Peugeot 206 cold start problem

I have a Peugeot 206 2003 1.4l and im having this problem for a long time.
at cold start when I start the engine it immediately stalls, when its not too cold outside it will start at the second time or third, and then the engine will stutterer for a few minutes, the engine idles for about 10 minutes and then everything kind of fine.
If I try to drive immediately, the gas response is very delayed and not accurate, so i must wait for about 10 minutes at cold start. otherwise i will have hard time driving, after the 10 minutes the gas response is not 100% accurate, but still driveble. (im used to it…)
in the winter, its very hard to start the enigne, its the same but I need to try about 5, 6 times till it will start…
important to say that the car is using too much fuel than it should, and has power loss…

Im having this problem for a long time and its driving me crazy, i have replaced the 3 sensor that are near the throttle body, replaced 2 lambda sensors, spark plugs and igniton coils. coolant temperature has been replaced as well.
when scanning with peugeot scan tool, it finds 4 errors which i will show in the pictrue.
what can i possibly do to find this damn problem? I have been in several garages, no one could find any problem…
the only thing that i can replace now is the injectors, but since its very expensive to buy, i dont want to spend anymore money before being sure what the problem is.

here is the picture from the scanning tool:

if can someone help me i will appriciate that a lot…

I’d guess you have a wiring issue with your oxygen sensors and idle stepper motor. Start be finding the ground (earth) connections on the harness and clean them up. They may be on the engine or run back to the body.

Check the oxygen sensor wiring for burns and pinches. Same for the throttle body stepper motor.

Injectors won’t fix the problem. The problem
are bad signals to and from those sensors

I did checked everything seemed to look ok, i cleaned them as well…

Have you ever done a fuel pressure test and to see if you have a stuck injector or valve in the pump. On a cold start, the engine is in open loop meaning it is only using pre programmed data from the computer and things like the stepper motor, engine temp sensor, etc. to set the fuel ratio. One the enginevwarms up it goes into closed loop and uses readings from to o2 and other sensors to regulate the fuel ratio. Your problem is with the initial readings before closed loop. You likely need a new mechanic that can check the cold temp readings and fuel pressure to see what is out of range of where it should be. I’m not a mechanic, but not everyone at a dealer is either.

I would add to see the diagnostic chart in the service manual for extended cold start, stalling, stumbling.

imo, no experience w/your car, just a driveway diy’er, it appears you have two separate problems. First is with upstream o2 sensor circuit. Second is with the throttle valve control. Suggest to start w/the first one. Ask someone who has electronics experience to trace the circuit, using a volt-ohm meter, point by point, until they discover what is causing the short to battery positive. the second problem is likely caused by a gunk deposit in the throttle valve area. May have to remove throttle body to clean it effectively. Could be a wiring/connector/pcm problem too, but removing the throttle body gunk is where to start.

If you continue to have drivability symptoms after fixing the upstream o2 circuit, next step for that would be a fuel trim test.

Well, i have already checked fuel pressure in cold and warm start, everything was as it should, i have cleaned the throttle body as well.
the thing is i cant find anyone that can find the problem, i have went to so many places and no one is able to figure it out, i dont know what they cheked but i dont think they even tried.
its all me now, and i dont know how to check everything but only to replace…
but since replacing things is not a solution here, what can i do?
as i uderstand from you guys there is a electric problem somewhere, but how can i find it if i dont have the knowledge…?

If you post the appropriate section of the wiring schematic, folks here will likely chime in w/some ideas how to trace out & test the o2 sensor circuits. If you have no way to obtain the wiring schematics, or haven’t yet learned how to use an ohm/volt meter, I’m afraid there’s not much chance of success on your own.

If you want to learn electronic testing as a future diy’er project, suggest to start by learning how to use an ohm/volt meter to trace a circuit. Likely several internet sites exist which will provide the needed training in conjunction with the meter’s owner manual for using the meter. There’s probably other sites that will train you on how to interpret automobile wiring schematics .

Another idea, I think there’s a book published titled “Electronics for Dummies” which would provide a pretty good introduction to the topic.

Just to reiterate, how does an o2 sensor cause a cold start problem? It’s been a while so maybe I’m wrong. Seems to me though a bad cam sensor might because on cranking it would look for the cam input and seeing none substitute for it. Then again maybe the crank sensor. Should have a code but I never got one.

One caveat I suppose is if a bad o2 caused a low or high fuel trim that would be used for starting but that should be noticed after closed loop.

Teach yourself what you need to know to fix it.

Start by going to the O2 sensor and follow the wires back to the ECU. Hard? Yes, but it doesn’t take a lot of knowledge to do that, does it?

Trace the wires from the throttle body. Unwrap the harness a bit if you need to. But all the sensor wire go back to the ECU. You are looking for damage and that doesn’t take a lot of knowlege.

It won’t fix itself so you need to do it.

I do have a little knowledge, i know how electricity works and i do know how to use volt meter but how sensors work and how much voltage they need is something that i dont know, i will try tho.
for now just to follow the wires to the ecu and check how much volt they got?
i will do anything that needed, i just need a little help explaining what to do.

There’s two basic types of O2 sensors. The most basic type doesn’t require an input voltage. That type produces its own output voltage just by a chemical reaction it has with any O2 in the exhaust gasses. This type requires the sensor be heated for the reaction to take place. In some car designs (older models for the most part) the heat just comes from the running engine heating the exhaust gasses. In other designs (newer cars) the O2 sensor has an electric-heater attached, and electricity from the battery heats the sensor. This method works better for emissions purposes b/c it allows the drivetrain computer to meter out the fuel more accurately sooner in the drive. There’s obviously more sensor wires needed for the electrical heater type. Voltage outputs from this type of sensor tends to be in the 0 to 1.0 volt range as I recall. Google will tell you more.

The other type of O2 sensor is called “broad-band”. Googling will provide some info on how that one works. No personal experience w/that type, but I think it uses an electrical heater system too.

I expect this problem will prove quite difficult to solve without access to the car’s wiring diagram.

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good to know, its been raining here for some time now so im waiting for it to end so i will be able to go out and check all of those things, I will check on google before doing anything and if i ran to some problems i will ask you guys for help. hope i can find the problem soon…

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