I've been crying for the last ten days...
Discussion
...Infact my Griffith 500, specially when cold but also when pretty warm, starts venting from the exhausts a strong smelling like uncombusted fuel...it makes you cry like a spoiled baby, specially if caught in traffic...and meantime the engine goes like crap, misfires and doesn't keep the idle...
Just a few days ago the engine went strong and sweet, I didn't touch anything, this f
ng malfunction just started (and keeps going on) from nowhere...
Any inputs?
Just a few days ago the engine went strong and sweet, I didn't touch anything, this f
ng malfunction just started (and keeps going on) from nowhere...Any inputs?
Could really be lots of things. What we don’t know is it just running very rich or is it not burning some of the fuel. Perhaps it would help if you went to the local MOT place or in fact almost any reasonable garage and got them to stick a gas analyser up the exhaust.
As said if it is running rich could be the AFM, or more likely the connections onto the AFM were they get squashed up against the bonnet. Could be an injector sticking open. Or could be one plug not firing. If it runs rich and rough cold and hot would think perhaps not the temp sender.
As said if it is running rich could be the AFM, or more likely the connections onto the AFM were they get squashed up against the bonnet. Could be an injector sticking open. Or could be one plug not firing. If it runs rich and rough cold and hot would think perhaps not the temp sender.
Thanks for the inputs and advices.
So,I'll start with the (black larger Bosch) AMF connections, then the temp sender in the inlet manifold...BTW where exactly? I have a carbon triple plenum...then the plugs and the injectors.
Actually injectors must be pretty savaged...the car is a '96 model and I'm the only keeper from day one, and from what I remember the injectors are still those that came with the car 13 years ago and I only cleaned them once a few years ago...should I change them streight away? Even if they're not the cause of the malfunction?
Also, I have a fuel pressure regulator, maybe it sends too much fuel time by time? 2.5 of pressure should be ok?
Thanks again.
So,I'll start with the (black larger Bosch) AMF connections, then the temp sender in the inlet manifold...BTW where exactly? I have a carbon triple plenum...then the plugs and the injectors.
Actually injectors must be pretty savaged...the car is a '96 model and I'm the only keeper from day one, and from what I remember the injectors are still those that came with the car 13 years ago and I only cleaned them once a few years ago...should I change them streight away? Even if they're not the cause of the malfunction?
Also, I have a fuel pressure regulator, maybe it sends too much fuel time by time? 2.5 of pressure should be ok?
Thanks again.
If it goes open circuit the ECU will overfuel, but I tried putting a variable resistor in series with it to see if I could richen the mixture at will, but no the ECU just kept on pulling the mixture back in line until I had added an extra 1k ohms to it ( at 80'c) so even if the values a tad out it does not matter that much. AFM is still the best bet. Heres MA take on the subject:
With thanks to Mark Adams of TornadoSystems.com
Note that you can drive without an airflow meter in case of emergency (i.e. airflow meter disconnected), because the system will drop into a default (limp-home) mode based on throttle opening.
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine).
The next test is full load, and as with the fuel pressure test it will require use of a rolling road or a steep hill in the same manner. Under full load the voltage should rise to 4.45 Volts (3.5 Litre engine) to 4.95 Volts (5.0 Litre engine).
On this injection system, the idle CO mixture adjuster is provided on the airflow meter. It is located in a boss on the top of the airflow meter, pointing towards the engine. Leaving the multimeter negative probe in the Red/Black wire, move the positive probe to the Blue/Red wire.
Now turn on the ignition but do not start the engine. Observe the voltage. The normal adjustment range is between 0.0 and 3.6 Volts, with the higher Voltages producing higher idle CO values. There are approximately 20 turns of the adjuster screw to cover the entire range.
Annoyingly, the adjustment may be clockwise or anticlockwise to increase the value, and this varies from meter to meter! For this reason it is always preferable to have the multimeter connected in this manner when adjusting idle CO, so that you see can something is actually happening.
Typical Voltages that would be found at this point are between 0.9 to 1.4 Volts for non-catalyst cars. This Voltage is always factory pre-set to 1.8 Volts for catalyst vehicles. A value near to 3.5 Volts will generally produce an idle CO value of 9-10%. These Voltages may be used as safe initial values particularly if no CO measuring equipment is available.
With thanks to Mark Adams of TornadoSystems.com
Note that you can drive without an airflow meter in case of emergency (i.e. airflow meter disconnected), because the system will drop into a default (limp-home) mode based on throttle opening.
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine).
The next test is full load, and as with the fuel pressure test it will require use of a rolling road or a steep hill in the same manner. Under full load the voltage should rise to 4.45 Volts (3.5 Litre engine) to 4.95 Volts (5.0 Litre engine).
On this injection system, the idle CO mixture adjuster is provided on the airflow meter. It is located in a boss on the top of the airflow meter, pointing towards the engine. Leaving the multimeter negative probe in the Red/Black wire, move the positive probe to the Blue/Red wire.
Now turn on the ignition but do not start the engine. Observe the voltage. The normal adjustment range is between 0.0 and 3.6 Volts, with the higher Voltages producing higher idle CO values. There are approximately 20 turns of the adjuster screw to cover the entire range.
Annoyingly, the adjustment may be clockwise or anticlockwise to increase the value, and this varies from meter to meter! For this reason it is always preferable to have the multimeter connected in this manner when adjusting idle CO, so that you see can something is actually happening.
Typical Voltages that would be found at this point are between 0.9 to 1.4 Volts for non-catalyst cars. This Voltage is always factory pre-set to 1.8 Volts for catalyst vehicles. A value near to 3.5 Volts will generally produce an idle CO value of 9-10%. These Voltages may be used as safe initial values particularly if no CO measuring equipment is available.
Gassing Station | Griffith | Top of Page | What's New | My Stuff