30000 revs spanner light .limp mode .vectra 2.0 dti 2004

[davemander]

HI All
Looking for help for an ongoing problem
2004 Vectra c 2.0 dti
Car drives fine if kept under 3000 revs , hit 3000 revs and the spanner light comes on (limp mode ?) no other lights . turn ignition off ( bump start ) -light goes out continues to drive fine unless you hit 3000 revs again , when on the drive and out of gear it will happily rev to near red line
I have cleaned the egr valve ,cleaned boost sensor
I have had it on op-com and no faults registered except low voltage on glow plug .
Thanks in advance for any replies
Dave

[jonnyaykroyd]

Could this be turbo over boost? If the VGT vanes in the turbo exhaust turbine housing are sooted-up and sticking in the closed position then an over boost condition will occur at high engine speeds.

As you say car is fine at low revs (vanes need to be closed for max possible boost) but should open as engine speed increases. It's unlikely that over boost would occur with vehicle parked as engine needs to be loaded to really "work" the turbo.

Can you see if the actuator on the turbo is moving freely; this would indicate whether or not the vanes are stuck What are the MAP readings like when limp home is triggered?

[davemander]

Many thanks
Will check the actuator tomorrow , If I can figure out how to use the op-com I purchased recently might be able to get some readings myself ?
Dave

[Signum-Steve]

Check all of your vacuum pipe work as the rubber elbows and connectors perish and split. Also check the boost pipework for splits the pipework from the inter cooler to the TB inlet. Have someone rev the engine hard while you listen for splits. The boost pipe will expand when booted. This is a very common fault on the DTI and the simplest to fix. No faults will be registered with these pipe work faults. leave your turbo alone until you have done/ruled out the simple stuff first.

[davemander]

Appreciate the help given and have checked for leaks on pipes but none found, The only air pressure I could feel seemed to the coming out of the back of the silver round thing ( looks like the old advance / retard unit ) on the back of the actuator , which has a thin black pipe going to a bit on the air filter ?
look forward to any more information
Thanks
Dave

[jonnyaykroyd]

Found this info on a yahoo answer page (just copied and pasted) - possibly some things you could check here:

P0234 Boost Pressure Control Circuit Positive Deviation. (The boost pressure is too low)

I have had a few Zafiras that triggered this code due to the oil level being too low. Have you checked the oil level.
It is critical on a engine driven vacuum pump not to let the oil level get too low or the vacuum pressure will drop below 10hg. When the oil level is max the level will double to almost 20hg of vacuum pressure.

My advice like i said before get the Vacuum system checked with a vac gauge. If the vacuum pump/ brake servo pump isn't holding 20hg of pressure when you have the correct oil level then the pump will need replacing.

The Waste gate could be stuck open causing loss of boost this is controlled by the waste gate actuator that is vacuum controlled this is why i would check the vacuum first.
If there is no vacuum present the waste gate actuator wont open. The waste gate is located in the turbo/ egr intake port to see if this is stuck the turbo charger will have to be removed. You can test the Actuator rod manually with the engine running: looking at the turbo you should see a metal threaded rod that connects to the turbo one end via a pivoting joint the other end is the actuator. You can gently try to move the rod with the engine running if the rod is easily moved then there is no vacuum present. If the rod is hard to move then the correct vacuum is present then indeed the fault will then may be caused by the waste gate flap being stuck open. When the flap is stuck open the engines tone will sound louder as similar to a transit diesel when under load.

[davemander]

HI
Checked oil level and still at max level, but I have noticed that when I drive up a hill and hit the throttle the engine tone does change and sounds a lot louder similar to loud tappet noise I used to get on my old petrol Astra when low on oil . will now sort out a pressure test as you advise ,
will post when I have some answers
Thanks
dave

[DTi Elite]

take the engine cover off & have a good check of the boost hose that comes to the top of the engine , these have a habit of splitting just under the cover .
failing that you need to check all the vacuum pipes .