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View Full Version : 1996 a4 tdi loss of power. help please



marty67
09-02-2007, 07:09 PM
I have recently purchased an Audi A4 1.9 tdi which I am having a recurring problem with. Under certain conditions i.e. 60mph in 3rd, 70mph in 4th, and around 80mph in 5th, the car loses power and goes into what I can only describe as limp mode, (very poor acceleration in ALL gears). However when i briefly turn the engine off and the back on again, all power is restored untill I reach these speeds again. If I gently ease the speed up and change gear early I can build up speed but when I "floor it" I lose all the power again. There is no sign of any smoke when this occurs. I have changed the MAF sensor and all breather pipes for new ones and the fault still occurs. I also found that the piston inside the exhaust return was solid, but after freeing it the problem is still there. I have used VAG COM free version and the code is 00575 inlet manifold pressure - difference intermittent. I have also taken block readings when the car is idling, but don't really know what they are all about. Any assistance would be GREATLY appreciated. p.s. I live in Falkirk.

marty67
09-02-2007, 07:18 PM
I've also changed the rocker head gasket bacuase this had a slight leak, but I don' think that this is in any way connected.

ad4pm
09-02-2007, 07:54 PM
I had a similar problem with my '97 TDI, and fortunately it was under a warranty from a used car dealer, has I ended up with a new turbo fitted which did the trick!

seraph
09-02-2007, 07:57 PM
I code is 00575 inlet manifold pressure - difference intermittent
might signify a faulty n75 valve...

check the connections to it too

ad4pm
09-02-2007, 08:02 PM
Also noticed that it occured more under load when going up the steep hills round Sheffield! It would lose loads of power, I'd pull up, restart and then fine again till next time.

A main Audi dealer diagnosed it, but turbo was fitted by a specialist tuner that the warranty company directed me to use.

marty67
09-02-2007, 08:04 PM
Is there any way to test these things.?

ad4pm
09-02-2007, 08:15 PM
Sorry, but not sure to tell you the truth about the turbo problem I had.

I was just happy to get it sorted without the hefty bill.

Lets hope its something more straight forward that someone on this forum can help you with.

marty67
09-02-2007, 08:58 PM
what is an n75 valve? where is it and what does it do?

seraph
09-02-2007, 09:12 PM
what is an n75 valve? where is it and what does it do?
its a charge pressure valve, controls the boost pressure ultamately

marty67
09-02-2007, 09:15 PM
where is it and is there any way to test it?

ad4pm
09-02-2007, 09:36 PM
in my manual, the valve mentioned is behind the right headlight, accessed by removing the inlet duct. Sounds like it has a vacuum pipes and a wired plug. Hope this helps!

marty67
09-02-2007, 09:49 PM
thanks. i'll have a look

mr audi
09-02-2007, 10:42 PM
Hi, Ive had this fault on quite a few pd engines. Try the map sensor in the silver inlet pipe,there about £30. Does it show a boost fault on diagnostics. The ones ive done have been around 90k miles,good luck.

marty67
09-02-2007, 10:48 PM
can you explain how to tell if there is a boost fault. i'm a bit new to all this. thanks

mr audi
09-02-2007, 11:06 PM
Hi, get it checked on a code reader. These cars do strange things when other sensors go down making you change parts for nothing. Check the fault memory then clear it, road test it so that it does the fault, then recheck the fault memory, may say boost limit reached or adaption fault.

marty67
09-02-2007, 11:09 PM
i've done that and the code 00575 inlet manifold pressure is the only code that shows

mr audi
09-02-2007, 11:18 PM
Hi, sounds like the map sensor. Have you any breakers near you to try one. Takes 2 seconds to change with screwdrver. Typical as i see loads today at breakers yard.

marty67
09-02-2007, 11:41 PM
where exactly is the MAP sensor as i've had trouble identifying it?

mr audi
10-02-2007, 12:09 AM
Hi, open the bonnet. Take off the engine cover 3x 10mm nuts.look where the inlet pipe goes along the back of the engine and theres the map sensor,its held in by 2 screws and has a plug connector to it.cheers.

marty67
10-02-2007, 12:12 AM
thanks. i'll have a look at that in the morning.

gavinj
14-02-2007, 09:16 AM
I have just bought a 06 A4 Avant (9000 miles on the clock) and have a similar problem. It stuggled getting up the hill, i could drop down the gears and the revs would increase but no increase in speed.

It ended up to be a EGR Unit (Exhaust Gas Recirculation) unit.

USA car junkie
14-02-2007, 11:46 AM
wrong thread

USA car junkie
14-02-2007, 11:54 AM
Adim., remove pls

mcajee
15-02-2007, 03:14 PM
Hi,
Have a similar problem Audi 1.9TDI 2002 looses turbo when revs around 3000 however when engine switched off turbo is OK. Checked MAf , checked and clean pipes , replaced solenoid valve and the problem persists. While checking MAF once again noticed that the air filter was very dirty and cleaned it, not having a new one at the time. The car seems to be running fine now. Will replace the filter today and hopefully the end of my problem