Quote:
Originally Posted by Vza
Yes Cam Deviation.
140,000+ miles
No Mods
Lots of CEL's in the past. I had replaced a solenoid and burned resistor in the DME had misfire codes and more. Lost timing at one point but those issues resolved.
Access to vacuum gauge.
Have Durametric
Not too sure about freeze frame.
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So here are my thoughts:
A few things than can cause to rich a mixture.
To high a fuel pressure:
Leaking injectors.
A sensor that is giving the DME/ECU false readings.
So the DME/ECU can be fooled into thinking mixture is to rich.
I went back thru most of your threads and I see that your vacuum looks good.
Also that you have tested the fuel pressure and the fuel regulator in the past.
Also that you replaced the MAF sensor.
O2 sensors can give the DME/ECU false reading if the become "biased" high or low.
If they become "biased" high the DME/ECU sees that s a rich condition and trys to drive the O2signal low by taking away fuel.
So I would look at the O2 sensors with your Durametric.
First test:
Hook up the Durametric key on engine off.
click on the engine module then click on actual values.
Find O2 sensor volt for all 4 sensors.
check the boxes.
you should get a reading of 0.45mv on all four
That will check the signal from the DME/ECU
Second test:
look for O2 sensor heater circuit
Check those boxes the voltage should be 4.30V-4.50V
That will check the voltage from the DME/ECU to the O2 sensors heating circuit.
Third test:
Take the car for a drive and get it up to operating temp.
Hook the Durametric back up.
With engine running this time... go back to all four O2 sensor voltage signals
Graph then for 3-5 minutes at idle. dont rev the engine just let it idle.
The pre cat O2 signals should go up and down in a constant sine wave pattern.
The post cat O2 sensor signals should stay above .450mv and spend most of the time at around .650mv-.750mv
Post the graphs f you can so I can look at them.