P1123/1125 cel
 

Hi All, Going to try and finally resolve my issue. 1999 Box Base throws a CEL P1123-1125 every 600 miles or so. Engine Leaned out cause of rich mix. I've been just clearing it lately....car runs GREAT throughout. New Plugs/AOS/ MAF/Fuel Filter/Fuel Press Reg/Cleaned and checked output of all injectors/Air Filter/Cleaned TB and Plenum.
Only items not changed is purge valve for the charcoal canister and fuel pump. I believe my Fuel pressure tested at 3.3Bar Engine off and 3.1Bar at idle which I think is on the low side but still within specs. Any thoughts on fixing this?? Thanks V

pull the cam plugs & check your timing?

Timing within spec. Deviation +3 B1/0 B2

give us a little background info.
How many miles???
Any mods including air filter??
Any codes in the past other then the P1123-P1125???
Do you have an OBDII scanner such as a Durametric????
Do you have a way to get the freeze frame info related to the codes???
Do you have a vacuum gauge????Or access to one???

That's cam deviation right?

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.

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.

Ok thanks for the info. I was thinking about the o2 sensors but that would mean 2 would have to be faulty being that both banks are rich.

1st test engine not running just key on?

2nd test engine running to heat up sensors?

1st test key on engine OFF. This test looks for correct voltage signal form the DME/ECU to the sensor.

2nd test key on engine OFF. this test looks for correct voltage to the heater circuit..

The first 2 test just confirm that supply voltages are correct. so key on engine OFF.

The 3rd test is to test the operation of the sensors so engine running.

Yes both sensors would have to be faulty because both banks are rich.

the tests will let us see if they are or not.

OK ,so I'll see the 02 Voltage

02 heater voltage

and then graph them when I open the durametric....

I mean every durametric is pretty much the same.

Vince

Print out post #7
Then hook up your Durametric
Just read post #7
I explained how to do everything step by step
graphs, voltages, what to do to get there everything is explained in post #7
Easy peasy;)
Yes as far as I know all Durametrics work the same.

Ok so here's some data. The Durametric didn't have any Post Cat tests that I could find.

The numbers are hard to read here so they are as follows.

Test1 .44 both banks

Test2 1.8 Ohms didn't have a voltage readout

Test3 .98 at idle both banks (durametric only specifies oxygen sensors cyl 1-3 and cyl 4-6 don't know if its pre or post))

Test3a (Same as 3 but at a different time) seemed somewhat erratic but what do I know.

Somehow my CEL cleared itself while testing. It was not reset cause all my readiness tests all passed when I checked ie. heater/cats/secondary air etc...

sent a PM as well ....I have a video using my torque light on my droid if you're interested. Thanks Again....V

I replied to your PM
So the first graph is some of the info I am looking for.
on the rest of the graphs you have the wrong boxes checked.
I will post here on the thread in the morning and get you pointed in the right direction.;)

Hmmm...I didn't see any other boxes associated with o2.

Ok lets try to simplify this :
Just do a running test.
You want to check the same two boxes you checked in the first test. look at the first graph you posted.
They say: O2 sensor voltage ahead of cat. conv. bank 1
O2 sensor voltage ahead of cat. conv. bank2
Also find: O2 sensor voltage behind cat. conv. bank 1
o2 sensor voltage behind cat. conv. bank 2

with those four boxes checked do the running test with the car warmed up and at idle.

Make sure your testing "VOLTAGE" not oms or anything but voltage;)



Then post the graph;)