Xsara 1.4i injection light dashboard

[rvca]

Hello everybody.

I've been struggling with a problem for about a week now and I can't solve it.
I have an Xsara 1.4i that about a week ago started to turn on the injection light on the dashboard. When the light is on, the car idles irregularly and it almost looks like it is running with one less cylinder.
The strangest thing is that the problem is intermittent, the light comes on for a few minutes, then it goes out and the car starts working normally.. after a few minutes it comes back on and it's a cycle.

I've already tested practically all the sensors that influence the calculation of air/petrol by the ECU because I have another similar car and I just replaced the sensors one by one. I just haven't tested the lambda sensor.

I also tested the fuel pump and it is fine.

When passing the scanner, I see that whenever the light turns on I have the message "Open loop due to system failure".

Any idea what it could be?

It almost looks like an electrical problem to me.. but honestly I don't see where...

Thanks

[wheeler]

First thing that springs to mind is the ignition coil pack, very common failure on these cars, they can sometimes start as an intermittent failure like this, ideally you want to get some spark testers in to see if its sparking when the fault occurs.

[rvca]

thank you very much for the suggestion Wheeler.
I've already tested it.. and unfortunately that's not the problem either.
Normally the car starts normally, but after a few minutes the light turns on and starts to fail.. after some more minutos, it turns off the light again and works normally again.. then it turns on again and so on...

[rvca]

I noticed today that when the light comes on, just turning the steering wheel and activating the power steering or turning on the lights or the heating makes the rotations go down and it seems that there is a power failure

[rvca]

Yesterday I also detected a normal amount of water in the exhaust muffler..
there is no lack of water in the reservoir and the level is normal.
can there be some connection?

[rvca]

Finaly with a good car scanner i get the following errors:
P0200
P0440
P0110
P0115
injector.. evap.. iat.. ect??!!
Any ideas?

[rvca]

Despite the lack of answers, I still think that the forums serve above all for the exchange of ideas and learning.. So I will continue the topic until I find the solution.
I was able to identify a defective actuator and one valve. Replaced, but unfortunately the problem persists. idle control valve and evap canister purge valve.
After the replacement I erased the errors with an elm327 app and scanner that I don't know if it actually erases the errors recorded in the ECU, but i think yes.
When the car is completely cold, it works normally (open loop), without failures, and after a few (few) minutes (closed loop) the injection light turns on and starts to fail.
The fact that it doesn't fail with open loop makes me sure that the coil, spark plugs and injectors are in perfect health, correct?
In the scanner the TPS values ??are 13 with the throttle closed (without touching the throttle) and 75 with the throttle fully open (throttle pressed to the maximum)
Are these values ??normal for this engine?
Thanks

[ozvtr]

What are the 6th, 7th and 8th characters in your VIN? Is it a TU3 engine? Are you swapping parts from your C3? Does that have the same engine?

[rvca]

Thank you very much for the reply ozvtr.
The characters are "KFW".
I only swapped a few parts that had the same reference. MAP sensor and ignition coil.
Thanks

[ozvtr]

Some of the OBDII codes are generic and may not apply. That is, the descriptions may not reflect what's happening.

The P0440 is an “evap” error. The only Evap system monitored on the TU3 is the purge valve, the rust/brown cylindrical object on the top of the engine.
P0200 is a fuel injector error. Open circuit or short circuit.
P0110 is the air intake temp sensor error. This is part of the MAP sensor on the front of the inlet plenum, the bulbus object behind the throttle body and above the inlet manifold.
P0115 is a coolant temp sensor failure. The green sensor on the thermostat housing near the top radiator hose.

It seems the engine is not going into “closed loop” mode. That is, it’s not going into a mode where it reads the sensors and adjusts the engine parameters. Probably because it cant read the engine coolant temperature. That’s the main trigger to go into closed loop.

It’s possible that they are independent faults but I doubt it. My best guess is corrosion on the electrical connectors of the engine ECU.
Undo the 3 connectors on the engine ECU and look for corrosion on the pins.

