMV, DRV or any electric motor or solenoid as in this case. Just be cautious of going above 90 / 95% duty as the component may or may not like that for any period of time

It could be tricky if there is a PCB and circuitry between the motor & the connector that we can access to control it. I think some fans are like that where the duty from the ECU is in milliamps, is then measured and the electronics in the fan ECU will then do the magic and control the fan. The Circuitry may get fussy about the Frequency.

Can it do any harm to put a faster / slower frequency to it ?? Assuming the Voltage is Correct (ie not push 12v into a 5v circuit) ?? Can anyone here answer that ?

I have not tried it ?

Have a good look on ebay for PWM Motor Controllers, they are available in varying frequencies.

For the £8 it costs this is a well built tool, good quality and has heaps of Diagnostic Value. Don't forget it has no value on its own, you will need some Correct Wattage and Ohm Resistors or a good decade box to keep the ECU happy when you have the components unplugged and this substituted in.

If you get stuck I can post some links.
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Re: Audi A4 2.0 TDI Rough idle

Postby Fanstiintza » Sun Mar 19, 2017 12:46 pm

Hi. I have the same problem with a similar car and nobody knows what's the problem. i been in 3 garages and change 3 injectors but the problem is still there. Can you tell me what is DRV means? Thank you
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Re: Audi A4 2.0 TDI Rough idle

Postby STC » Mon Mar 20, 2017 3:20 pm

i been in 3 garages and change 3 injectors but the problem is still there.


Why is it that the Injectors are always first in the firing line ???


tell me what is DRV means


I believe it is a German (Bosch) Acronym. In English it refers to the "Fuel Rail Pressure Regulator / Valve.

As far as I know these come complete with the Rail and Pressure Sensor at the other end and cost about £1000 Shiny English Pounds. A bitter pill to swallow but worthwhile if it fixes it.

The Drama starts when it does not fix it ?? You cannot diagnose a fault based on another mans findings on a similar car.
You need to find someone that has the correct tooling and knowledge to devise and follow a methodical test plan.

You could post your location and ask for a recommendation here - but that's your choice.
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Re: Audi A4 2.0 TDI Rough idle

Postby Fanstiintza » Thu Mar 23, 2017 8:50 am

I change the valve with a friend, it cost me 165 pounds...not to expensive after I spend more then 1000 for 3 injectors. The car is back to normal.
I live in Birmingham if you know any good garage for the future. Thank you
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Re: Audi A4 2.0 TDI Rough idle

Postby STC » Thu Mar 23, 2017 8:41 pm

Good to hear you got a fix :D :D

Not wishing to rain on your parade but please bear in mind that the new regulator should be adapted/calibrated to your vehicle with a diagnostic tool for it to function absolutely correctly in the long term.

not to expensive after I spend more then 1000 for 3 injectors.

It is a shame that our "colleagues" in the garage trade continue to Rubbish our reputation. Read below and I am sure you will never have those problems again. Tell your friends if you are served well.

May I ask ? Did you check the Qualifications of the Technician that Diagnosed the fault. For instance http://www.imiregister.org.uk/search?fh ... Birmingham

I live in Birmingham if you know any good garage for the future. Thank you


Have a chat with Geoff Dyed at https://www.eveshamgarage.co.uk/diagnostics.php

(He taught me - at Masters Level - if that holds any weight for you)
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