Audi A4 1.9TDI B7 BRB misfiring problem

[Jeff1234]

Hi All


I recently purchased the above car; it had defective gears on the throttle body and was giving a P3103 – Motor for intake manifold flap error (V157). Due to this the valve was replaced and the EGR (heavy carbonised) has been cleaned and new seal. Now the engine management light does not come on.


When idle (cold or warm) the engine misfires on an inconsistent basis (perhaps 10 times per minute), also when stationary, if you press the accelerator the engine and body moves\rocks to the right. This is noticeable by monitoring the top of the bonnet.

As I have limited service information on the car, a service was carried out (oil, air, pollen filers) and fuel filter changed. I am using TRIPLE QX Engine Oil - 5W-40 (Fully Synthetic) Engine Oil and Shell V-power diesel.


I am new to VCDS and VAG cars; I have run VCDS on the system and no faults are highlighted.


What can be the cause? If I need to use VCDS to run checks please kindly detail the steps involved.

Thanks

 

[JonSline]

Hi, check torsion value on the timing and MAF sensor values. It's check for over fueling....very difficult to detect on a diesel compared to a petrol. If over fuelling, likely the MAF. If not, likely the timing, check the block 4 value, should be close to zero.


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[desertstorm]

It may be the injector harness need changing. This has a habit of braking down and poor intermittent connections to the injectors result in the symptoms you are seeing. Quite often no faults are seen till it gets really bad.
http://www.germanautopartsdirect.co...ECTOR-WIRING-LOOM-038971600/product_info.html
Has the fuel filter been changed ?. This should be changed if it hasn't been done recently.
Is this the oil you are using ?
http://www.carparts4less.co.uk/cp4l...gine-oil/5w40-engine-oil/?521776031&0&cc5_248
It's only rated 505.00 you should be using a 505.01 at least and preferably a 507.00, It makes a lot of difference with PD engines.
http://www.opieoils.co.uk/c-751-vw-50501-engine-oil.aspx

Don't bother running it on Shell V-power it's not worth the extra money.

 

[JonSline]

Agreed could be the harness. Dark side have then listed not bad prices


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[Jeff1234]

It may be the injector harness need changing. This has a habit of braking down and poor intermittent connections to the injectors result in the symptoms you are seeing. Quite often no faults are seen till it gets really bad.
http://www.germanautopartsdirect.co...ECTOR-WIRING-LOOM-038971600/product_info.html
Has the fuel filter been changed ?. This should be changed if it hasn't been done recently.
Is this the oil you are using ?
http://www.carparts4less.co.uk/cp4l...gine-oil/5w40-engine-oil/?521776031&0&cc5_248
It's only rated 505.00 you should be using a 505.01 at least and preferably a 507.00, It makes a lot of difference with PD engines.
http://www.opieoils.co.uk/c-751-vw-50501-engine-oil.aspx

Don't bother running it on Shell V-power it's not worth the extra money.

Hi,

Thanks for your reply

The oil filter has been changed last week.

The oil is the same as you indicated but the black can, is that ok?

Is there anyway to test/check the harnesses?

 

[Jeff1234]

Thanks, I will look into the timing, is the MAF difficult to test?

I filled up and have done approximately 40 - 50 miles (around town) and I'm now on 3/4 tank. Vpower too! This seems to be drinking too much :-(

Hi, check torsion value on the timing and MAF sensor values. It's check for over fueling....very difficult to detect on a diesel compared to a petrol. If over fuelling, likely the MAF. If not, likely the timing, check the block 4 value, should be close to zero.


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[JonSline]

Sounds Classic MAF to me. yeah. Disconnect it if it drives the same then it's the MAF!


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[desertstorm]

The black can 5w-40 is 505.01 so is for PD engines.=-
Has the fuel filter been changed recently.
To check the harness have a look at block 23 on the measuring blocks.

This is the BIP measurement for the injectors. The readings should be similar and I believe not greater than + - 60.
If they are jumping up and down over + - 60 then this could be the harness.

 

[Jeff1234]

Sounds Classic MAF to me. yeah. Disconnect it if it drives the same then it's the MAF!


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Hi

Disconnected connection to Maf, car runs normal with no engine light.

Am I right to assume maf is dead?

 

[JonSline]

If you went for a drive and it felt the same, you can be pretty sure. Check the wiring there for chafe and bad connections to!

When replacing use a original Bosch one the Chinese Are no good!


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[Jeff1234]

If you went for a drive and it felt the same, you can be pretty sure. Check the wiring there for chafe and bad connections to!

When replacing use a original Bosch one the Chinese Are no good!


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Have not taken it for a drive yet, just left the car running and monitored. I'll go for a drive tomorrow, will keep you posted

Thanks for your help

 

[Jeff1234]

Just ordered the 5po

Have not taken it for a drive yet, just left the car running and monitored. I'll go for a drive tomorrow, will keep you posted

Thanks for your help

Hi
I disconnected the connection to the maf yesterday. This morning I drove 6 miles to work with maf disconnected and the car was not substantially different to drive

It felt approximately 15% more ruff but not as bad as one would expect

Does this warrant a maf replacement?

Also does the map sensor compensate for the lack of information from maf? What is their relation?

Thanks

 

[JonSline]

Maf does air flow. Map does air pressure and temp.

You could try cleaning it. There's several products out there.

If you can borrow one from a mate it's even better!


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[Jeff1234]

Maf does air flow. Map does air pressure and temp.

You could try cleaning it. There's several products out there.

If you can borrow one from a mate it's even better!


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Just a thought, with the maf disconnected, should the car idling not be more erratic or maybe some more obvious change?

Be it a little more ruff, my understanding is that the change would be significant. Maybe I'm getting confused with something else that I may have read

 

[JonSline]

If it's bust you won't see much of a change. If it's ok the change will be huge, like your towing something!

Your consumption is the give away.

Idle isn't hugely smooth on these engine anyway!


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