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RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avant -
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Last edited by UrS4boy; 18 October 2012, 21:16.RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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Now now chaps.. Both of you have contributed beneficial information to this thread. But seriously, im not worth fighting over
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Further to your problems, I contacted one of the most knowledgible UrS people in North America (Steve E.) about your issue (I had pointed him to this thread) and he said:
"That RS2 has some interesting faults, but I highly doubt that it has a
defective MAP. Those NEVER go bad. Only ur quattros had MAP sensors
that failed. I would start by checking static timing VERY carefully.
If they had to move the belt to get rid of a CPS fault, that makes me
think the crank sprocket key may have sheared. BTST a few times with
very odd symptoms. Next I would check the vacuum line to the ECU."
BTST = Been there, seen that.
Me (UrS4boy) again - I think the key thing there is the MAP sensor fault is unlikely but it is more likely that you have a cam belt crank sprocket problem (broken key). Not easy to check, unfortunately.RS2'd 93 UrS4 5 spd sedan
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Yes, let's ignore the obvious code, which gets only set when MAPout = 5V in the assembly code.
The reason they had to move the belt is most likely because it was timed up wrong.
The RS2 has specific timing where you can set it one tooth advanced and one tooth retarded. But perhaps you have never timed up an RS2, since they are not that common in Canada.
I have also seen one of these sensors go bad.
Fact of the matter is, as long as that code is in there and it is impossible to erase, you will not get any boost. That code means that ECU sees a constant 5 volts for a certain duration of time on AN1 of the boost chip.
There is nothing else that will trigger this exact code.
So whether it is the MAP sensor, an op-amp or something else on the MAP signal going to the processor, this has nothing to do with any timing belt.
Further more, any timing fault will not give intermittent boost. There will be just no boost all the time.Comment
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Not sure how many RS2's this bloke has worked on in N America, but as we know on the Forum (a bunch of amateurs) the cam timing on the sprocket is incorrect if you line all the marks up on the RS2. Thats why it has to be set up a tooth out to avoid the Hall sensor fault and the associated odd performance. Why Audi did made the different pulley but did not amend the marks only they know. Its a common mistake as people assume the marks should all align.
Unfortunately all the OP can do is eliminate whatever he can based on the experience of others with whatever information we can throw at the problem.Comment
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One question: IF the cam belt crank pulley key has sheared and the pulley is moving a bit retarded/advanced when the engine is under power/off power, how would the ECU react to the fact that the G40 shutter window on the exhaust cam sprocket is moving position randomly? (That is what Steve E. is saying, nothing about RS2 cam timing per se).
Dmitri: Thanks for your clear answer above.
I wonder if RS2ZuidAfrika can find a "spare" RS2 ECU that he can borrow to confirm the MAP issue 110%.
Last edited by UrS4boy; 19 October 2012, 17:42.RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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It would probably have the same result as incorrectly set cam timing - the hall sensor fault.
As I read it he implied that the OP moved the cam timing to get rid of the fault. In reality, the OP reset the cam timing to the correct RS2 setting from the incorrect standard setting. So the vehicle is now set correctly and the Hall sensor fault has gone. If had been an ordinary ABY/ANN it might have been a valid point.
Its not very well documented if at all other than on here!
Now we have this other Map sensor code which was not apparent before! Such is the joy of working on cars!
As PRJ has said, you cannot ignore it especially if it is responsible for the limp home. So it needs to investigated. Bit of a coincidence it occured straight after correcting the other issue.Comment
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I find it odd as well that the code occurred after the other issue.
That is why I keep telling him to get it cleared and see if it reliably comes back all the time.
Maybe it's just a fluke and the reason for the limp home mode is different (MFTS and so on).
But also maybe the MAP sensor malfunctions at higher pressures.
As for the timing coming in and out of alignment - I am pretty sure just once is enough and the ECU will go limp mode until you restart it.
I think that is what happens also if you unplug the hall sensor and then plug it back in again. But I might be wrong on this, as I don't remember 100% for certain.Comment
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This is an interesting thread, one of the last times I drove my RS2 i noticed the turbo was not working and I am sure I had seen the (!) symbol flash up. Then a month later i drove and it was all fine again. Car has now been parked up since January since I have been out of the country. I thought it was down to lack of use. I am just away to get it through the MOT when i get back. I will have a better idea of things to look at if the problem comes back. I will let you know if i find anything.
Great information guys keep up the good work.Comment
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small update there chaps..
Decatted the car and the cats were utterly hideously blocked and disintegrated.
Boost problem persists, but she boosts all the way up in first and second, very strong indeed.
thereafter usual issue with no boost until she restarts. We are investigating the fuel pressure and the pressure coming into the MAP.
Feedback coming soonComment
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Which fault codes?
Fuel pressure and so on will not put it in limp mode.Comment
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