[rvca]

Thank you very much once again for the ozvtr.
I've already tested the coolant temperature sensor with a multimeter and it's working without problem.
Previously, I had already checked the ECU connectors and I don't think there is a problem with corrosion either. But I will check again.
In fact, the engine goes into closed loop mode, but for a very short period of time. Connected to the scanner, maybe within a minute of starting the engine the engine goes into closed loop (closed loop using oxygen sensor feedback to determine fuel mix)
Stay in closed loop maybe another minute and go back to open loop (system failure)
I wonder if it will be worth testing spark plugs, ignition coil and injectors, since in cold open loop and before the injection light comes on, the engine works very well.
It should be noted that from the moment the injection light comes on, it is as if the car only works with 3 cylinders.
Yesterday I tested the Sensor MAP with the multimeter and with the ignition key on and engine off, I got 3.96V on pin 1 (MAP sensor signal), 5v on pin 2 (Power) and 2.46v on pin 3 (ACT signal) . Pin 4 (Negative)
With the engine idling pin 1 I got 1.9v, on pin 2 I got 5v and on pin 3 I got 2.5v. Shouldn't the values ??with the engine off be lower?
I also thought about the possibility of a problem with the fuel pressure regulator. Could it cause this problem? Some way to test it mounted in place? There is a sensor of fuel pressure in this engine?
Thanks again

[ozvtr]

First up you are not getting a “misfire” code. Meaning that the engine ECU thinks it's firing on all of the cylinders, despite it running rough. So (on the surface) it’s not related to spark or fuel supply. Now, never-say-never, but for the point of the exercise we will assume they are working.
The injector code is a problem but again no misfire code. Strange.
The concern I have is that you are getting all of these (apparently) unrelated faults at the same time. The chance that all of the sensors are failing is unimaginable.
I would recommend clearing ALL of the fault codes and wait until the engine fails again and see what codes pop up. If they all pop up again at the same time, I would suspect the engine ECU, wiring or something other than the sensors/actuators themselves.
Some codes can follow on from a single fault. For example a fuel injector failure might give an injector code and a misfire code. But your faults are not “related”. Now I put that in quotes because an ECU or wiring fault may cause your problem and not be a logical follow-on cause of another fault. As I said never-say-never. It could be anything BUT you have to start somewhere!
My assumption is that all the faults are related to an ECU or wiring fault. 1) it’s intermittent. 2) more than 1 fault at the same time. Of course, I can (and quite often am) wrong, but as I said, you need to start somewhere.
So clear the faults and see if they all come back at the same time.

No. There is no fuel pressure sensor. In fact there aren't many sensors on the engine at all, just enough to do the job. IMHO less things to break, confuse the engine ECU or mislead you in diagnostics!

[rvca]

ozvtr... thanks again for the reply.
I understand and agree, but I've seen all the wires and contacts in the ECU and I can't find any trace of corrosion. Everything looks like new to me. Even so, I applied a contact cleaner spray on all the ECU plugs.
There is a pattern..
With the cold engine, it starts without any problem (open loop), without any failure.. after one or two minutes it goes into closed loop.. and after another minute or two it goes back into open loop due to system failure.
If I wait a while and start the car again, it starts again without any problems.. The question is: It starts normally because the temperature has dropped (Tested already the coolant temperature sensor and is it ok)? Because the pressure in the fuel system changes (i already swapped the pressure fuel regulator) ? I can not realize..
It should be noted that even when the engine fails and the injection light comes on, I can still read the data from all the sensors in the scanner.. which leads me to believe that everything is fine with the ECU and possibly with the wires.. or not. ?
The recorded errors cannot be erased. I only have an elm 327 and I've tested it with several apps. I erase the errors.. if I rescan.. they are still there..
It should also be noted that I still see a lot of water coming out of the exhaust.. which makes me think that the catalyst is healthy and doing its job.. and the mixture is quite rich. There is no balanced combustion and unburned gasoline passes through the catalyst...
I will see the wires again and the spark plugs.. and may be the injectors.
Just a note.. after the engine warms up a little, goes from open loop to working well, goes to closed loop with the engine completely failing, and goes back to open loop due to system failure, the engine continues to work as if it had working with 3 cylinders only.
I'm going crazy with this

[ozvtr]

With the cold engine, it starts without any problem (open loop), without any failure.. after one or two minutes it goes into closed loop.. and after another minute or two it goes back into open loop due to system failure.
If I wait a while and start the car again, it starts again without any problems.. The question is: It starts normally because the temperature has dropped (Tested already the coolant temperature sensor and is it ok)? Because the pressure in the fuel system changes (i already swapped the pressure fuel regulator) ? I can not realize..
It should be noted that even when the engine fails and the injection light comes on, I can still read the data from all the sensors in the scanner.. which leads me to believe that everything is fine with the ECU and possibly with the wires.. or not. ?

