No power! please help :-(

[dukey406]

Having a great deal of grief with the 406 at the moment. Intermittantly, she has hardly any power. No engine management light or error codes. Basically, from cold she seems ok but as the engine warms up I get the symptoms, while maintaining a constant speed on the bypass, the power fades out and you have to sink your foot to the carpet to maintain 60mph. Dip the clutch and let the revs drop to tickover and let up the clutch and the power seems to return. Also, flat out in any gear, the car seems to surge in and out of power.
Enginge sounds nice and sweet, uses no oil or water, doesn't overheat, brakes are fine. Turbo makes the right noises etc, any ideas?

[grasmere59]

Fuel filter change? My old diesel Escort van used to do that when the fuel filter needed changing.

[martint]

Let us know what was wrong. Itching to know

[dukey406]

Problem getting worse now, when it happens if you put the car in neutral and press the accelerator right down, it doesn't seem to want to rev above 3000rpm and makes a noise like bouncing off a rev limiter. There is quite a bit of black smoke when it happens too...

[Doggy]

Difficult one to get your head round this - please don't think we don't want to help, but I guess everyone's unsure and nervous of suggesting the wrong thing, costing you money & not helping.

The stock answer is get it diagnosed, but to have issues like these without the EML, is strange and maybe diagnostics won't show anything, but I still think it's the best place to start.

[marty1979]

There is quite a bit of black smoke when it happens too...

Black smoke would indicate a lack of air, as in a restriction between the air filter and inlet manifold.

[madmadmax]

i would start by looking for boost leaks and having a look at the air and fuel filter.

[dukey406]

Thanks for replies, I'm going to investigate now got a few things to try

[keppler]

As madmadmax said, try checking for boost leaks. Also try unplugging the maf sensor and taking it for a spin.
Any chance you have a sticky egr valve? Try unplugging the vacuum pipe.

[dukey406]

Just a quick update.
I've tried, disconnecting the vacuum pipe from the EGR valve and blanking it off. This produces the fault described all the time, IE no boost, smoke and surging no power etc.
Does the EGR need a vacuum to make it stay closed on this engine?
Would it be better to disconnect the solenoid valve electrical connector instead?

Particularly bad today on the way home, seems it is worse when stopped and driven again within an hour or so.....

[6speedmanual]

No vacuum to turbo wastegate - fails open. No boost.
No vacuum to EGR - fails closed.
Sounds as if your EGR may be stuck open.

Try gently tapping the cast iron base of the valve. This may dislodge the stuck valve plunger.
Or take it off and clean it.
Another option is to fit an EGR blanking plate in the pipe to see if the symptom goes away.

Peter

[keppler]

To check if the egr valve is sticking open disconnect the vacuum pipe to the egr valve. Put your hand around the brass pipe connected to it and get someone to start the car and rev it immediately. If the egr is stuck open then you should feel heat from the pipe fairly quickly.
Just for reference, Ive tried this on my car which has a perfectly functioning valve and the pipe stayed cold for over 1 minute and counting till i turned off the engine.

[dukey406]

Thanks for the info guys. I had a whole lot of trouble with my Astra and egr valves, ended up blanking that off too. Can anyone suggest the quickest way to blank it off?

[keppler]

You can buy blanking plates on ebay for around a fiver. You will have to take off the valve itself and place the plate underneath the valve and bolt back into place the valve.

[dukey406]

I'm really not sure about this one.
I've tried blanking the egr vacuum pipe this morning at the actuator end. The fault wasn't present before I did this (not too bad from cold).
When I fired her up, no turbo boost, smoke and surging, lethargic struggled to rev past 2500rpm in neutral.
Connecting the pipe back to the egr valve bought the car back right again.
I'm really confused, this is why i asked if the vacuum holds the valve shut? - am I doing this the right way around?