The trend in modern automotive engineering and architecture of assemblies and units is to bind as many consumables as possible into one unit, solder, glue, make them indissoluble. This is understandable. It is more profitable for the manufacturer to sell parts in modules, not individually. It is more advantageous for us to replace one gasket, than to change the whole assembly. The same story with the gas pump on the Skoda Octavia III (A7).
On almost all modifications, the fuel module can not be disassembled and repaired. Filter clogged – change the module completely. But that was not the case. Today we are going to find out how to clean fuel filter on Octavia III and make dismountable and serviceable pump.
Fuel pump noise in Octavia III. What to do
Quite a common problem is the noise of the gasoline pump in the last years of production Octavia III. You can and should fight it
Fuel pump noise in Octavia III is caused by a number of reasons. As a rule, the fuel filter is to blame. It gets clogged, the fuel does not enter the pump in the required volume, it overheats (because it is cooled only due to the gasoline in the tank, it is also lubricated by it) and gradually fails. In such cases there is only one way out – the replacement of a complete gas pump, that is the replacement of the fuel module. And this pleasure is not cheap.
Fuel pump for Octavia III. Part numbers and prices
For example, the fuel module for an Octavia A7 with a 1.8 TSI engine will cost us from $45-55. That’s not much fun. And you still need to choose the right gas pump for your engine type. It is not difficult to do.
For instance, the catalog number of a fuel module for an Octavia A7 with a 1.4 liter turbocharged TSI motor is VAG 5Q0 919 051 M. It costs much or little – $190, VAG-original. The Bosch pump with part number 00580200382 you can buy for $135, and the Italian equivalent Meat & Doria 077017 only for $90.
The situation is as follows:
Their prices are almost the same – from $100 to $190, depending on the manufacturer.
Signs of fuel pump and filter failure on Octavia III (A7)
If the pressure in the fuel system drops, the ECU can throw a lot of errors, and in addition the engine will behave inadequately because the mixture is too lean
The main symptoms of the gasoline pump and filter malfunction in one way or another lead to a lean mixture and a drop in pressure in the fuel rail.
Recall that the normal pressure in the ramp is 3 bar at idle, about 4 bar with the return hose removed and about 6 bar with a clamped return hose. Pump capacity is 90 l/h.
Hence all the signs of a faulty petrol pump and a clogged fuel filter:
- Sags on acceleration.
- Difficult to start the engine, especially when cold.
- The car may jerk at high or medium revolutions.
- Deterioration of dynamism, inertia, engine stalls.
- Delayed engine response to the accelerator pedal.
- The engine may jerk and stall in transient modes.
Of course, there may be other reasons for such engine behavior (e.g., ignition coil malfunctions, spark formation skips, timing mechanism desynchronization).
But it is often about the gasoline pump, especially in cases where before starting the engine when turning the ignition key the gasoline pump attracts attention with an unusual noise. The work of cleaning and diagnosing the gasoline pump is not too difficult and will take two hours at most.
How to clean the in-tank fuel filter in an Octavia III
Since the design of the fuel module of Octavia III (A7) is theoretically monolithic, there is no need for VAG to produce spare parts. So we’ll make it ourselves and figure out how to remove the gasoline pump and filter assembly.
The problem in diagnosing faults of the fuel module and a clogged filter, in particular, is that the breakdown does not happen suddenly, and the symptoms build up gradually. Another problem is that official service stations do not clean the filter and repair the gasoline pump motor, but replace the module as a whole.
We are already familiar with the price of a fuel module, and as practice shows, you will have to pay the price of a spare part for the work. Therefore, it would be logical to save those $300 and do the job yourself.
The design of the fuel module is such that the filter is a grid with a filler, which captures the dirt that gets into the tank. As far as we still have gas stations that fill up the tanks with whatever the hell it is, at the mileage of 40-50 thousand there is quite a lot of garbage there. At least, enough to completely clog the filter screen. Let’s clean it ourselves.
- Let’s take off the back seat.
- Under it we find the plastic hatch of the gas pump.
- Open the cover and see the end of the fuel module, to which are connected the terminals with wires and fuel lines – supply and return.
- Do not rush to remove the pump, first let’s depressurize the fuel system. You can’t do it by removing the fuse of the gas pump, it doesn’t work on Octavia III. The engine will not start.
That is why we remove the terminal from the petrol pump cover, start the engine and wait until the fuel is depleted and the engine shuts down by itself. The pressure is released.
- Now carefully remove the fuel line connectors by pressing the catch on the side.
- Just in case, put a clean rag near you, there may be gasoline residue. Now that the fuel lines are disconnected, you can remove the gasoline pump fixing washer. To do this, carefully turn it counterclockwise with a screwdriver and light tapping.
- Carefully remove the gasoline pump from the tank and remove the o-ring, being careful not to damage it.
- To disassemble the module housing, drill out the three plastic rivets with a 6 mm drill bit and drill through the housing in these places.
- Disassemble the housing and only now you have access to the mesh filter. Assess its condition and the condition of our fuel at the gas stations.
- The filter will be washed in solvent and injector or carburetor cleaning fluid. It does not matter which liquid we use, they are all aggressive and clean the filter well enough. Wash the screen until the cleaning solution is clear and the screen is visually clean. Dry and blow out the filter.
- Take three bolts Ø 5 mm in length of at least 40-45 mm.
- Assemble the fuel module and screw in our kolhozny mount. Don’t forget to put lockwashers under the washers on the new bolts.
- Reassemble the fuel module in the reverse order, checking the condition of the tank beforehand. If it is full of garbage, drain the remaining gasoline and tidy up the tank. When reassembling, try not to bend the float of the fuel level sensor.
Theoretically, you can wash the filter without disassembling it. But the efficiency of this method of cleaning is very questionable. Also, when working with the fuel system, especially with an open tank, it is better to remove the terminal from the battery in advance. We do not need sparks here. Have a good job and clean gasoline!
