Astra 2001 1.6 16v Cutting out / Starting Problems
Hi, please help.
I have a vauxhall astra 1.6 16v 2001. A few months ago the engine managment light came on. I checked oil and water etc and all seemed ok, the car still started and ran fine with the light on. then it started to limit the revs and put the car into limp mode. It always started fine though and I lived with the limp mode as it came and went intermittently. Recently the car has had intermittent starting problems. I turn the key and the starter engages but the car will not fire. It just turns over. however if I then bump start it, the car starts immediately. In addition it has started to cut out when driving. I can be going slow or fast, engine hot or cold, it just stops. The electrics on the dash seem fine, the lights do not go out but the engine just stops. If i am at speed I can turn the ignition off and on to bump it and carry on. I always have to turn the ignition off and on again to restart it when this happens. If I am stationary, it may or may not start from the key as previously described. If that wasnt enough, there are times when it starts perfectly and runs like a dream for hours.
I have had the car in 1 vauxhall and one non vauxhall garage. I have had the following changed
Timing belt adjusted (apparently this can give cam sensor codes iff too loose)
New plugs, Oil and filter changes
Fuel filter change
Injector cleaner put in.
I have checked the Crank sensor with an iscilloscope and saw a beautiful Sin wave, when I checked the cam sensor (new one) i saw a jagged mess. I am not sure if this is due to power being needed to be put through it. I expect to see a castle shaped wave, although no one I speak to seems to be able to confirm this, even vauxhall!
My knowledge of things extends to knowing what I have fixed already so if you have any advice, please be specific. I have read the codes and the only one showing at the moment is P1405 which indicated EGR valve problems (but this is a new one!!! Grrrr)
I have just purchased EngineCheck Software to read codes and live data, I will post results on here when I have run it but to be honest, I could do with any help from experienced mechanics as I am running out of money to keep trying things
The cam sensor works on a sine wave of approx. 100khz frequency. This signal is generated by the ECU and is fed to the sensor, When the raised part of the cam pulley is in close proximity to the sensor it feds the signal back to the ECU which indicates No.1 TDC.
Originally Posted by SESurfer
Switch the ignition on but, do not start the car. Check that there is a good sinewave of approx. 100khz getting to the cam sensor plug. If not I'd suspect wiring and more than likely a faulty ECU.
Thats what i saw from the Crank Sensor, Would you not see a castle shaped one on the can sensor as there is effectively 2 positions on the cam Pully. If you look at it, the pully is in 2 halves with one half being nearer to the centre than the other... I thought that would give a reading of high for one half revolution and low for the opposite half of the revolution.
I have just re-read the codes stored on the ECU
are showing now. Would you believe it, the car is starting fine. When I want it to not work so i can get readings it wants to be perfect....
It could be either depending on which type of sensor is fitted, Either Hall effect or AC excited.
P1405 = EGR.
P0443 = evap valve.
Ok, cool, so what is an evaporation valve and where do you find it?
I think I have sorted out P0443. The plug was not sitting correctly. I have reseated it, cleared the codes and then re-checked. only P1405 showing now. So far the car is starting fine. I am not convinced the starting problem is fixed though.To convienient.
Check the feedback voltage of the EGR valve and post here. Will soon tell you whats what.
Sorry to be a pain, how do I check that?
The enginecheck software has given me this data but nothing relates to the egr valve
Freeze Frame data
Fault code Sensor Value
P1405 Sensor values:
Calculated Load 2.35 %
Coolant Temperature 98. C
Short Term Fuel Trim Bank 1 0. %
Long Term Fuel Trim Bank 1 0. %
Intake Manifold Pressure 30 kPa
Engine Speed 784 rpm
Vehicle Speed 0 km/h
Ignition Timing Advance 5.5 º
Intake Air Temperature 21. ºC
Air Flow Rate (MAF) 2.37 g/s
Absolute Throttle Position 3.14 %
Oxygen Sensor 1 - Bank 1 voltage 0.87 V
Oxygen Sensor 2 - Bank 1 voltage 0.8 V
You are using an OBD system here. No good. Thats why technicians don't use it. Only as a last resort.
Without the EGR feedback voltage I cannot help you further. Sorry.
Sorry for delay in getting the EGR feedback voltage. i will get to it. In the mean time I have been checking some more things. As i suspected, the intermittent starting problems returned. When it happens I am getting a P0335 code, which I believe is
Crankshaft Position Sensor A Circuit Malfunction.
The sensor is a new one, purchased from Vauxhall and when checked with an oscilloscope, gave a good clear sine wave signal that varied with reving the engine.
The wiring plug was a bit mucky so I have cleaned it all up, I have checked the wiring and it appears to be ok, no burns or obvious signes of wear. Is it possible to check the signal that reaches the ECU plug? Again, I have the ECU plug off and checked for bent pins and muck. It was very clean and no obvious signs of wear.
I was wondering if it is possible to completely replace it as I have read that poor earths on these can cause problems. I am basically trying to rule out all options before having the ECU itself checked.
i am determined to find the fault, especially if it is a simple thing rather than rush off and buy new ECU's etc.