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

[Audi-Porsche Avant RS2]

Thanks a lot for you patience and instructions Paul, I will made the fuel pump test in the next days, today I have mount a 4 Bar FPR from a ABY and the knock problem is about 0 I have a bit of misfiring in the idle when the engine is hot, but really a bit, the engine run well now and the boost pressure is about 1,6 bar, some days ago was about 1,7 bar but I was in motorway in 6 gear, Saturday I have a meeting with a Porsche Club and so I can test the car well and also check for errors codes in the ECU. Probably before I had a bit of leak in the small hose that is connect from the inlet manifold to the FPR hose and ECU hose, now I think that I have resolve this problem, but I prefer test also the other parts that can cause my problems.
Thanks!

Alessio

[Audi-Porsche Avant RS2]

Hello friends, I have a question. Is 0 580 254 040 the correct Bosch code for the RS2 fuel pump? Do you know if exist a FPR with more of 4 bar? Thanks a lot! Bye

Alessio

[S2central.net]

When was your fuel filter last changed Alessio ?

Its a real bitch of job on the AVant, but I wonder is a clogged filter - or aging pump the possible cause for the lean running that is giving you knock at high boost.

Have you checked the lambda probe is healthy - you can see this on VAGCOM.

I would NOT mess with higher than 4bar FPR to fix a fuelling problem unless you absolutely must - higher fuel rail pressure puts additional strain on the pump and the lines. Yes there are Bosch 5bar and variable FPRs from places like 034 - but you need to root cause this fuelling issue. Messing with FPR is not the proper fix.

I don't have a cross-reference on the Bosch parts - you should contact a local Bosch agent to check that for you - they may have a resource to check against Audi number.

Another to check is that the fuel pump is getting at least 12V at the terminals... Corrosion or bad contacts can reduce that and giving less fuel as a result.

The other main sensor to test in a lean running issue like this the MAF - its hard to test properly - so try and borrow a known good one for comparison.

And of course - it might be just an air leak where the engine is drawing in some unmetered air - running lean as a result but not leaking so much that it throws up faults or cutoffs...

[Audi-Porsche Avant RS2]

Hello Paul, my fuel filter is new and original I have already change it about one month ago for this problem and not result, the old filter was original too and good, my RS2 is really in good condition for a 240000 Km car the owners before me has always serviced this RS2 in Audi service with original parts and I service it with original parts too or parts made by the same factories of the original parts like Bosch, Beru, etc. I have a new and original MAF, change for this problem and the problem is always present, I have change the lambda sonde with a new one made by Bosch with the code for the RS2, I have change also N75 and pop off valve with originals parts, I have try G62 and G42 sensors and are good, the only sensors that I have not test are the F76 and the other sensor that is near the F76 in the water rail because I don't know how test these sensors and are also in a very bad position for test, also the valve of the oil, I don't know the correct name, is the one near the electric water pump, is new. The spark plugs are the Bosch F5PD0R and are in good condition, have only 10000 Km, I have also new coils to spark plugs connectors, the only parts that I have not change and test are the POS, I have change and test also the coils with some others that I have and the coils that I have now under my RS2 before was under my S2 Coupe ABY, my S2 Coupe ABY when the engine is hot have a good idle with not misfiring impression the RS2 instead when the engine is hot at the idle have not a good idle for me, I have the impression that sometimes one cylinders have a very small misfiring but I don't know what can cause this and if this problem can cause also the knock problem immediately when the overboost turn on because now the engine run well also in overboost and the knock is really a bit immediately when the overboost turn on, the knock now is about one second when the overboost turn on, then the ECU correct the problem I think. A very small leak in the boost hoses can cause the knock or is possible that I have a small leak in the hose between the MAF and turbo inlet? I need a complete Samco kit because run with 1,7 bar of boost pressure with the original RS2 hoses is not safe for me

Alessio

[Audi-Porsche Avant RS2]

Hello, on 2 June I will be in Monza for another trackday with my RS2 and all models of Porsche, included some 997 GT3RS I have decided that I must resolve before the problem of the little knock when the overboost turn on, about one second knock and now the car run very well, but for a trackday I want that the car is perfect, I will mount also a complete set of front and rear Koni Sport Adjustable shock absorbers and H&R springs, I want try the complete H&R set but the dealer has tell me that is not good for road use of the car, so I have buy the Koni + H&R, I will post some pictures of the work. Now I have a question, is for you the original RS2 fuel pump good for a RS2 with the original turbo and the boost pressure in overboost at about 1,7 bar? And the original FPR and Injectors? I have read that the original parts of the RS2, like injectors and fuel pump can supply also 400 hp, but I'm not sure of this. What do you think?
Thanks a lot!
Bye

Alessio

[S2central.net]

Only way to tell if the RS2 fuel pump is capable is to flow test it with fuel pressure of 5.5bar (your stock 3.8bar FPR plus 1.7bar boost). I personally think it could be marginal at this level.

