Opel Astra 99 (corsa b engine) Please help

AdamLB

I'd really appreciate any help with this.

I have a 99 Opel Astra 1.2 (so its the same engine as the corsa b 99). The car recently failed the NCT on emissions. The car has done 100,000 mls but sounds fine and is has great performance. In the last 6 months I have changed the MAF, the EGR valve, the cat and the lambda sensor. I service the car myself every 4000 miles or so and the car has just had new sparks, oil, oil filter and air filter. I have op-com and their are no faults nor does the engine light come on.
When I plug the emissions reader in the idle reading sits at about about .20 %CO2. However, when I take the high rpm reading the Co2 % fluctuates madly going from .40 to about 2.40 at times. To pass the NCT it needs to be under .3. I have tried everything I can think of and I am about to throw a perfect car on a scrap heap. Any help or suggestions would be very welcome.

crosshair1

Whats the o2 sensor doing at high idle??

shamwari

Using your scan tool, can you see

a) what oxygen sensor is doing?
b) Is the coolant temp reaching normal limits (>70.c)
c) If it is running closed loop (this might not be available in Opcom)?
d) The manifold pressure is reporting correctly

Also, are the spark plugs ok and the engine is not burning oil?

Does the car drive normally?

shamwari

crosshair1 wrote: »

Whats the o2 sensor doing at high idle??

My thinking too

AdamLB

Thaks for the quick replies.

Ok - now you can tell I'm an amateur. I didnt check the O2 sensor at high idle but i will tonight after i give it a good drive and i'll put up all the results. The o2 sensor is brand new though.. as in it has done 20 miles!

Just checked the low idle and it doing about 550-600, 12.4, and open loop. I dont fully understand what these numbers mean.

What should the manifold pressure be?

Ill do a check on the car a little later after ive give the car a good drive and warmed it up and post the results.

thanks
Adam

crosshair1

One other thing is the MAF, on these genuine only, if youve replaced it with one from ebay its not going to work.

AdamLB

OK,

The car drives normally. There was a o2 senor fault (it said low reading/not present). This fault used to come up as soon as the car got up to about 3000 revs. Since I changed that last week there has been a major difference in performance. The car has a 'kick' of old and the mpg has gone up. But that is kinda what I would have expected. I changed the MAF about 3 months ago and thought that it may have been that. I got another one that is known to be working and it made no difference. I changed the EGR valve at the same time (and after paying for that Im not sure it was even broken to begin with).
the o2 sensor reading (mv) bounces anywhere from 60-750. The car has a small oil leak but it has had that for tha last 40000 miles and its got through the 2 previous NCT's with no trouble. Nothing has changed there.
AGain any help or opinion really appreciated.

heres a list of the measuring blocks for low idle and the second lot is for high idle:
Measuring blocks information:


Battery Voltage 14.1 V TPS Signal (Throttle Position Sensor) 0.70 V Idle Switch Closed 0V Mass Air Flow Sensor 7 kg/h Mass Air Flow Sensor 1.42 V Coolant Temperature 96 °C Coolant Temperature 0.88 V Intake Air Temperature 37 °C Intake Air Temperature 2.83 V Transmission Coding Manual Transmission A/C Information Switch (Air Conditioning) Inactive 0V A/C Pressure 0.00 bar A/C Coding (Air Conditioning) No A/C Detected Telltale (Check Light) Off 12V Fuel Pump Relay Active 0V Spark Angle before TDC (Top Dead Centre) 11 °CA Ignition Coil 1 Load Ignition Coil 2 Load Ignition Coil 3 Load Ignition Coil 4 Load Knock Signal Inactive Knock Retard 0 °CA EGR Valve (Exhaust-Gas Recirculation) Inactive EGR Pulse Ratio (Exhaust Gas Recirculation) 0% EGR Position Feedback (Exhaust Gas Recirculation) 0.88 V Fuel Tank Ventilation Valve 0% Desired Engine Idle Speed 780 RPM Desired Idle Air 7 kg/h Actual Value Idle Air 8 kg/h O2 Sensor 771 mV O2 Sensor Loop Closed Air/Fuel Ratio Rich O2 Loop Integrator 116 Steps O2-Loop BLM Idle (Block Learn Map) 135 Steps O2-Loop BLM Partial Load (Block Learn Map) 103 Steps Hall Sensor Inactive Engine Speed 800 RPM Coolant Temperature Pulse Ratio 44.92% Injection Pulse 3.1 ms Engine Speed Pulse Inactive Engine Load Signal 1.6 ms Vehicle Speed Pulse Not Received 12V Vehicle Speed 0 km/h A/C Relay (Air Conditioning) Inactive 12V Cooling Fan Relay Inactive 12V Throttle Valve Angle 4 ° TPS Load Signal (Throttle Position Sensor) 10 Steps Immobiliser Function Programmed Yes Security Wait Time Inactive
Measuring blocks information:


