s4 problems

[ljames]

hey not sure if anyone can help.my mate has got a s4,and we are having a few problems with it.I have a full legal vag com and plugged it in and getting these fault codes..
17861 exhaust gas temp sensor 1,open or short
17865 exhaust gas temp sensor 2 open or short
17965 charge pressure control,positive deviation,i know this means over boost.

now the car runs fine when idleing but under accleration,it holds back and pushes and shoves,like theres no fuel.I am no expert on the vag com,and dont know what figures i should be getting via boost pressure etc.any help from any one would be really appriciated,thanks leighton

 

[aragorn]

I'd be looking for boost leaks, and it looks like you need a pair of EGT sensors.

 

[stapo69]

I concur! Boost leak, commonly split throttle body boot, but check all your hoses anyway, and a new pair of audi's finest most expensive EGT sensors, it'll be like driving a new car with them sorted!

 

[S4twiggy]

leighton i had the same problems with mine a month ago, mine were lamba sensors an like you said it was ok idle but when accelerated felt like no fuel was getting through, got a new lamba sensor on and it needed a new dump valve and after that she is fine so id defo get them EGT sensors on it, not sure bout the other problem though.

where bouts you from in south wales mate

 

[ljames]

thanks for the reply guys! iam the leightons mate with the s4. i ve done a lot of reserch on this problem, and it looks like new EGT sensors is the answer!. but dont know where to get them from?? any ideas??
P.S. we are from bridgend.

 

[Blue_Thunder]

I'd be checking your MAF as well to be honest. If that's gone, it can knacker your EGT sensors because the car runs too lean.

Disconnect your MAF, clear the codes on Vagcom and go for a drive to see if it's running smoother. After a decent drive, check for codes again and post up what you get.

 

[ljames]

couple of days ago i notised that my car is loosing oil, and also notised oil splatered all over the front plastic cover that sits in within the Y pipe. so i disided to inspect it. took the cover off and notised that the cover is fuul of oil on the inside. there are two large plastic pipes that fit into a rubber Y pice with an electronic connector on top of it. well there is a large split in that rubber, so i think that is my problem..... i started the car and put my hand over the split and i could feel the pressure escaping from it.....iam going to get it sorted asap and let u know what happends next!!

 

[aragorn]

thats the throtle body boot, and yes, that will cause big problems if its split.

Take it easy when driving around, or you can kill the turbos

 

[Blue_Thunder]

Unplug the N75 (brown connector near the back of the Y-pipe) so your turbos don't try to make boost. You will destroy your K03's boosting with a split TBB.

The best option (although the priciest) is the APR Bi-pipe, a metal replacement for the TBB. Samco and Autobahn88 (eBay) TBB's usually need trimming down a bit otherwise you can't get the front engine cover back on.

ps. Think you might be dreaming 'feeling the pressure escape' from it though. At idle the TBB is under vacuum. You only get boost when the engine is under load.

 

[ljames]

cool.....! thanks for advise! i dont actually rev it over 2500rpm, so it should be ok! i ve odered new tbb from audi, cost 11 quid. didnt know about the metal replasements tho, but sounds like a good idea! and i forgot to say that when i put my hand over the split tbb, i did feel the presure escape, cos i give a good rev! infact it sounded like a dump valve!!! the new tbb is coming wendsday, so i ll keep u updated! aprishiate yr help and advice!

 

[jonnya]

Sounds like you still need EGT sensors though. Suck it up because you won't see much
change out of 300 quid for the pair (and they can be a total ******* to bit).

 

[ljames]

hi every one again! i got my new TBB today and fited it! and the car is like new again!!!! well happy! that was probably the cheapest repair i have ever carried out on this car!! thanks to everyone for the support and advice!

 

[Fraser]

you should get the car pressure tested and also sort the following parts

EGTs as mentioned - don't ignore these - more expensive
N75 - cheap @ £35
DVs - cheap @ £40 for the pair
MAF if needed - not so cheap @ around £100 exchange
F-hose delete by someone who knows what they are doing

it sounds like you are ignoring the EGTs after throwing on the new TBB. Don't ignore these common failure parts as we will soon see you again with some blown turbos!