One easy way to improve efficiency of the fuel pump is wire up a relay to power it from the battery with short / fat cables to minimise the voltage drop... Any fuel pump with ~14V across it will flow more fuel than one with ~12V. This might be enough to cure some possible fuel starvation you have. Although - maybe its just mapped with too much advance for that boost level when running in hotter air temps ?

[Audi-Porsche Avant RS2]

Sorry Paul, I don't understand what do you want mean at the end of the post. Can you explain it? Now I want mount a new fuel pump, if possible the original for the RS2, but I don't know if I can have always the knock problem if the problem is the fuel pressure too low or not. Now I have a 4 bar FPR from ABY, but always a bit of knock immediately when overboost turn on, then the knock sensors and the ECU correct it I think and the engine run well. I wait also the new coils from Beru with the POS integrated and the kit for check for boost leaks from AndyP, if I have a boost leak I think that is possible in the hose between MAF and turbo inlet or in the small hoses that are connected also to the FPR and ECU boost pressure sensor.

Alessio

[S2central.net]

If going to trouble of renewing the fuel pump - drop in Bosch 044 pump instead - better flow than RS2 item. Was the ECU remapped for a particular setup that has changed maybe ?

Coilpacks could be the root cause too of course - mine give some issues too - I am overdue a new set of coils. What coils are you choosing with integrated POS ?

[Audi-Porsche Avant RS2]

Hello, the coils are here: http://cgi.ebay.de/ws/eBayISAPI.dll?...:X:RTQ:DE:1123
What do you think about it? For the chips that are in my ECU, before that I try the car with a boost gauge I think that was the original Motronic chips, I mean the first one that I have from when I have bought the car in February 2006, because in December 2006 I have mount other chips and with this other chips that are made from PKM, the boost pressure in overboost is about 1,5 bar but the knock problem is really long, with the other chips with the overboost pressure at 1,7 bar the knock problem is really short, only one second I think, immediately when overboost turn on. I don't understand how is possible that with less boost pressure I have more knock problem, is possible that the ECU cut the overboost pressure at 1,5 bar with the PKM chips for the knock problem, but this chips have a higher overboost pressure or overboost pressure higher that 1,7 bar with only chips and not hard wastegate spring is impossible with the original RS2 turbo? Mount the 044 Bosch Motorsport pump instead of the original RS2 pump is difficult or not? And what do you think about 4 or 5 bar FPR instead of the original 3,8 bar FPR? Thanks a lot!
Bye

Alessio

[Audi-Porsche Avant RS2]

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Alessio

[Audi-Porsche Avant RS2]

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Alessio

[Audi-Porsche Avant RS2]

Hello, where can I find the fuel pressure value that I must read if I put a fuel pressure gauge between the fuel out that come from the fuel filter I think, so the fuel pressure generated by the fuel pump and the fuel rail inlet? Is this value the same when the engine is at idle and during work or not? Thanks a lot!

Alessio

[Audi-Porsche Avant RS2]

Hello, today I have done the fuel pressure test with a fuel pressure gauge. I have connect the fuel pressure gauge on the return fuel pipe that come from the injectors rail, is this correct? The fuel pressure when the engine is cold at the idle is about 4 bar, when the engine is hot at idle is about 3,8 bar, I have a 4 bar FPR, not the stock 3,8 bar FPR under my RS2, I have make the test also with the overboost and boost pressure, with the overboost pressure of about 1,6-1,7 bar the fuel pressure is about 5,6-5,7 bar, so with a 4 bar FPR I think that the values that I have measure are correct, what do you think about it? Now I want test also the fuel pump flow, then I have make all the possible test on my RS2 for find what cause the 1 second knock problem immediately when overboost turn on, I have see with the overboost test in 4th gear at 2000 rpm with the gas pedal at floor that also the N75 work because the boost pressure gauge oscillate for the overboost time between 1,5 and 1,6 bar. Probably the knock problem was caused by a very small air leak in the rubber pipe that is connected from the inlet manifold and metal pipe where there is connected the ECU hose and the FPR hose.

Alessio

[Audi-Porsche Avant RS2]

Hello, I have seen that when the overboost turn on the boost pressure gauge oscillates near the value of the overboost, is this normal because is the N75 that work for keep the correct overboost pressure?

Thanks a lot!

Alessio

[Audi-Porsche Avant RS2]

Hello, someone can tell me if the fuel pump of the RS2 is the same of others Audi car? Because the Bosch database tell that is the same of others Audi cars. Thanks a lot!
Bye

Alessio