Battery Voltage 14.2 V TPS Signal (Throttle Position Sensor) 0.94 V Idle Switch Open 12V Mass Air Flow Sensor 18 kg/h Mass Air Flow Sensor 1.93 V Coolant Temperature 98 °C Coolant Temperature 0.84 V Intake Air Temperature 39 °C Intake Air Temperature 2.73 V Transmission Coding Manual Transmission A/C Information Switch (Air Conditioning) Inactive 0V A/C Pressure 0.00 bar A/C Coding (Air Conditioning) No A/C Detected Telltale (Check Light) Off 12V Fuel Pump Relay Active 0V Spark Angle before TDC (Top Dead Centre) 31 °CA Ignition Coil 1 Load Ignition Coil 2 Load Ignition Coil 3 Load Ignition Coil 4 Load Knock Signal Inactive Knock Retard 0 °CA EGR Valve (Exhaust-Gas Recirculation) Inactive EGR Pulse Ratio (Exhaust Gas Recirculation) 0% EGR Position Feedback (Exhaust Gas Recirculation) 0.88 V Fuel Tank Ventilation Valve 0% Desired Engine Idle Speed 1.300 RPM Desired Idle Air 9 kg/h Actual Value Idle Air 22 kg/h O2 Sensor 112 mV O2 Sensor Loop Closed Air/Fuel Ratio Lean O2 Loop Integrator 122 Steps O2-Loop BLM Idle (Block Learn Map) 135 Steps O2-Loop BLM Partial Load (Block Learn Map) 103 Steps Hall Sensor Inactive Engine Speed 2.680 RPM Coolant Temperature Pulse Ratio 48.44% Injection Pulse 2.8 ms Engine Speed Pulse Inactive Engine Load Signal 1.3 ms Vehicle Speed Pulse Not Received 12V Vehicle Speed 0 km/h A/C Relay (Air Conditioning) Inactive 12V Cooling Fan Relay Inactive 12V Throttle Valve Angle 9 ° TPS Load Signal (Throttle Position Sensor) 22 Steps Immobiliser Function Programmed Yes Security Wait Time Inactive

crosshair1

Can you reset BLM values with the clone version of Vaux/Op-com
post a part no of maf fitted.

AdamLB

i might sound like a tool asking this.. but what are BLM values?

AdamLB

the part number of the MAF is pbt gf30. The one I put in is not Bosch.. its by an English company called commercial ignition (CI). I know putting in parts that are not orignals carries risk, so I got another new bosch one to test the other day and the results were exactly the same. Also, my CI one gave perfect readings in another car.

crosshair1

Youve posted the BLM values in the live data, they are basically how far away the ecu thinks its fuelling is from a predetermined map stored.
They are zero at a value of 128 meaning that the ecu stored map is identical to the fuelling from the maf/o2/cts/egr..
See if you can reset these as they will correct the problem straight away if the sensors you have fitted are satisfactory.
gf30 is not a part no, something like 0 203 022 122 is.
These gave so much grief with mafs its not advisable to fit non genuine (I have the tshirt(s) dont ask)

AdamLB

OK Ill give that a try. One more thing that i think could be relevant.. since i've got the cat changed, when the car is stationary there is a light smell of exhaust that comes in through the dash air. It was never there before. I read this on another form. Might this have anything to do with it?

