RS2 rough idle and stupid 00561 code

[GT500]

At least we can do math and understand how fuel pressure regulators work.

Fuel rail pressure = Rated FPR pressure plus boost (or minus vacuum).

At least we have social skills. Being able to read does help.
Never mentioned what you spouted.
Contradicting someone's comment with such a bad attitude face to face over here would see most folk trying hospital food. Why should a forum be different?
Odd.

[UrS4boy]

At least we have social skills. Being able to read does help.
Never mentioned what you spouted. Contradicting someone's comment with such a bad attitude face to face over here would see most folk trying hospital food. Why should a forum be different? Odd.

Dude. Chill out.

Threats of physical violence over a maths correction? Really? Wow.

[GT500]

Dude. Chill out.

Threats of physical violence over a maths correction? Really? Wow.

Just go back to school and learn to read and communicate and it'll stop you missing points and winding yourself up.
No maths correction has happened or been needed. My original info was incorrect by .2 of a bar. No equation needed. Really?? Can you see that? I can't spell it out any clearer.

No threats either have been made. Only an observation on how badly worded retorts in life can alight short tempers. Someone trying to help another then someone else buts in with poorly chosen vocabulary in my experience tends not to get chance to do similar a second time.

I won't be editing my posts. I don't need to.

[UrS4boy]

Just go back to school and learn to read and communicate and it'll stop you missing points and winding yourself up.

Mine being an rs2 it should be 4 bar but I seem to remember s2 should be 4.2 on idle. It should on the side of the regulator.

I read just fine thanks. The problem is the info that you remember is not out 0.2 Bar, it is out more and/or you don't understand how the FPR works. They are designed to maintain the exact same pressure across the fuel injector a both idle, normal running and boost, i.e. 3.8 Bar for an RS2 and 4.0 Bar for an ABY or AAN.

Assuming a nice warm engine with 16 inches of Mercury vacuum (about 0.541 Bar vacuum), an RS2 with a 3.8 Bar FPR will idle with about 3.26 (= 3.8-0.54) Bar in the fuel rail. Likewise a warm AAN or ABY with a 4 Bar FPR and 16" Hg (0.541 Bar) vacuum at idle will have about 3.46 Bar in the fuel rail at idle. Under boost, e.g. 1.9 bar, the fuel rail would have 5.7 Bar in an RS2 and 5.9 Bar in an AAN. Any less and you will lean out and there will be issues.

[Error404]

I think Rob knows how a FPR works

[UrS4boy]

I think Rob knows how a FPR works

If you say so. I saw no evidence of that via his comments regarding idle fuel rail pressures.

[mike74]

Not meaning to hijack here but, how exactly does the ECU know how or when to throw up a 561 code? I understand it knows how much air (& therefore fuel) has been ingested via the MAF but after this, what tells the ECU something is amiss?

[Thecrispynoodle]

Not meaning to hijack here but, how exactly does the ECU know how or when to throw up a 561 code? I understand it knows how much air (& therefore fuel) has been ingested via the MAF but after this, what tells the ECU something is amiss?

O2 sensor is used over several usage cycles. It is not a dynamic adjustment in all cases. 561 means for the amount of measured air the amount of correction in fuel being added to achieve the desired o2 reading is outside of the physically possible compensation ranges. Bad MAF and/or connector, bad FPR, bad fuel pump, air leaks post MAF will all cause this.

[mike74]

O2 sensor is used over several usage cycles. It is not a dynamic adjustment in all cases. 561 means for the amount of measured air the amount of correction in fuel being added to achieve the desired o2 reading is outside of the physically possible compensation ranges. Bad MAF and/or connector, bad FPR, bad fuel pump, air leaks post MAF will all cause this.

Cheers buddy
So if the O2 sensor is duff or even a bit lazy it could cause this code? (final thread intrusion, promise!)

[Thecrispynoodle]

Cheers buddy
So if the O2 sensor is duff or even a bit lazy it could cause this code? (final thread intrusion, promise!)

A good working O2 sensor is a pre-requisite, but don't be surprised if replacing it doesn't fix the problem because the root cause was elsewhere and possibly due to multiple reasons. It's worth checking your MAF screens are still in place removing these will throw the MAF readings out particularly at idle

[BosnianS2]

That was little rough reagarding fuel pressure discussion but however ist seems to point out that I have problem with my fuel pressure also. Like I said in earlier post, i measured to be 4 bar at idle ( vacuum connected to FPR), so that can not be right based on info here.

Even though i use cheap gauge but i dont think it can be that wrong. First I will check if my FPR is correct one and then replace it if it is. Maybe it took a dump over the years of use

Latest info regarding my issue is that after replacing the O2 Sensor, code has not come back yet, however I manged to break the hose between trhottle body and this black metal pipe, so I am replacing it with used one today cause the are NLA from Audi.

I think its time for some silicone hoses.

[UrS4boy]

Intermittent Fuel Pressure Regulator Diaphragm Leak

That was little rough reagarding fuel pressure discussion but however ist seems to point out that I have problem with my fuel pressure also. Like I said in earlier post, i measured to be 4 bar at idle ( vacuum connected to FPR), so that can not be right based on info here.

For "fun" watch this video (in the link). Skip to the 3:00 mark if you want. The leak doesn't show up until about 3:58.

https://www.youtube.com/watch?v=AKtR_yF7bi8

[DEREKCO]

Rough idle

Hey guys there is enough crap dialogue going on in the world without us sounding off ,Dave is a good guy so get off his back if you use your brains and the forum you will find that Dave has posted a vast amount of information for YOUR benefit and mine Dave doesn't need me to defend his words but I will LAY OFF AND GROW UP we are grown men ,not squabbling children .ps hello Dave keep the info coming

[UrS4boy]

Dave? Dave's not here man.

https://www.youtube.com/watch?v=N-Wk_0A0kT8

I was just doing my regular morning cruise through the S2 forum looking to see if I could help and found your post Derek. Thanks.

[mike74]

Lol, have to love the cheech n chong ��