Passat(form hell) 1.9 tdi AVf engine misfire

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Passat(form hell) 1.9 tdi AVf engine misfire

Postby grunf1976 » Sat Nov 19, 2016 3:06 pm

HI,
I dont know if this is the right place to put this but I would like to share this in hope that it would help someone.
Few days ago I had a Passat brought to my shop because of misfire on idle that has been going on for TWO YEARS! That how long the owner had this car. He took it to number of shops and it still misfires on idle. So normally first thing I did was to scan for codes. It had a code for nr.1 injector wiring. So knowing that that is a known fault with these I pull the valve cover an immediately repaired the wiring thinking that should fix the problem. To my surprise although the car ran somewhat better, the misfire was still there. Ok... then I took a look at the rough running values. they were all normal, but the mvb for the injector adaptation showed that it wasnt getting enough fuel. Checked lift pump in the tank it was ok. checked high pressure pump it was ok????
The warmer the car was, the worse the misfire got, but when you touch the throttle it revs up normally. Next I did a compression check. It was Ok. At this point I was totally confused. Everything said that car should run ok, but it wasnt.
So I took PIcoscope and decided to see what was gong on with injectors. By that time the car was at normal operating temperature. Scoping one injector at a time I found that injector 3 was cutting out at same time that i had misfire, but still no change at rough running values. So I got to the point where noting made sense. I have done tons of these and I know them inside out, but this one had me upside down.

Then I decided to take a closer look at ECU. Standard Bosch EDC 15. So I opened it up and tested outputs for injectors and couldnt find nothing. I wouldnt let this one beat me !!! I swapped places of electornic parts from that output( that I could remove) to output's for other injectors and other way around hoping that the fault would be seen on the Pico.
And you guessed it! Nothing, no change. At that time I was 60% convinced that my problem was the ECU. So I decided to get a replacement one and test my theory. So I called a friend that had a known good car an asked if I could borrow his ECU to test it on another car. So as soon as I put replacement one in the car ran great! Placed misfire one on my friends car and his car started misfiring.
So I was so happy and i thought I won.

So now to get replacement ECU. I opened VW's parts catalogue and puled the number of ECU. I just wanted to be sure that everything is the same so I dont make a mistake. The number was the same, but I noticed that it stated that It works ONLY with injectors that have certain part number. So ok, lets check that also. To my surprise injectors that were inside weren't the ones that should be! SOMEONE PLACED WRONG INJECTORS IN THE ENGINE!!!

The thing is, first generation had injectors that had output of 2ccm# of fuel and the other had 8ccm#. So the software in ECU was different. So i found matching ECU for those injectors and that solved the problem finally.

Now car works fine. I really hope that this will help someone someday and that this wasn't boring to read

All the best,
Mickey
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby Tronic » Sat Nov 19, 2016 8:29 pm

Thanks for great write up grunf1976!

Very interesting! Worst scenarios are usually created by the "mysterious someone" that has been there before...

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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby Technician » Tue Nov 22, 2016 11:14 pm

Thanks for sharing your experience with us :) .

Many years ago, about 12 I think I worked for Vauxhall and can share two experiences I remember from back then.

1 / A Vauxhall Vectra came in with a noisy engine at idle and misfiring, my first instinct was to check spark plugs and coils, the foreman having worked for Vauxhall at that time 13 years advised that I should plug in Tech 2 and carryout a software update, I thought software update?

Brand new to me back then, so I did and after loading the new software in the ECM of the Vectra, the misfire and noisy engine running were completely gone, I was amazed.

2 / A Vauxhall Corsa, brand new still in the first twelve months of its warranty, the owner was using the car as a professional driving instructor, he advised that his learner drivers while starting to drive off from rest kept stalling the engine, he knew the engine had a fault but thought it was the clutch. The garage staff "younger ones" many of them road tested the car and advised there was nothing wrong, until one day the reception asked me to road test the car, initially I also found nothing wrong, then I started to drive it like a learner driver, hence I started from a parked position and slowly from rest accelerated the car and then the engine misfired, you could drive through it and the misfire did not return while driving. Using Tech 2 I recorded live data and replayed it on TIS and found using the graphing mode that the EGR valve was operating outside of normal parameters at that time, I thought faulty EGR valve, but after talking to Vauxhall Technical staff at technical headquarters they decided that the problem was the ECM software, which required an update, however was not available at that time because it had not been written.

Recent CDP training courses I have attended have advised about modern vehicles now with Ethernet connection ports fitted that now link with the vehicle manufacturers databases for a direct linkup to update software in the vehicles ECM's.

Another example of software updating....

