1.9 tdi in limp mode, power loss

[leeg1187]

hi, i have an audi a4 b5 1.9 tdi (v reg) the vehicle was in limp mode when i bought it hence the cheap price, i have been following a few threads on this site and others in an attempt to diagnose the problem, so far i am unsuccessful in finding a thread with the exact same symptoms although many are similar up to a point for example a thread started by Djjoker (identifying power loss audi 1.9 tdi) is the closest.

so my cars symptoms are as follows
-limp mode.. (constantly! no noticable change in power after switch off/on ign, or up/down hills, weather, moisture, hot or cold, ect),
-also car has no boost as this is my first experience with one of these motors (1.9 tdi) i can not hear any sound coming from the turbo i dont know whether its normal or not??

things i have already done are
-checked the MAF sensor, took it off and run the car, no noticeable change, cleaned the sensor plate and wires with electricial contact cleaner spray anyway. no change.

im stuck on what to look at next,
with my symptoms can someone who knows more than me please point me in the right direction
thanks.. lee

[Dan J]

You should be able to hear the turbo spool up then level out, the turbo vain could be sticking which is common on tdi's with all the crap going through them, inlet manifold could be blocked with gunk, also egr valve could be sticking, check boost pipes, all breather pipes including the one going back to the ecu. Get it on vagcom to see what codes it's throwing up which should give you an idea of what's going on.

when I bought mine (also my first Audi tdi) it had black crap all through the breather system, manifold was so thick with it I'm surprised it ran at all, egr valve was blocked, turbo vain was sticking causing it to cut the boost at around 3000rpm and go into limp mode, now all cleaned out (not a five min job trust me ) breather pipes replaced, turbo vain working properly again, it runs like a new car and has plenty of grunt.

my advise would be check the above elements, to me your turbo vain sounds like its stuck shut hence not hearing it spool up, blocked manifold egr valve etc could also throw it into limp mode, hopefully it's a case of cleaning/replacing pipes where needed and not anything more serious,

hope this helps, just trying to give you somewhere to start that's not going to cost you an arm and a leg if its not needed.

[Doctle Odd]

First scan with VCDS it could be the boost solenoid which is a quick easy fix

[leeg1187]

hi again
thanks dan i will have a look at the pipes first as some dont look to clever.. i am waiting for the lead to do the vagcom for the fault codes also thanks Doctle Odd for the link really helpful page! got it bookmarked thanks..
one thing i forgot to mention on the first post was, the thing bolted to the top of the turbo with vacume pipes going in to it (actuator i think), i was reading a different thread with similar symptoms to mine and someone said to feel underneath the actuator whilst someone turns over the car and it should move in and out at least once there is no movement with mine at all i waited for at least 60secs probably more, nothing, it feels like it hasnt moved for a while lots of crap on it that feels like its been there for while but i cant say for certain due to lack of experience it definitely had no movement when i checked though i dont know if this info helps in finding the problem??
thanks again il let you know when i know more..
lee

[leeg1187]

also just thinking about it i have quite an annoying rattle when the car is idling i thought it might be a heat sheild but after getting under the car i now think it is contained in the exhaust its coming from roughly underneath the driver pedals that area as best as i can work out anyway, now that you mentioned a little about how the system works eg takes some exhaust gas back through that wouldnt have anything to do with limp mode would it?

[Dan J]

It's proberly the rough idle that's causing the rattling due to the turbo vain not being free(your cat box and down pipe run down just in front of the pedals.
I had this on mine and it stopped once I'd cleared the whole system out, if there's no movement in your actuator shaft then your vain is or could be stuck, if there's loads of gunk round the actuator shaft area give it a good clean so you can eliminate that being the cause of the problem though it still may not move once you've cleaned it all which then means your vains are definatly stuck.
it should move up and down freely, there should be a little resistance there when you push it up and down but not so much that you have to really really push it to get it move.

dodgy boost pipes and old knackered breather pipes don't help either, I ended up replacing all of mine and the difference it made was worth it, even a leaking boost pipe can throw it into limp mode, happened to me on one occasion but the pipe didn't look to great to begin with so not surprised it blew a hole in it.

Not sure if the egr valve would really cause it to go into limp mode because all it does is send some hot gasses back through the inlet manifold, though this can cause the inlet to get very clogged up with crap as mine did which causes your fuel consumption to go up because its not breathing very well, rough idling, loss of power,

from your description I'm putting my money on your turbo vain and actuator sticking, could be wrong but my gut feeling is telling me that's what it could be,

[Doctle Odd]

The car is 1997? I'm not great on UK reg plates but that model would have the AFN, AHU or AHH engine none of them have vanes on the turbo. Start with the vacuum pipes check for splits and loose connections, these are very cheap so it's probably best to change the lot. Next check the boost pipes from to and from the intercooler and turbo, replace any burst/split ones. The turbo actuator should move by hand or vacuum easily enough if not take it off and clean it. Get rid of the EGR with this VW EGR BLANKING PLATE 1.2 1.4 1.9 2.0 2.5TDI ONE LUPO BORA POLO GOLF T4 T5 CADDY | eBay or a home made one. The EGR does very little on these cars. Finally check if the ECU vacuum hose and if its in good condition and securely attached at both ends. This should keep you ticking over until your cable arrives

[leeg1187]

hi thanks again dan/ doctle odd, i have just found and looked through the user manual and log book ect, the date of manufacture was 1999, i thought it was an earlier model myself but i can not find any info on engine type, AFN, AHU or AHH?? i dont know which. i believe the pipes/ hoses do require some tlc but im finding it very difficult to identify any issues due to a messy engine bay alto the vehicle has been maintained well with regards to regular servicing, belts ect, the engine bay is a pig sty i have been looking on youtube and have found a lot of mixed opinions on whether its ok to use a small not very powerful pressure washer in the engine bay i really dont want to damage anything especially electrical! but that being said it is a real mess! this pressure washer is a small home washer with limited temp output and pressure, i have no trouble using it on the paint work for example.. some educated advice on the subject would be greatly appreciated..
ps i am very impressed and greatful for your advice/assistance with this as avoiding expensive repair bills for me right now is of paramount importance!!
so thanks again :-)
lee

[Doctle Odd]

There is a sticker on the cam belt cover or in the spare wheel well with engine code on it. A main dealer will give you the engine code too. As long as all the intake hoses are tight a little hot water will do no harm. Get some Gunk or a spray engine cleaner from Halfords or similar it will loosen the crud on the engine. Usually it's the rocker cover gasket that either fails or isn't on properly but teats under a tenner. I wouldn't be too worried about the electrical s as long as you don't saturate them but diesel engines hate water so make sure all breather/turbo pipes are secure with no splits. Mrs Odd bought a little steam cleaner in Argos that I commandeered several years ago

[leeg1187]

ok thanks i shall go on a sticker hunt right now and get back to you :-)