The fuel pressure is not controlled by the engine ECU. The engine ECU only turns the fuel pump on and off. There is a mechanical pressure regulator in the fuel pump.
The engine ECU's are very reliable and tend not to be a failure point, BUT you cant discount it altogether. The wiring is another story. Damaged wiring is always a possibility!

The recorded errors cannot be erased. I only have an elm 327 and I've tested it with several apps. I erase the errors.. if I rescan.. they are still there..

Time to get a better sanner?

It should also be noted that I still see a lot of water coming out of the exhaust.. which makes me think that the catalyst is healthy and doing its job.. and the mixture is quite rich. There is no balanced combustion and unburned gasoline passes through the catalyst...

As long as there is oxygen coming through the exhaust system the converter will burn all the residual fuel. Meaning if the mixture is very rich, the converter will glow red while it is burning up the fuel!! If your converter is only about as hot as the rest of the exhaust system, the fuel mixture is OK. On your scanner you should be able to monitor the "raw" down stream O2 sensor data. It should be steady at about 0.45V. This part of the system only monitors the efficiency of the converter and plays absolutely no part in the running of the engine.

Just a note.. after the engine warms up a little, goes from open loop to working well, goes to closed loop with the engine completely failing, and goes back to open loop due to system failure, the engine continues to work as if it had working with 3 cylinders only.

Try removing the coolant temp sensor from the C3 and plugging it into the Xsara BUT don't replace the one in the Xsara! Just plug the sensor from the C3 into the Xsara loom! The engine ECU will be reading air temperature not coolant temperature now. It shouldn't go into closed loop, it should stay in open loop. See how the car runs.

Can you monitor "raw" O2 data on your scan tool? See what the raw data for the "upstream" or pre-cat O2 sensor looks like. Look at it before and after swapping the coolant temp sensors.

List which sensors you have swapped from the C3 to the Xsara, please.

[rvca]

Thanks again for the help ozvtr
It's definitely time to buy a better scanner. hehe..
I removed the c3 coolant temperature sensor and plug it to the xsara loom. I didn't remove the xsara sensor and the c3 sensor was measuring a constant temperature of 23º.
With the ignition on and the engine off, the pre-catalyst o2 sensor has a voltage of 0.45v, just like the post-catalyst sensor.

With the engine on (idle during all tests), and although the coolant temperature sensor remains stable measuring the air temperature, the engine goes to closed loop after 1 or 2 minutes. I notice the idle more stable, a little high, possibly the ECU is compensating for the low temperature.
The pre cat o2 sensor oscillates between 0.09v and 0.84v (what i think is good) and the sensor 02 post catalyst oscillates between 0.44 and 0.69v (may be not so good).
after a couple of minutes the injection light comes on (open loop due to system failure) and the values ??obtained from the pre-catalyst o2 sensor reading are between 0.11v and 0.12v and the post-catalyst o2 sensor remains stable at 0, 13v.
When the light goes off again and the engine goes back into closed loop, the pre-cat o2 sensor returns to values ??between 0.09v and 0.84v and the post-cat o2 sensor remains at 0.8v.. after a few minutes 0.3v. .. Strange.. I can't even understand these values.
I understand that with the light on I realize that the mixture is poor.. but why??

Other data that may help to understand what is going on

With the ignition on and the engine off:
Load: 76%
Vacuum: 1.3
Tps: 13%
Intake manifold absolute pressure: 97.0 Kpa
Timing advance: 64th

With the engine at idle:
Load: 35%
Vacuum: 1.3
Tps: 13%
Intake manifold absolute pressure: 45.0 Ka
Timing advance: between 4.5º and 7.5º

The sensors other gear that I swapped with the c3 earlier were:
Ignition coil, tps sensor, purge valve, map sensor and iddle regulator

Thanks again