loss of power.....tried everything

[accy]

Hi guys
Audi a4 1.9tdi avf
Been having issues where the car losses boost/power....had the maf,map and n75 valve replaced with the originals. following faults always showed up


17932 (p1524)........fuel pump relay
18027 (p1619)........glow plug relay
17957 (p1549) boost pressure (n75)
17996 (p1588) engine mount solenoid

Couple of days a go had all the filters replaced and the car ran really smooth, but earlier today car ran like it had no boost but this time no eml light came on but stored the codes 17957 boost pressure (n75) and 17996 engine mount solenoid.....cleared the codes but still no boost........
later today the eml light came on with the codes 17932 fuel pump relay and 17996 engine mount solenoid again.....

Getting very annoying, could it be the variable vanes sticking?
actuator seems to be moving ok

[spartacus 68]

Similar thread on B5 forum. Owner replaced N75 valve but without success. Have you checked for any splits in vacuum hoses? Any smell of diesel. Not unusual for the flexible fuel return pipes next to the injectors to deteriorate. Audi sell the hoses that you can cut to length. Before going near the turbo, try a can of Forte diesel treatment straight into the fuel filter and drive hard in 2nd and 3rd gears. It'll smoke like a bonfire, but it will clear in 10 minutes. Replace fuel filter afterwards and top up with fresh diesel before starting engine.
http://www.vwaudiforum.co.uk/forum/showthread.php?127234-Which-one-is-the-N75-Valve-(110-AFN)

Also older thread here for AVF engine relating to faulty wiring: http://www.vwaudiforum.co.uk/forum/archive/index.php/t-101008.html?

[accy]

Forgot to mention when new original maf was put in, it ran great for a few days before loss/low boost returned.
Same after MAP sensor was replaced ran great for a couple of days and same again as with the N75 valve....
Why does it run great for a couple of days before the symptoms return even if the part replaced was not cause of the low/lost boost?

[nevo]

Firstly forget the engine mount solenoid its a common fault,secondly check the vac hoses to the n75 and the turbo actuator get a vac pump and simulate the action of the turbo actuator,thirdly check the maf connector for any corrosion,see what it runs like with it disconnected.

[accy]

thanks nevo.......will post the results
Still don't understand why the car runs great for a couple of days before the symptoms return even if the part replaced was not cause of the low/lost boost? ie maf,map, n75 valve

[accy]

Still constantly get 17932----fuel pump relay fault.
New genuine fuel pump relay replaced also wiring checked for corrosion/faulty but everything checks out ok.
Would anything else not being right trigger this fault code? ie turbo actuator/ variable vanes?

[nevo]

Can you hear the lift pump working? Try disconnecting the egr and plug the vac hose,are you still getting boost pressure fault codes.

[accy]

can't hear the lift pump working, yes still getting the boost pressure fault but not at the same time...
Get the fuel pump relay with the engine mount fault or the boost pressure fault with the engine mount fault

[Crasher]

They are all connected, including the engine mount, to the same circuit and it suggests to me a problem with the J317 terminal 30 voltage supply relay, possibly water damage (corrosion) in the under bonnet relay/ECU box.

[accy]

Thankyou
Will book it in with auto electrician

[accy]

The garage still closed all this week :(
No codes or limp mode for the last couple days, yet car runs with little or no boost

[Crasher]

My rule is "no codes, no power, new Air Mass Meter". Where did you buy your new AMM from?

[accy]

The maf was bought from tps

[Sinspeed]

Doesn't seem turbo related fault although it's obviously restricting turbo pressure flow.. Definitely looks like electrical failure maybe a corroded earth point or as suggested by Crasher water in fusebox/ecu etc.. Continuity test may be advised here on the relative circuit(s)


---
I am here: http://maps.google.com/maps?ll=51.479465,0.035704

[Crasher]

I am surprised it is not generating any codes if it is that bad and the AMM is new genuine. I had an 8E A4 like this in yesterday and we are having it back new week for a new AMM and to check the basic settings of the injectors as it has just had three new ones fitted as part of the recall, the only problem is this car is a 2L 16v TDI, not a 1.9.

[accy]

They are all connected, including the engine mount, to the same circuit and it suggests to me a problem with the J317 terminal 30 voltage supply relay, possibly water damage (corrosion) in the under bonnet relay/ECU box.

The above was all checked and all came out good, no corrosion or water damage in the ecu box or any of the connectors.
Still poor/no boost at times, think the actuator/variable vanes are sticking but no idea why these fault codes appear
As the car is remapped could the ECU throw up codes in the wrong fault?

[Crasher]

If it is definitely going into limp and not leaving codes I am stuck without seeing it.

[accy]

If it is definitely going into limp and not leaving codes I am stuck without seeing it.

Hi Crasher
Basically it drives poor, no boost or lack of boost no matter if the codes are there or not.
When the EML comes on the following codes appear

17932 (p1524)........fuel pump relay
18027 (p1619)........glow plug relay
17957 (p1549) boost pressure (n75)
17996 (p1588) engine mount solenoid

[nevo]

Can you get hold of a vacuum gauge,stick it on the turbo actuator vac pipe and rev it to 3000rpm see what you get.

[accy]

New twist to the saga
today while on the motorway car would not rev past 2000rpm no engine light came on.
Stored the code 17965/ charge pressure control positive deviation.
This points to actuator/variable vanes sticking.
Firstly wouldn't the engine light come on?
Secondly how is this connected to the fuel pump relay and n75 faults?....would freeing the actuator/variable vanes sort out the previous 4 faults?

