Take the 2-minute tour ×
Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. It's 100% free, no registration required.

I have a problem with my car. My car:

BMW 330D, 135kw, 2001 year, E46.

A week ago my turbo charger got broken when I was driving. There was a lot of white smoke going out of exhaust and there was no power. I bought a new turbo charger and changed it. Now the strange thing is happening: when I press the accelerator there is no power until the rpm tachometer reaches 2500, then I need to release the accelerator and then press it again and only then the power is back.

There was not anything like before with an old turbo charger. Maybe someone know what might be wrong?

share|improve this question
    
Does the turbo have an internal or external wastegate? –  Timo Geusch Jul 19 '12 at 19:01
    
My turbo has external wastegate. –  Paulius Matulionis Jul 19 '12 at 19:58
add comment

2 Answers 2

up vote 3 down vote accepted

Two possibilities occur to me: a too-large turbo or a too-loose wastegate.

when I press the accelerator there is no power until the rpm tachometer reaches 2500

This almost sounds like the replacement turbo is too large.

when I press the accelerator there is no power until the rpm tachometer reaches 2500, then I need to release the accelerator and then press it again and only then the power is back

Look at the whole combination, I wonder if the wastegate is staying open until you release the pedal and then re-apply. Do you have a boost guage? If so, are you seeing a slowly building boost with a sharper increase at 2500?

Note: even without a boost guage, you should be able to hear the turbo spinning up. If I drive with my windows up, radio and vent fans off, I can hear the turbo spin up and blow off in sync with the boost guage.

EDIT: based on the comments, I have to think that either the wastegate or the blowoff valve is opening when it should not. If the turbo is spinning, the wastegate has to be at least partly closed (to enable the exhaust gases to spin up the turbo). If the blowoff valve is opening at an odd time, the turbo could be spinning but venting the boost in a non-useful way.

share|improve this answer
    
Thanks for your reply. The turbo is not too large. It is exactly the same model as was before. About wastegate, I do not know I will check it and then let you know. But probably this will be the problem. Other people told me to look at it also. Unfortunately I do not have the boost guage, but I hear the turbo spinning up. –  Paulius Matulionis Jul 19 '12 at 16:35
    
Thanks, I thing that the problem is with the wastegate, I probably should have added the old one to new turbo and it would not be any problems. But now I will try to adjust the wastegate on new turbo and see what happens then. –  Paulius Matulionis Jul 19 '12 at 19:58
    
I ran the diagnostics on my car and the problem was with the EGR Valve, how do you think? Might this cause that there is no power? It I should take it off, clean it, and put it on to see what will be? –  Paulius Matulionis Aug 9 '12 at 12:26
add comment

Have you checked for boost leaks, or rather the absence of them? It's very easy to put the various piping back together and it looks like it is fitted correctly, but you still might end up with a boost leak.

share|improve this answer
    
This is also a good source to consider - a loose connection to the intake might cause some of these symptoms. –  Bob Cross Jul 19 '12 at 20:21
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.