Peugeot 406 2.0 HDI 90HP, cold start problem

[frog]

It what you're saying also available on the Siemens inection? From my understanding, those solving are for the Bosch injection.

Yes the links i'm referring to show the Bosch injection pump (i have experience with). Siemens pump i have no experience with, but it seems to have also a pressure regulator. I'm not sure if it has a "third piston deactivator".

[frog]

Here is an image i found browsing the internet:

5WS40018-Z.jpg

(162.29 KiB) Not downloaded yet

Maybe check also the electrical wiring to the "Pressure Control Valve (PCV)" and the "Volume Control Valve (VCV)"

Again, just my 2 cents...

[Doggy]

The rough running and white smoke on starting could be glow plug related.
Normally a HDi will start easily without waiting for the glowplugs, but that's at UK temperatures, may be needed when it's colder.
Also the plugs stay on for some time after starting, 30 seconds or so to aid initial smooth running.
(Note the warning light does NOT tell you when the plugs are energised, it's to tell you to wait before starting the engine).

Are you sure the glow plugs are drawing power, (can you check with an ammeter)?

[AndreiNCS]

The rough running and white smoke on starting could be glow plug related.
Normally a HDi will start easily without waiting for the glowplugs, but that's at UK temperatures, may be needed when it's colder.
Also the plugs stay on for some time after starting, 30 seconds or so to aid initial smooth running.
(Note the warning light does NOT tell you when the plugs are energised, it's to tell you to wait before starting the engine).

Are you sure the glow plugs are drawing power, (can you check with an ammeter)?

Hi, Doggy


The glow plugs are working fine, I just replace them 2 months ago. So does the relay for them. A test was performed and everything works as it should on the electricity circuit, from the battery to the glow plugs.

[AndreiNCS]

Here is an image i found browsing the internet:



5WS40018-Z.jpg

Maybe check also the electrical wiring to the "Pressure Control Valve (PCV)" and the "Volume Control Valve (VCV)"

Again, just my 2 cents...

Thanks for this informationa but sadly, it's not from the injection pump. As I said early, I try 2 pumps and the car starts the same.

[GingerMagic]

Hmm, I'm out of ideas - sorry.
Maybe you could clean the crank sensor (brown plug on top of gearbox) and also clean the cam sensor (top left of engine, hidden under the injector wires) which could help and won't cost any money.....
There is also a fuel pressure sensor on the back of the pump, this can get a bit blocked with dirt - it can be removed and cleaned also. I cannot be sure if the Siemens pump has one though.
How is your battery?
Maybe try a jump start in the morning even if the battery is good..?

Your English is very good, no need to apologise.

[AndreiNCS]

Hmm, I'm out of ideas - sorry.
Maybe you could clean the crank sensor (brown plug on top of gearbox) and also clean the cam sensor (top left of engine, hidden under the injector wires) which could help and won't cost any money.....
There is also a fuel pressure sensor on the back of the pump, this can get a bit blocked with dirt - it can be removed and cleaned also. I cannot be sure if the Siemens pump has one though.
How is your battery?
Maybe try a jump start in the morning even if the battery is good..?

Your English is very good, no need to apologise.

I will try by cleaning those sensors. What do you mean by "jump start" ? Meanwhile, I disconnect the coolant temp sensor, I start the engine ( starts relative well because the car sets the temperature to -18 C degrees as far as I know, and the glow plugs remain on for like 10 seconds, but still a lot of smoke after starting) and after that I reconnect the coolant temp sonsor.

P.S. Battery is good. It was almost new when this starting problem showed up, about 3 years ago, and since then, I have the same battery and sadly, the same problem.

[frog]

Meanwhile, I disconnect the coolant temp sensor, I start the engine ( starts relative well ...

That would indeed indicate that the fuel system is ok, it can deliver enough fuel.

At cold temperature, the fuel-air mixture must be very rich. By disconnecting the coolant temp, the ECU thinks it is very cold and maximises the fuel injection. Which apparently works fine if you say it starts relative well.

