1.9tdi engine surge and loss of turbo power

[REDLooP]

Hi, kinda new on here,

Have a problem with our 1998 a4 1.9tdi with 200k miles on it

surges to 2500rpm when started an then doesnt have any turbo power, feels like a straight deisel. It also has a engine light on,

does anyone have any ideas????


Many thanks Nick

[ini]

Hi Nick, any smoke on startup?

Do the revs stay high, or drop straight back down?

Does it do it on both hot and cold starts?

Could be a number of things like a bad coolant temp sensor, or leaking injector, or too much oil getting into cylinders (turbo seals), or even fuel shutoff solenoid.

You need to get the fault codes read to help pinpoint the problem.

[REDLooP]

No theres no smoke on start up

revs drop to normal idle after start

It does it on both hot and cold starts.

Did a few searches an heard things about boost vacume pipes, and fuel pump valve.

I know one of the vacume pipes is a little dodgy so might try sealing that up an see what else happens.

[ini]

The loss of VNT/EGR vacuum is most likely the cause of the revs and the power loss.

[teve2]

I have the same problem, engine blips upto 2000rpm on ingition and the drops straight back to 900rpm, there is a little blue smoke on start up but not when running. I also have circa 20% loss in power.

What is VNT/EGR vacuum?