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Discussion Starter #1
Folks, I did a few searches here for this particularly vexing error code (1223) and got lots of confusing information about error code 1224, so I thought that it would be appropriate to ask clean some slate questions here about this one...

Cold start is very rough and the cold idle is lumpy (with the revs oscillating - almost like a vacuum leak) and slowly rising, before dropping rapidly when the engine is still cold!)

The car runs great when it is warmed up! Idle is smooth when the car is at operating temperature. I have verified the cam timing to be correct. We double checked for vacuum leaks. I have also switched the thermostat sensor with another that I am pretty sure is a known good unit. O2 sensor is a fairly new low mile unit.

What gives?
 

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24V 94 or 95 or 12V?
I would check Bosch motronic sensor wiring.
Check fuel related parts, fuel filter, etc…
Checked plugs?
All ignition connections are clean?
 

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The symptoms you describe sure do sound like it would a cold start sensor problem. The same as my 91S before I changed that sensor not long ago.

Are you sure you switched the proper sensor? It should be the left hand one in the thermostat housing, looking aft at the engine. Also check the wiring for that, as both the connector and wiring sometimes go south.
 

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Discussion Starter #4
Thanks, yes, I have the correct sensor involved...

The car just got fresh coils from you Jason (and with it, fresh plugs, belt change, cam timing verified etc.) Problem before and after...
 

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Have you cleaned the ignition multiconnectors under the air filter box, and also the big round connector at the rear of the engine?

With problems like this in the 24V engine, actually both that and the 12V engine, it pays to clean all the electrical connections in the engine bay before digging too deeply into other ideas. Just gets that out of the way.

I also think I would try a sensor which is new. The aftermarket ones are cheap, and they work OK. That's what I use.
 

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Discussion Starter #6 (Edited)
Thanks Del.

Keep in mind that the car runs 100% when up to operating temperature... Something as simplistic as dirty connectors on the main harness connector, or on the two ignition modules next to the air box, would trigger a rough running condition when warm as well...

Is there a part number for that aftermarket sensor, or a brand, or model / vehicle to reference?
 

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"Something as simplistic as dirty connectors on the main harness connector, or on the two ignition modules next to the air box, would trigger a rough running condition when warm as well"

Oh, not necessarily. Perhaps a rash assumption. My 94LS had those dirty connections, and yet it could run well at speed and at hot engine temperature, but when cold or wet could act up. These symptoms were similar to the bad thermostat sensor symptoms in some similar respects. Cleaning those connectors cured that problem. If this is a 24V engine, it just doesn't hurt to clean the connections since it's very easy.

It appears that the sensor in question is common to all 164's sold here, 91-95, as well as some Milano's, Alfa part number 5972332.

Just look in eBay under "Alfa 164 coolant temperature sensor" for various descriptions of the unit. Should be able to find a similar part at a local auto parts store. I bought one of the ~$15 versions (with free shipping), but I'm sure it is available locally since it is used in many cars.
 

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The CTS temp sensor at the thermostat housing is Bosch # 0280130026, at least for the 12v cars. From the discussion above, it seems that both the 12v and 24v cars share the same sensor. Rockauto has them (genuine Bosch) for about $14, but you have to search by part number - they don't show up under the 164 catalog.
 

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Discussion Starter #9
Thanks guys! And yes - a 24 valve (1995) car...

Del - perhaps I'll go after the dirty connectors checks...

I'll get a brand new sensor coming as well!
 

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Whenever I have had the 1223 code, it was always cured by replacing or cleaning the Idle Air Control Valve (IAC). It will act like an air problem (which it is) if it is not functioning as it should. Carbon tracks inside from age and use can cause them to have dead spots as well.
Charles
 

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When you clean all those connections, be sure to protect them with dielectric grease to keep out dirt and moisture, esp the ones under the air cleaner, as they are in a vulnerable spot there behind the grill, collecting all sorts of crud.
 

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I think you still need to check the timing again and follow the TSB procedure to a tee. This engine is super precise. If it is just a tad out it can typically run better once the motor becomes warm due to thermal expansion, thus bringing the motor more into the correct timing perimeters. It may be a long shot but I really suggest making sure it is perfect.
 

