RS2 No boost after 30seconds of startup

[UrS4boy]

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.

[RS2ZuidAfrika]

Now now chaps.. Both of you have contributed beneficial information to this thread. But seriously, im not worth fighting over

[UrS4boy]

And you really really hate being wrong.

I can accept being wrong. You can't accept anybody being even close to being right. Your ego will just not allow that. Poor you.

[prj]

Not random. Directed entirely and purposely at the level of modesty and humility you present on these topics. No one is as good as you.

Apparently.

And you really really hate being wrong.

[UrS4boy]

So wait, let me get this straight. You say that you need a PCB for installation, I tell you that I have installed 120 of them without doing this, then you just start spamming random ****.

Not random. Directed entirely and purposely at the level of modesty and humility you present on these topics. No one is as good as you.

Apparently.

[prj]

You are truly a god amongst men.

So wait, let me get this straight. You say that you need a PCB for installation, I tell you that I have installed 120 of them without doing this, then you just start spamming random ****.

And I thought I was speaking to a grown man

[UrS4boy]

...You just need this sensor, a soldering iron, some wires, a single cable tie and some skill.

You are truly a god amongst men.

[prj]

Ugly? What does that matter? Who sees it?

One of the advantages of the VMAP was that it could be adjusted. Some versions required changing jumper positions to do this. The version that I got was the one that I could adjust it from 3.0 Bar down to 2.7 Bar and up to 3.1 Bar in 0.1 Bar steps by turning the ignition to on and toe tapping the throttle. Very clever in my opinion. That said I only had to do that once when I could only get an inferior octane fuel. Nice to have. Only cost $40 more at the time.

Yeah, really good to fool the ECU by giving it wrong signals without altering the map.
Maybe you think putting a potentiometer on the MAF signal is a great idea too???

Manufacturer: Freescale Semiconductor

But it still needs a PCB for installation.

And your point is? The voltage curve has below 1% deviation from Bosch curve in the usable range.
I also don't see what you mean by "needs a PCB for installation". I have installed about 120 of these without any PCB.

You just need this sensor, a soldering iron, some wires, a single cable tie and some skill.

[UrS4boy]

No need for big ugly VMAP things which do not match the bosch specs of voltage output and give signal too low and signal too high codes in some cases. At least that was the case with the older one, I have not tried Marc's or 034's solutions.

Ugly? What does that matter? Who sees it?

One of the advantages of the VMAP was that it could be adjusted. Some versions required changing jumper positions to do this. The version that I got was the one that I could adjust it from 3.0 Bar down to 2.7 Bar and up to 3.1 Bar in 0.1 Bar steps by turning the ignition to on and toe tapping the throttle. Very clever in my opinion. That said I only had to do that once when I could only get an inferior octane fuel. Nice to have. Only cost $40 more at the time.

[UrS4boy]

This part will perform exactly the same function for 10$:
http://www2.mouser.com/ProductDetail...VB13CCYzmk53xJ

Manufacturer: Freescale Semiconductor

But it still needs a PCB for installation.

[prj]

More G71 nfo:

http://forums.quattroworld.com/s4s6/msgs/20417.phtml

VMAP from 034 for about US$105

http://www.034motorsport.com/034efi-engine-management-engine-management-sensors-034efi-varimap-switchable-25-bar-map-sensor-p-521.html

EFI Express's US$80 offering:
http://www.efiexpress.com/catalog/pr...products_id=82

This part will perform exactly the same function for 10$:

http://www2.mouser.com/ProductDetail/Freescale-Semiconductor/MPXH6300AC6T1/?qs=sGAEpiMZZMt7FrWooXVB13CCYzmk53xJ

No need for big ugly VMAP things which do not match the bosch specs of voltage output and give signal too low and signal too high codes in some cases.
At least that was the case with the older one, I have not tried Marc's or 034's solutions.

[UrS4boy]

G71 Manifold Absolute Pressure (MAP) sensor information

...Last i will atempt the Map sensor , i just havent heard of a map sensor go south before. I prob have my original map sensor (s2) somewher , but rs2 has a 3 bar sensor ? Does the rs2 have a fuel pressure sensor ?

The RS2 doesn't have a fuel pressure sensor (nor does an S2 or UrS4/S6). However, the RS2 does have a 300 kPa (3 Bar) MAP sensor, compared to the ABY S2s's and UrS4/S6s 250 kPa (2.5 Bar) sensor. OE Bosch sensors don't seem to fail very often. I have been around these cars (20V Turbo I-5s) since 1998, on various UrS forums and honestly do not recall anyone posting about a failure. That said, it is common to upgrade the 2.5 Bar MAP sensors to 3.0 Bar when going to say MTM Stage 1+ chip levels (280 hp) and above. Definitely required when adding larger turbos (e.g. RS2 K24-7200) and injectors.

The G71 MAP sensor is soldered to the bottom ECU PCB. As such, it is not normally an owner serviceable part. That said, lots of people know how to properly desolder chips from the PCB. These same people could certainly remove a faulty MAP sensor and replace it with a new/know-to-be-good 3.0 Bar Bosch or a VMAP or the $80 one from EFI Express.

More G71 nfo:

http://forums.quattroworld.com/s4s6/msgs/20417.phtml

VMAP from 034 for about US$105

http://www.034motorsport.com/034efi-engine-management-engine-management-sensors-034efi-varimap-switchable-25-bar-map-sensor-p-521.html

EFI Express's US$80 offering:
http://www.efiexpress.com/catalog/pr...products_id=82

[prj]

prj any chance that the performance issue it's due to a faulty knock sensor?

Then there would be a code for it.

About the MFTS I had run before with the plug disconnected (bad MFTS was triggering off my A/C in august...) and again I can assure there's absolutely no affection on the car performance.

If it is disconnected, there is no effect yes. If the MFTS is bad and it is shorted together, THEN there is an effect on performance.
The thermal switch is open in normal operation and closed during high temperature, and they usually fail closed.

But in this case there is a clear fault code. What's the point of coming up with imaginary reasons, if there is a MAP sensor - signal too high code in the ECU?
That code will ALWAYS and INSTANTLY trigger limp mode with no boost. So if that code is there and it is impossible to erase, you have found your problem.

[veneto rs2]

My two pennies....

prj any chance that the performance issue it's due to a faulty knock sensor?
The knock sensors are in deed triggering the ignition point if I remember well ?

About the brake warning light in all my 15 years Ihad several times for different reasons the red brake light lit on the dashboard but this ha never had any influence on the boost or performance in general.

About the MFTS I had run before with the plug disconnected (bad MFTS was triggering off my A/C in august...) and again I can assure there's absolutely no affection on the car performance.


Stefano

[prj]

Clear the faults, does the MAP sensor fault come back all the time?
And "attempt the MAP sensor", this lives inside the ECU and it is not user serviceable.