Audi RS2 injectors, coils, pos, fuel and boost pressure values

[Audi-Porsche Avant RS2]

Hello friend, for my knock problem, that with the other chips now is really very low only when overboost turn on and immediately the ECU correct the knock, I need to know all the values for test this parts and what I must do for make the test:

- Original Audi RS2 Injectors

- Original Audi RS2 fuel pressure

-Original Audi RS2 coils impedance

- Original Audi RS2 POS values if is possible to test it

- Original Audi RS2 boost pressure

Thanks a lot!

Alessio

[Audi-Porsche Avant RS2]

Nobody know these values for test these parts? Thanks!

Alessio

[S2central.net]

Sorry - not enough info... what exactly do you wish to test or measure ?

[Audi-Porsche Avant RS2]

Hello Paul, I need the values of the original injectors of the RS2 like impedance, flow, etc, I need also the values of the impedance of the original coils of the RS2, I think that a good value is between 0,65 and 0,85 Ohm and when the impedance is over 1 Ohm the coil is not so good, I need also the boost pressure of a standard RS2, the fuel pressure of a standard RS2 and is is possible to test also the POS like is possible to test the coils with a multimeter. Thanks a lot!

Alessio

[S2central.net]

I'll dig info out for you - no problem.

Only thing to advise now is that POS is very hard to test.

So are the coil packs - you need a high spec 'conductance meter' to test such low resistance values accurately. If you search for that term here it should give some good hits from old posts.

[Audi-Porsche Avant RS2]

Hello, for test the coils I have already a professional multimeter that can read very low impedance values like 0,1 Ohm.. Thanks a lot for your patience! I need also a complete set of Samco water and boost hoses for my RS2, what can I do for have the kit? Thanks!

Alessio

[Audi-Porsche Avant RS2]

Hello, I have a question, is the original RS2 fuel pumpe made by Bosch? Thanks a lot!
Bye

[S2central.net]

Original pump is a Bosch item - yes...

[S2central.net]

Max boost on stock RS2 at 3000rpm is 1.3 to 1.4 bar. Do this in a test in 4th gear from below 60kph

Fuel pressure regulator spec on RS2 is 3.8 - 4.0 bar (without vacuum)
and approx 3.2 - 3.7 bar with vacuum at idle

Injectors are specified to flow 130-140cc in a 20 second test at static fuel pressure.

Resistance of injectors is 13.5 - 15.5 ohm

I have a graph of RS2 fuel pump delivery rate. Look for flow in excess of 700cc at the return pipe with the pump energised for 15 seconds with a voltage at the pump of 12V.

[Audi-Porsche Avant RS2]

Hello Paul, thanks a lot for your wonderful information. 3,2-3,7 bar with the vacuum at the idle is the fuel pressure that I must read on the fuel pressure gauge when I test the fuel pressure? Where can I put the fuel pressure gauge for test the fuel pressure? If the fuel pressure is correct that mean that the fuel pumpe work good or not?
Thanks!

Alessio

[S2central.net]

Fuel pressure guage must be taken from the fuel rail - I mean 'after' the pressure regulator. With a guage fitted you will see pressure rise and fall with vacuum/boost pressure. The regulator works such that the fuel rail pressure is always 3.8-4.0bar above the pressure within the inlet manifold.

Fuel pressure alone does not test the fuel pump properly... To test it properly you need to measure the amount of fuel being delivered over time... Thats the 700cc figure I refer to over 15 seconds quoted in the manual.

[Audi-Porsche Avant RS2]

Sorry Paul, but I don't understand how test the fuel pump

Alessio

[Audi-Porsche Avant RS2]

I have make some test to the injectors and the result is that the injectors are perfect, now I must try the fuel pressure, check for leak, if there is one is very small, change the pos and the coils and if I don't resolve the problem change the fuel pump. Can a very small leak in the small boost hoses that go from the inlet manifold to the FPR and the ECU cause the knock problem? Thanks a lot!
Bye

Alessio

[S2central.net]

ANY leaks in the air hoses - large or small can cause problems. You need all those small control hoses to be air tight.

As to testing fuel pump - let me try to explain it better... However, be advised of the care required here - you may need an assistant as there will be an open fuel pipe under the car during the test and some chance of electrical sparks as you connect wires to the pump - PLEASE take all the necessary precautions when doing this.


Firstly - You need to activate the fuel pump for about 15 seconds without the engine running. The simplest way to do this is make up a suitable cable - good heavy cable say 2.0 or 2.5sqmm with a 20A fuse in one cable and with quick release connector or switch to turn it on or off. Connect the cable directly from the battery to the two fuel pump terminals. This is why we need a fuse and switch !

Secondly - You need something to collect the fuel. Some sort of 1 liter container. An empty 1 liter oil or coolant bottle with graduations is ideal for measurement... Disconnect the fuel RETURN hose where it goes back to the tank... Some residual pressure will squirt some fuel so be careful of that. When it stops dripping you are ready to test... Place the return hose into the 1 liter container.

Thirdly - Activate the fuel pump with the cable made in step one. Just activate it for 15 seconds... During this time the fuel pressure is static at ~4bar above ambient and there is NO fuel being ingested by the injectors so ALL of the fuel pumped will come to your container.

Last step - measure the amount of fuel in the container after 15 seconds test. It should be over 700cc with nominal 12V at the pump terminals.

To finish off just reconnect the fuel line and disconnect the test cable.

[S2central.net]

I will be doing these same tests myself on my 144k mile original pump to quantify it - and on the Bosch 044 pump that I have had ready to fit for almost two years !!!