HELP! Mechanical boost only - mostly!?

[madpugger]

Hi guys, need some help!

The black S2 I bought from Pix, with a 3071 in it, has developed a fault and I am not sure what it is.

Symptoms are;

Mostly mechanical boost only (~0.5 bar according to gauge)
Will sometimes boost above this in high gears until around 3.5 krpm

Faults found so far but unsure of how long they were up...

Intake pressure faulty (I cleared it and it has not come back up)
ECU memory error intermittant (cleared but not checked again yet)

The water temp gauge also stopped working and I found the two wires on the rear sender of the water manifold had dropped off, it also runs VERY cold (its freeeeeezing in the cabin!) but I suspect this to be thermostat and also very much unrelated to no boost!)

I checked the N75 by removing it and putting power to it, it works fine.

What next?

Thanks

[prj]

1. Post the proper error codes, not "what you think they sounded like".
2. If you are getting memory errors, then either whoever tuned that car does not know what he is doing or your ECU has damage.

Oh and... do a boost leak test.

[madpugger]

1. Post the proper error codes, not "what you think they sounded like".
2. If you are getting memory errors, then either whoever tuned that car does not know what he is doing or your ECU has damage.

Oh and... do a boost leak test.

Yeah I know, sorry, I forgot to save the codes

I also forgot to post that I suspect the memory error is due to the battery going dead after a fortnight.

[prj]

No, I don't think you can have an internal memory error due to the battery going dead...
If it went totally dead, you would not have any codes at all.

So... do a leak test and get proper codes.

[madpugger]

No, I don't think you can have an internal memory error due to the battery going bad...

OK well I will pull the codes again.

[madpugger]

Monday,15,November,2010,11:24:45:45226
VCDS Version: Release 10.6.1
Data version: 20100831



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8C - Audi 80/S2 B4
Scan: 01 02 03 08 15 25

-------------------------------------------------------------------------------
Address 01: Engine Labels: 895-907-551.lbl
Part No: 895 907 551 A
Component: 2,2l R5 MOTR.RHV HS D02
VCID: 224F176184BD

5 Faults Found:
65535 - Internal Control Module Memory Error
00-00 - -
00515 - Camshaft Position (Hall) Sensor (G40)
01-10 - Signal Shorted to Plus - Intermittent
00519 - Intake Manifold Pressure Sensor (G71)
07-00 - Signal too Low
00553 - Mass Air Flow Sensor (G70)
07-10 - Signal too Low - Intermittent
00513 - Engine Speed Sensor (G28)
03-00 - No Signal
Readiness: N/A

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4A0-907-379.lbl
Part No: 4A0 907 379
Component: Bremsen-Elektronik
Shop #: BB 37175
VCID: E8DBC549A201

No fault code found.

End ---------------------------------------------------------------------


MAF you can ignore, that was me unplugging it while running.

Hall sensor is a new one. I know It has an affect on boost above 4k rpm on WOT but it also affects starting which is not an issue either, plus it does not get boost off of WOT either. One to look at for me though.

G28, engine not running.

[prj]

Did you always have the internal memory error?
If not, something is really wrong with your ECU... maybe a cold joint?

[madpugger]

It was not there the first time I looked with a launch X431.

It was on Sat night and I cleared it, it is again now, worrying

I am told MRC did the work so maybe I will have to send the ECU back to them. I hope they can bench test it as I live 700 miles away

[Audi-Porsche Avant RS2]

G28 error is normal when engine not run, when run must disappear, G71 is pressure sensor in the ecu, so the best thing for me is test the car with another ecu with same chip and correct map in the ecu, also if is not easy I think do this test.
Alessio

[prj]

Well, 65535 code is a checksum IIRC in the fuel chip (might also be the boost chip) not matching.
Those chips don't go bad by themselves, so if it wasn't there and is there now, it indicates an electrical problem in the ECU.
What supports the idea, is that the ECU reports the MAP sensor reports signal being too low at the same time.

You can try opening the ECU and seeing if something is blatantly wrong. Maybe the MAP sensor was soldered badly and a wire has come off, or something similar. Though, if you are not decent with the soldering iron, it's better to leave that up to someone who is.

As Alessio said, best would be to get another ECU with the same MAP sensor and R201 resistor and swap the chips... This is exactly why I have two ECU's...

[madpugger]

I have another S2 but it still has the aby map sensor. Also it is an immob version

I am trying to get hold on MRC to see if he would rather I sent it to him to look at. I am pretty good at soldering and have a load of soldering kit, but i would rather they broke/fixed it themselves!

Anyone got a vems map for a 3071 in the meantime? Thats a joke, cant be arsed fitting it to that car!

[prj]

I will PM you about how to test.

[madpugger]

Thanks for the PM

[madpugger]

Ok so how the heck does the ecu split?! I have it down to the pcbs but can't get it to hinge!

[prj]

Hehehehe....

http://www.youtube.com/watch?v=CBX22emnv0k&fmt=22