Engine Management light on an Astra 1.7 cdti
I have a long standing problem with an engine management light that keeps coming on Astra 1.7 Cdti on a 54 plate. When I exceed 80 mph and then decelerate. the light comes on and my rev counter will not go above 3,ooo rpm. I have taken the car to vaxhaull who have tech 2 tested it and come up with an air mass leak. They decided that the EGR valve needed replacing. I had the work done and one week later the light again came on again. Since then I have had my software for the ECU updated, a new air mass flow meter fitted and various minor adjustment done and still the light comes on. I have taken the car to a specialist diesel expert who have suggested that it might possibly be the waste gate sticking. This was only a possibility. To remedy this they suggested either a new turbo unit or have the old one repaired. My concern is that this is only a possible cause and may not in fact cure the problem. I would like to know, if I choose to do nothing and except that at a certain speed this engine management light will come on and stay on until I turn off the ignition, will this damage my engine. For financial reasons I feel that I should perhaps wait until the turbo goes and then I will definedtly know that this is the root of my problems. When this light appears I can still get 70mph out of the car. Is this a good idea? Anyone else had the same sort of problems? Can anyone else give advice on what to do? I would be very grateful as I am at the point of exasperation. I am reluctant to get rid of the car as apart from this minor problem it runs well.
Last edited by deborah; 16-01-09 at 16:42.
This is an identical problem to a 54 plate Zafira 2 litre turbo diesel that I am doing. The customer has repaced the EGR valve because fault code P0400 comes up again and again. He's had the inlet manifold and flap valves decarbonised, new airflow meter etc just like you.
In this car, let it idle no problems. Rev it past 3,000rpm and lift off and the light comes on. Try to rev again and it blocks at 2,800-3,000rpm. Switch off, restart and its ok again.
When its in this reduced mode, with a scanner connected, clear the fault code and it is instantly fixed. Till next time.
With the EGR valve removed, and operated by the scanner, its working correctly. Checked the bottom pipe from the vacuum pump for oil but it was clear. So now compared the boost solenoid 'command' value against the 'actual' value. While running ok the values were very similar. When in silly mode, the actual value remained at the idle setting. Operated the solenoid countless times using the scanner and the fault disappeared and car drove fine.
On your engine (1.7 CDTi engine code Z17DTH or DTL)the equivalent part is the turbocharger control solenoid. Before going to the expense of a new turbo/actuator, perhaps worth trying this first?
My customer has not as yet come back to me so I do NOT know if this is a fix. I am making enquiries with a Vauxhall master technician for more info. Will post if and when..
I think the garage was right about it being a problem to do with the wastegate but, I don't think it is the turbo itself that is the problem.
I think Hometune is nearer to the problem in that it is most likely the 'control' of the wastegate that is at fault.
Think so because when it is not revving past 3,000 and the light is on, if I press the accelerator and at the same time, clear the fault code it instantly clears. That seems to point to an electrical problem as the scanner has no direct mechanical control over the actuator.
does it measure the boost pressure with a map sensor? If so I'd be inclined to check it with a scope.
Yep, the boost pressure (map) sensor is fitted into the housing just before the EGR valve. I have known them become blocked so removed and cleaned it as it had not been done when manifold removed and cleaned.
Don't have a scope at present - waiting till I can afford a Bosch KTS with dual scopes.
I'm toying with the Idea of buying a Picoscope next time. Although they are not so convenient as a hand held.
Thank you Hometune, I'm still none the wiser as what to do next. Have spoken to the garage and suggested that I might leave it until the problem becomes alot worse ie. the light on more frequently. At present it seems to only come on when i'm doing 80mph overtaking and then decelerating. The garage reckons that when they took it out for a test drive they could get the light to come on in urban driving by taking their foot on and off the throttle not a problem I have had. They mechanic suggested that if it was not the waste gate it could be the ECU on its way out hope thats not correct as it will be mega bucks. If I do nothing will I damage my engine? As far as pressures and values they reckon that they are all normal and therefore it is the waste gate sticking. Can I get the soleniod that your talking about checked easily and who do I go to? All your advice has been very helpful, thanks again
Last edited by deborah; 17-01-09 at 10:43.
The solenoid can be checked using a scanner with the Vauxhall software or of course Tech2.
The Vauxhall master technician is still looking into mine but we are coming to the conclusion the EGR valve is a faulty replacement. Hmmm...
Should hopefully know something by Mon or Tues and I'll post here either way.
You're unlikely to do any damage.
Thanks for your message, perhaps I will not rush out and get the work done until the problem becomes more persistent. I seem to be learning about the engine as I go along and coming to the realisation that even the experts are never sure and take the opinion that to fix the problem they will go through a whole mass of components until they get it right. When I first had my EGR valve fitted and the problem reappeared a week later I went back to Vauxhall having looked on the internet and hearing about numerous faulty valves they assured me that the valve was ok and that perhaps the manifold and swirl flaps needed cleaning. Excuse my ignorance but is any of this to do with the waste gate? The diesel expert that I then took my car to said they looked ok. Hope your problem gets sorted soon await your message