M177 and M178 fuel filter issues

[UKGTC]

As we all know many modern engines run super high fuel pressures through injectors with tiny jets. I understand this is to aid fuel efficiency and power but unfortunately this comes at a higher risk of failure, especially from dirty, contaminated or old fuel. Having done a bit of digging it seems there are no fuel filters on the M177 or M178 engines and instead a gauze built into the lift pump. I have not idea how small the filtering holes are in the gauze but I do know filters have such a large surface area that they are capable of filtering out very small particles.

If this is correct and there is not separate replaceable fuel filter it seems a poor design. Previously in a stage 3 RS3 I had an Injector Dynamics filter system and I am wondering if this could be added to the fuel system on one of these V8 engines and is there any known risk. I can't for the life of me understand why AMG didn't have a filter that could be easily accessed and changed yearly.

This is what I have found for the ID F750 that I used for injectors that were capable of running over 1000hp:

The Next Step in Filtration​

The ID F750 is the first performance filter designed to meet strict OE filter requirements, namely Bosch’s specification for electronic fuel injectors. It is the result of substantial research invested in improving the service life of our injectors.

In addition to improved filtering, the ID F750 offers numerous features designed to increase performance and function.

Basic Specifications​

Nominal Flow Rate – 750 l/h @ 7.5 kPa (1.1 psi) pressure drop. 1000 l/h @ 13 kPa (1.9 psi) pressure drop
Maximum Fuel Pressure – 10.0 Bar (145.0 psi)
Fuel Compatibility – Compatible With All Known Fuels
Fluid Connection – SAE -8 O-Ring Barb
Weight – 700g

Filter Efficiency​

Electronic fuel injectors are built to precise dimensions, measured in microns. The smallest of particles can increase wear, or even destroy a fuel injector. Bosch provides a specification for protection of electronic fuel injectors, which is a minimum capture efficiency of 87% at 5 microns, and 100% capture efficiency at 35 microns. This means that the filter will capture at least 87% of all particles 5 microns and larger, and 100% of all particles 35 micron and larger. The filter element in the ID F750 meets that specification, and does so without undue flow restriction.

Flow Restriction vs Contaminant Load​

The ID F750 is designed to hold a high level of contaminant while maintaining low restriction to flow. This is accomplished with a highly efficient filter element, designed with low pressure drop in mind. At a flow rate of 750 liters per hour, the ID F750 will hold five grams of contaminant, the equivalent of approximately one teaspoon before requiring replacement. Higher flow rates are possible, but will require more frequent filter changes, depending on the cleanliness of your fuel system.

 

[sgregory124]

I’m on my second car with an M177 and have never had (or heard) of any issues relating to fuel/filtering or lack there of…..

 

[UKGTC]

I’m on my second car with an M177 and have never had (or heard) of any issues relating to fuel/filtering or lack there of…

I hope to never have an issue but the majority all injector issues are related to getting blocked and it doesn’t help that there isn’t a replaceable filter like most modern cars have.
I’ve read on other forums where owners have had injectors stick in the open position resulting in a whole in the piston after trying to compress an excess of fuel requiring an engine rebuild.

 

[UKGTC]

On a related note how often does anyone clean the gauze filter in their fuel lift pump and is it ev er n part of a maintenance schedule?

On my previous RS3 there was a gauze filter in the DCT that my independent cleaned but wasn’t part of the dealer servicing despite having caused known problems.

 

[ToeKnee]

Not your engine, mine is the M278 but the in tank fuel filter in mine is a proper filter that needs changing every ten years. It's not a simple job and is part of the sender unit, iirc.