[nevo]

It looks like its sticking,thats why I'm saying get back to basics,see if the turbo is being asked to boost,if no vac present follow it back to the next joint and test again,if there's a vac at the turbo see if its moving the arm.With regard to the fuel pump relay etc they could be a as others have said a electrical gremlin which is a nightmare to find.

[Crasher]

I think you should fit a new ECU relay (not fuel pump relay) and that 17965 code explains the limp mode (I knew it didn't add up) and 90% of the time means the turbo needs a rebuild.

[accy]

Thankyou

I'l get the vac test done on the turbo does seem like it needs rebuiling.
Crasher you wouldn't know the part number for the ecu relay? Would i be right in thinking its under the steering column near the fuel pump relay?
Doesn't the ecu relay have its own fault code?

[Crasher]

The main power relay for what is known as line 30 is effectively the ECU relay but powers various other devices such as the fuel pump relay, N75 valve and engine mount. It is in the water box under the windscreen at the side of the plenum chamber in with the ECU at position 3. The fuel pump relay is also in there at position 1 with the glow plug relay at 2 and relay 4 is for auto models only.

Position of relays

1) (1.1&1.2) Fuel pump relay J17 with 404 or 395 on top. 7M0 951 253 C or 4H0 951 253 C £13
2) Glow plug relay J52 with 202 on top. 8A0 951 253 £26.27
3) Terminal 30 voltage supply relay J317 with 219 on top. 443 951 253 AA £26.27
4) Automatic gearbox only


http://i222.photobucket.com/albums/dd20/Crasher1964/A48EAVFunderbonnetrelayplate.jpg

[accy]

Thanks again Crasher
Tells you how much i know, i thought the relay with 219 stamped on it and marked 443 951 253 AA was the electric cooling fan relay
Will keep you guys informed on how i get on

[accy]

Rang TPS gave them the part number 443 951 253 AA which the identified as Contact Closure Relay is this the same thing?

[Crasher]

I am pretty sure that I have got it right. The workshop information system is very clear that a 2002/3 8E A4 with an AVF engine has "3 - Terminal 30 voltage supply relay (J317)" but it does not give you the CGN (Control Group Number) that is printed on top of the relay it just gives you an SDC (Service Diagnose Code) of J317 and position number 3, plus location, the plenum chamber box. If you put the SDC in code J317 into the parts system, it only gives you one possibility “1J0 906 381 contact close relay, relay location/code no.: 3/429” which is for an ALZ 1.6 petrol engine…! Looking down the list of relays that can be fitted to the 2003 8E A4 in the plenum chamber box, the position numbers are shown as in the wiring diagram and at position 2 there are 5 different relays listed, 2 contact close relays, one of which is specifically for the ALZ engine, two glow plug relays specifically for different years of BKE engine and a time control unit for a CVT box on an unspecified vehicle. So, by a process of elimination that only leaves “443 951 253 AA contact close relay, relay location/code number.: 3/219” but for an unspecified vehicle or engine. It would make life so much easier if the CGN was on the wiring diagram and the SDC code didn’t tell me I needed something that is shown to be for another car. Assuming the wiring diagram is correct and without removing the relay at position 3 to get the part number off of it (which may have changed but I can cross reference old numbers) I can only assume I am correct. It's not that expensive anyway if I am wrong.

[accy]

Rang audi, they didn't have the ecu power relay in stock nor did tps.
The technician i took the car to didn't think the problem was with the ecu main relay, as he explained if it was then the car would atleast struggle to start.
He did change the relay 8z0 951 253 with 395 printed on top and i must say it runs alot better on a 50 mile run. ( no dreaded relay codes came back on).
As you mentioned the turbo needs rebuilding but unfortunately the turbo specialist has a lot on at the moment (back log) put back till at least a week.

[MR VAG]

how many miles has the car covered? sounds like a faulty turbo to me very very common on these engines and will boost for a while then not boost then go into limp mode and may even bring on the engine light. the actuator rod usually seems very hard when testing with a mityvac and the turbo usually sounds very noisey. would also remove the pipe coming off of the air box and check for play at the turbo impeller. expensive and depressing but like i said very common

[Crasher]

8Z0 951 253 changed to 7M0 951 253 C on the 01/05/2010 and is now 4H0 951 253 C and costs £13. It may now have the number 404 printed on top and is used at position 1 and is the fuel pump relay. This relay is supplied by the terminal 30 relay. If you were to ask your “mechanic” to study the current flow diagram he would see why I suspect the main supply relay but if he is not going to fit a new one I give up trying to help him/you. He obviously knows more than I do and so I will leave him to thrash around in the dark and drain your wallet with random ideas. I am not saying that I am right about relay 3 but following the wiring diagram, the symptoms make sense and all wag their finger at the relay. I am afraid I am going to have to pull out of this post and unsubscribe, PM me if you change the terminal 30 relay and it does not help, I will then join in again trying to help.

Steve

[accy]

Hi Crasher.....Firstly your help is always appreciated, I wouldn't have learnt where to begin without your help.
Like i said in my last post audi and tps did not have the ecu power relay in stock. If they did i would have got the technician to change it no matter what for my piece of mind.
The relay he did change 8z0 951 253 was a case of elimination as he had that relay. If it helps i keep if not then no charge. As soon as the sinister relay codes come back up the ecu power relay will be ordered and replaced.