Loss Of Power A4

[bee144g]

can i jion your club. I have an Audi a4 1.9 tdi avant with exactly the same probs. I have had the car 3 years now from 87,000 it has now done 98 and has had this problem from around a month after i bought it. It when t back under warrenty they replaced the e c u the m a f, but i still have the problem, Its only recently i have started to play with other things, Im a vehicle tech i have friends that work for audi and know one seems to know what it is. the car used to go for weeks without the prob then suddenlly when you need a bit of power its like the turbo shuts down, but now it seems to be getting more and more frequent,, Any sugestions

[Donald M]

Hi there,

Just to let you know what I did. There is a hose from the top of the EGR valve to some ecu behind the radiator. It had come off and all I did was push it back on. Car works fine now. The light is still flashing though.

[bee144g]

Originally Posted by Donald M

Hi there,

Just to let you know what I did. There is a hose from the top of the EGR valve to some ecu behind the radiator. It had come off and all I did was push it back on. Car works fine now. The light is still flashing though.

it may be something to do with that switch but all the hoses are intact and in place the electrical conector is in place but i still have the problem

[bee144g]

also i dont have any warning lights on all i have is a sudden loss of power. when this happens i can turn off the ignition and back on and it clears itself till the next time wich could be 5 mins or longer however it is becoming more and more frequent

[912uk]

Sounds 100% what I had, I have just bought the car..and it was gutless. I hated it..

loss of power eg lorries over take you going up a hill!!!!!!

ok I worked out it was the Mass Air Flow meter...

cost £30 from G&S and I replaced the air filter also...... now it goes like a bat out of hell!!!!!!

the senser is a single wire stand and it corrodes and then breaks once it breaks the it creates a short and the computer puts the car in safe mode...



MODS!!!!!!!

this loss of power and the mass air meter, should be made a sticky for DTi owners..it's an easy fix and can be done by almost any one who can hold a screwdriver..

[ini]

The 'overboost' problem is very common on VE engine direct injection TDI's.

The symptom is the boost cutting out under load, up hills or at motorway speeds, generally in third gear or higher at around 3000rpm. If you cycle the ignition it resets it.

There are a few main causes for this problem:

The main suspect in 90% of these cases is the 'hot film' Mass Airflow Meter, especially Bosch Maf's which degrade or fail a lot earlier than the Pierburg type.
Running the engine with the MAF disconnected will cause the ECU to use default values, if the car runs better your MAF is totaly knackered, but this method will not allways diagnose a worn or failing MAF.
First try cleaning the element with a suitable spray solvent, and disconnecting and reconnecting the connector several times.

The EGR valve could be gummed up and not closing properly, causing hot oxygen poor exhaust gas to interfere with your fuel/air ratio. If your EGR valve is on its way out, or in need of cleaning it may start to make a 'squawking noise' like a goose. Solved by cleaning or replacing your EGR valve.

If you have a 90bhp model the waste-gate may be fouled or sticking.

If you have a 110 the VNT actuator rod & lever may need a bit of WD40 spraying on it, or the VNT vanes may be sticking in the 'full boost' position, this can sometimes be remedied by aggresive use of the accelerator, or dismantle the turbo and clean the VNT mechanism.

Inlet Manifold fouled, due to the EGR system the inlet manifold is prone to developing a thick layer of sooty crud, which can seriously reduce the volume and airflow of the manifold, this layer can become so thick that it alters the reported manifold pressure.
Remove manifold and clean.

Boost Leak or Boost control leak, check all boost side pipes and hoses especially to and from the intercooler, hose from n75 to the vnt actuator or wastegate, and the small tube to the MAP (on AFN engine with pressure sensor in the ECU check or replace this tube, it is prone to leaks and as mentioned above it is badly designed and traps liquid.)
Feel all the braided rubber hoses where they join other tubes or touch anything, as the rubber can wear away inside leaving the external braid looking intact.
It is recommended to just replace all the small tubes in the control system rather than try and find a minute leak, they cost next to nothing.

Timing can cause the same overboost symptoms. If you are overdue for a timing belt change or sometimes even if you have recently had one, your timing may be too far retarded, causing under-fueling.
A worn/dodgy fuel temp sensor can also cause timing to fluctuate.
If your overboost problem goes away for a few weeks after towing, or if a tuning box stops it, your problem could well be retarded timing.
Use VAG-COM/VAGSCOPE etc to check.
Also if you have your radio code, try disconnecting your battery for 15mins and go for a spin and see if there is any change.

Chipped cars/tuning boxes can also interfere with engine management causing the same kind of problems.

[paddycars]

Hi
I am yet another new member to the dodgy 1.9 tdi turbo club. It first happened about 10 months ago (when I first bought the car) but after a couple of weeks sorted itself out, so with the old adage of if it aint broke dont fix it I learned to drive with fingers crossed. Well its broke again and a diesel fitter mate of mine has suggested the solonoid as well so will be having a go with it at weekend. cheers. its nice to know i am not alone.

[a8 tech]

Turbo actuator arm sticking,catalyst blocked.Also woodruff key on crank wears and causes pump timing to fluctuate when accelerating,runs ok at idle.When fault occurs(limp home mode) turn ignition off and restart,if power restored for short time look at the turbo also the intake manifolds block up at high mileage.Could go on but iam boring myself and my wife has told me to goto bed.Regards Jon

[Cybahawk]

HI All, played around after sending my car in to the shop, it got worst when they worked on it, they told me it was the airflow meter, and that they cleaned it... unn thing is i don't think the guy knew what he was cleaning or where it is, cause the airbox was untouched so he could not have cleaned it... anyway I asked what would happen if i disconnect the AFM he said it won't work... well tried t and the car runs perfect.... no errors nothing.... all i did was unplug the connector and back to the old performance, what a pleasure... so guess it is the AFM, and ill replace it, but for the meantime it works with it disconnected so lets see... just lift the cover over the airbox, pull out the seal and unplug the AFM leave the plug in the airbox and close seal... simple as that, the responce was instant, tested a few times and that was the problem....

Hope this works for a few of you guys too.
All the Best.

[bigcrags]

I'm a member of this club too at 120,000 miles. First thing I did was change the MAF sensor. Still the same.
All my local garages said I should take it to the Audi dealer. I did this and they hooked it up to the computer. Apparently a faulty fuel cut-off solenoid was the diagnosis. Paid £142 to get that changed. Didn't make a bit of difference.
They also suggested the intake manifold was showing an intermittant fault. I know cleaning it out is a reasonably involved job so I might go to a local mechanic to do it rather than paying dealer prices.
I've just ordered an interface cable and downloaded vag-com so that I can check for faults showing after each thing that I do. Hoping it will give me a clearer picture of what's going on.