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Discussion Starter #13
I've done - what - 50 timing belts on the 24 valvers over 10-12 years...? I don't know much about a-LOT in this world - granted, but if there's something that I DO know, it's timing on a 24 valve Alfa Engine...

Far be it from me to make a mistake, but I checked it. Checked compression - the two banks are balanced (clear sign that one side is not off...) Also, marked the pulleys - most recent positions are verifiable externally then too.

Anyway, replaced the sensor with a brand new Bosch part obtained locally, cleared the codes, lasted all of 5 minutes... 1223 is back. The car was already / still pretty warm, so I'll see what the cold start looks like in the morning. Expecting no change though - given that we still have the same CEL.
 

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On my 1993 164L the "check engine light" was on when the engine warmed up and I was getting code 1223, which I think is the code for O2 sensor. The engine ran fine, cold and hot. I checked MANY things. Finally I checked the signal voltage from the O2 sensor and it was incorrect, the voltage reading was steady, the voltage should fluctuate rapidly between 0.20 and 0.80 volts, approximately. I replaced the O2 sensor and the check engine light went out, (I don't recall if I rechecked for code 1223).

There are three wires going to the O2 sensor, I checked the signal voltage at the single wire/plug located in the area of brake fluid reservoir. I found the process to check the voltage by GOOGLING. If you want more info let me know, I will then try to find it.
 

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I am just telling you that I talked with Jamie Porter in the UK a few times about this issue with these engines. I am just trying to help dude! I knew a new sensor would not clear the problem, it typically doesn't.

Here are some more dumb questions:

Have you checked the integrity of the CAT? I have seen many issues with 24V cats in the past years with a 1223 code.
Have you confirmed the thermostat working properly?
You have confirmed voltage from O2 sensor cold and hot.

A thorough diagnosis should be made for any problem before parts are substituted in my opinion.
 

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Two other things that can give you 1223 besides what I suggested yesterday JJ.
1. Air pump in 95 car supposed to come on for about 90 seconds at startup. If it does not turn off (ie relay sticky) it will throw 1223
2. EGR - 95 car has pierberg valve / EGR system. If it is leaking (either the valve is leaking, or the interface valve/intake is leaking(ie missing the copper washer/ metal gaskets etc) you can pull air thru there that is unmetered.
3. I have also seen where a out of cal Airflow meter can yield 1223.
 

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My 94Q has this error too. Check engine light is mostly off now, however, after injectors cleaned, new fuel pressure regulator. But it still throws the code.

We'll keep working on a solution.
 

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I *think* you said you replaced the sensor with a brand new one, correct? If you haven't done that yet, it's time to do it (unless it's already had the problem with multiple sensors). Even if this one is fairly new, low mileage that doesn't mean much: I have seen them fail.

Do not add anti-sieze to the sender when installing it: that can kill the sensor if you use the wrong type of anti-seize. New Bosch O2 sensors come pre-coated with sensor-safe anti-sieze.

If you get a universal sensor kit, do not solder the sensor wires, use the included crimp connectors.

If the sensor is new, next step is to check the output voltage. 1223 just tells you you're hitting a limit, not which limit you're hitting. Clip a voltmeter to the sensor connector (with it still connected to the harness) and measure voltage. Should bounce between 0.2-0.8V. If it sticks <0.2V when CEL comes on you're lean, >0.8V you're rich. Knowing this is a big help with troubleshooting.

Also verify that you have 12V on the heater connector to the sensor while you're in there.
 

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Discussion Starter #20 (Edited)
Awesome, thanks - going after O2 testing next...

Air pump does its 90-second thing on start-up and no leaks detected around the EGR.

What would be a good test for the EGR itself?

What sources do we have for new EGRs if needed? (This one has a hairline crack, but away from the hole. It is sealed, but who knows - would be nice to replace it and feel good about it.

Also, I used an NTK generic O2 sensor some time ago and it worked great on another car... Never kept the box though! Cheap option too - anybody have that number please? Is it a 3-wire or a 4-wire O2 sensor on the 24 valve models?
 
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