"If the mixture is too rich, strangely there might be a change that there's an air leak in the exhaust system - possibly post Cat but pre-lambda. This might fool the ECU into thinking that there's too much oxygen in the exhaust, and as a consequence the ECU will doubtless enrich the mixture. The Cat will probably then have too little or no oxygen to enable it to 'burn' any CO or HC emanating from the engine. Which I would guess would then result in both oxygen and high CO reading from the exhaust - emissions fail."

The other number on the MAF is 0 280 217 123
Thanks
Adam

AdamLB

I was able to reset the blm values but nothing has changed. I've tested all of the new parts in other cars (except the new cat) and they all work perfectly. Is there anything else apart from these parts (EGR, MAF, CAT, O2 sensor) that it can be??? I'm at my wits end and beginning to really hate the car!

shamwari

Havea you done an emissions test since?

AdamLB

Yep,
The emissions bounce all over the place still. Low idle it sits at about .2% and high idle it swings madly from about .4% to 2.5% and even sometimes to 4%. It was doing exatly the same before I changed the CAT.

shamwari

That's as odd as two left feet!

Is you Gas Analyser spot on? Can you test it on a known good car to be sure?

If you keep the revs constant at a fast idle and look at the live data from the O2 sensor, is it switching fast and consistent? If it is inconsistent, is there a relationship between the inconsistencies and the periods of excess emissions?

Also, there's definetly no leaks in the exhaust? And there's no rattles from inside the CAT?

AdamLB

There are no rattles from inside the CAT, but I'm thinking that the light smell of exaust that comes out of the dash when the car is stationary might be leak?

AdamLB

I've just found a very small leak in the exhaust manifold before the CAT. I can’t believe I didn’t see this earlier. I'll be taking it apart tomorrow and either getting a new one or putting it back together properly. It is only a small leak...so would that cause the emissions reading to fluctuate so wildly???

shamwari

AdamLB wrote: »

I've just found a very small leak in the exhaust manifold before the CAT. I can’t believe I didn’t see this earlier. I'll be taking it apart tomorrow and either getting a new one or putting it back together properly. It is only a small leak...so would that cause the emissions reading to fluctuate so wildly???

Yes it can as the effect of four cylinders firing into one exhaust can create a pulsing effect where exhaust gases are expelled out through the leak and then ambient air can be sucked in. Hopefully this is the cause and when fixed puts to bed a fault that is clearly a heart breaker.

dazza27

as an opel dealer i have seen many times that spurious cats just dont work - this could be your problem ??

Lucifer

A leak around the manifold or anywhere before the cat/o2 sensor will cause you emissions to be all over the place.

AdamLB

It may well be the CAT but it's behaving exactly the same way after I put a new CAT on. I would have expected it to be some way different i.e. higher or lower if it was the cat but as it is I think I've just paid a bomb for a new CAT I didnt need. The only way to be 100% would be to buy an opel CAT or get one second hand: new Opel quoted 1200 euro (I won't be buying another Opel just for this) and second hand I found one in Galway that the guy told me had done about 150000 miles...so eh...no. I don't think it needed the O2 sensor, EGR and MAF either I spent a fortune on this car (way more than it's worth). I fixed the leak around the manifold and still nothing. At high idle CO2 sits at about .2% and then swings madly to about 2.0% and then back down again. I not a machanic and just don't have the money to keep at it so I'm putting it up for sale. Any machanics are very welcome to give it a go! I'm not dishonest so I will be giving the lowdown to any buyer! I'll be both sad and happy to see it go.

AdamLB

Here's a mad idea I thought someone might be able to help me on... could I slap on a second catalytic converter? I was thinking of just picking one up from a brakers yard and putting it on after the first one. Sure it would fix the source of the problem but surely it would reduce the emissions???