A Ford Fiesta 2011 on-wards was serviced by a garage and after servicing and adjusting the rear drum brakes, nothing changed, the technician experienced total brake failure when driving off the ramp, after re-checking all his work and finding nothing wrong, he contacted technical help and they advised that after adjusting brakes the vehicles ECM required a software update to tell the car that the brakes had been adjusted, you can read more about this at Ford Etis if you have access. My feelings about these types of problems are that they are dangerous, that defective condition is no different to me than driving a vehicle at 70 MPH on the motorway then the code P1576 appears with total loss of throttle pedal response, total disaster in my opinion.
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby Dcunning35 » Wed Nov 23, 2016 12:35 pm

Technician ,your fiesta scenario doesn't add up . Basically the abs software update was to address aeriation of rear brakes as the solenoid valves originally don't cycle during dynamic self test. This is due to the car sharing the platform with the Mazda 2 and Mazda didn't feel it necessary as it added to nvh issues.
With the update also came a revised bleedmaster funtion in ids Tha supports dynamic rear brakes adjustment.
If earlier build date vehicles also require the abs controller replacing as it originally didn't support reprograming serially.
Regards
Danny
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby STC » Wed Nov 23, 2016 4:54 pm

My feelings about these types of problems are that they are dangerous, that defective condition is no different to me than driving a vehicle at 70 MPH on the motorway then the code P1576 appears with total loss of throttle pedal response, total disaster in my opinion.


P1576 Accelerator Pedal Failure and total loss of throttle response. Have you considered the alternative ? Very easily an uncontrollable, runaway car and / or engine - Now that would or could be a total disaster. Why would you expect a VM to design it any other way? - makes no sense. (it is probably a Legal Requirement)

With the introduction of adaptive cruise, lane assist etc. These technogies may allow for alternative, less rigid redundancy stratagies - or not, as we are slowly being warmed up to the driverless, connected car.

At 70 mph, in the fast lane of a Motorway suffering throttle pedal failure would give you more than enough time and momentum in the vehicle to enable you to indicate to other road users your intention to drift on to the Hard Shoulder to safety. The only obstacle would be the mindless, selfish, idiots (they are out there in abundance) who will not give way, worse still, will commit the illegal act of undertaking, hindering your efforts of reaching and stopping in a safe place.
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby Technician » Wed Nov 23, 2016 5:32 pm

STC wrote:
My feelings about these types of problems are that they are dangerous, that defective condition is no different to me than driving a vehicle at 70 MPH on the motorway then the code P1576 appears with total loss of throttle pedal response, total disaster in my opinion.


P1576 Accelerator Pedal Failure and total loss of throttle response. Have you considered the alternative ? Very easily an uncontrollable, runaway car and / or engine - Now that would or could be a total disaster. Why would you expect a VM to design it any other way? - makes no sense. (it is probably a Legal Requirement)

With the introduction of adaptive cruise, lane assist etc. These technogies may allow for alternative, less rigid redundancy stratagies - or not, as we are slowly being warmed up to the driverless, connected car.

At 70 mph, in the fast lane of a Motorway suffering throttle pedal failure would give you more than enough time and momentum in the vehicle to enable you to indicate to other road users your intention to drift on to the Hard Shoulder to safety. The only obstacle would be the mindless, selfish, idiots (they are out there in abundance) who will not give way, worse still, will commit the illegal act of undertaking, hindering your efforts of reaching and stopping in a safe place.


STC, I use the motorways quite a lot travelling to and from CPD events, I agree with your views about drivers on the roads, however, in my opinion any designer who designs a throttle pedal circuit to completely fail in this example having 3 power supplies, 3 ground returns, and 3 signatures, using from seems to be a COMMON POINT to supply ALL circuits is an absolute idiot in my view. They might of just as well put on potentiometer in there instead of three.


Dcunning35 wrote:Technician ,your fiesta scenario doesn't add up . Basically the abs software update was to address aeriation of rear brakes as the solenoid valves originally don't cycle during dynamic self test. This is due to the car sharing the platform with the Mazda 2 and Mazda didn't feel it necessary as it added to nvh issues.
With the update also came a revised bleedmaster funtion in ids Tha supports dynamic rear brakes adjustment.
If earlier build date vehicles also require the abs controller replacing as it originally didn't support reprograming serially.
Regards
Danny


Danny, you may understand more about it than I, myself not having experienced this problem to date, however I am just relaying information from Delphi who informed us at the CPD of the problem, nobody spoke up to change the views of the presenter telling us about it, so at face value I am taking him at his word.
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby Dcunning35 » Wed Nov 23, 2016 5:55 pm

I just didn't want anybody being misguided that's all and it isn't an authored tsb so isn't displayed on etis , The update was available in dealer linked to an etis ids sbd routine or the fdrs network.
Apologies if this thread has lost its original clarity but good call on the passat that was a good find and will be something to look out for.
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Re: Passat(form hell) 1.9 tdi AVf engine misfire

Postby STC » Wed Nov 23, 2016 9:23 pm

good call on the passat that was a good find


Indeed Mickey, that dogged determination deserves a happy ending. :D :D :D Hope you get paid well !

Dont you just hate these monkeys that put wrong parts on cars, worse still the ones that mess around with software (not aimed at the good ethical tuners), the ones that delete fault codes etc.

I dont think they know, or even care, how much Headache, Heartache & Pain they cause. How do you get it in to their thick heads (without an AK47) that they have not fixed the car. Just made it harder to fix.
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