Apparently, the "hardware" (fuel pump, injectors) has no problem suppyling enough fuel. Maybe the problem is on the other side: too much air. That can be caused by a stuck-open EGR valve. Did you check that? You might want to insert an "EGR blanking plate" to make sure no false air is entering the system. Have a look here: http://www.406oc.co.uk/viewtopic.php?f= ... 78#p232721 .

For the ECU to be able to automatically choose the correct fuel-air mixture, it is very reliant on sensor data. As Gingermagic suggests, check all the sensors. You have PP2000 software? It is very convenient to read out the sensor values to be sure they make sense.

[AndreiNCS]

Meanwhile, I disconnect the coolant temp sensor, I start the engine ( starts relative well ...

That would indeed indicate that the fuel system is ok, it can deliver enough fuel.

At cold temperature, the fuel-air mixture must be very rich. By disconnecting the coolant temp, the ECU thinks it is very cold and maximises the fuel injection. Which apparently works fine if you say it starts relative well.

Apparently, the "hardware" (fuel pump, injectors) has no problem suppyling enough fuel. Maybe the problem is on the other side: too much air. That can be caused by a stuck-open EGR valve. Did you check that? You might want to insert an "EGR blaking plate" to make sure no false air is entering the system. Have a look here: http://www.406oc.co.uk/viewtopic.php?f= ... 78#p232721 .

For the ECU to be able to automatically choose the correct fuel-air mixture, it is very reliant on sensor data. As Gingermagic suggests, check all the sensors. You have PP2000 software? It is very convenient to read out the sensor values to be sure they make sense.

From your experience, it's there any change that the problem could be related to ECU? Someone said that could be from charging the battery with a robot and transmitting parasitic signal to ECU.... Anyway, thanks for your infos, I will check the EGR valve.

[frog]

From your experience, it's there any change that the problem could be related to ECU? Someone said that could be from charging the battery with a robot and transmitting parasitic signal to ECU.... Anyway, thanks for your infos, I will check the EGR valve.

No, that is not my experience. The ECU is in my experience very robust and reliable (mine is Bosch, but i expect the same is true for Siemens). The ECU can behave strange if its sensors give strange values. Or better formulated: the ECU falls back to "best guess" defaults if it sees that a sensor gives invalid or incoherent data.

There is a lot of very smart software in the ECU which is checking and validating the sensor input data. You can read the findings of that validation software with PP2000. Note that most of the "strange things" which the ECU can see are not shown in the car dash or LCD screen. But PP2000 does show them.

[AndreiNCS]

From your experience, it's there any change that the problem could be related to ECU? Someone said that could be from charging the battery with a robot and transmitting parasitic signal to ECU.... Anyway, thanks for your infos, I will check the EGR valve.

No, that is not my experience. The ECU is in my experience very robust and reliable (mine is Bosch, but i expect the same is true for Siemens). The ECU can behave strange if its sensors give strange values. Or better formulated: the ECU falls back to "best guess" defaults if it sees that a sensor gives invalid or incoherent data.

There is a lot of very smart software in the ECU which is checking and validating the sensor input data. You can read the findings of that validation software with PP2000. Note that most of the "strange things" which the ECU can see are not shown in the car dash or LCD screen. But PP2000 does show them.

Got it! Thank you very much!
Do you know if from the coolant temp sensor, to the ECU, is there any other element on the ciruit or they're conected just by a wire?

Does anyone have an electical diagram for this model of Peugeot?

[steve_earwig]

There's a few of us on here with Sedre (wiring diagram database) but we're going to need to know a bit more about your car. Can you post your car's build code or, even better, your chassis number?

[AndreiNCS]

There's a few of us on here with Sedre (wiring diagram database) but we're going to need to know a bit more about your car. Can you post your car's build code or, even better, your chassis number?

It's an Peugeot 406 2.0 HDI 90HP, the one with RHY (Siemens Injection) on the chassis number. Thanks in advance!

[frog]

For SEDRE, it is best if you give the DAM number. It is on a sticker attached close to the hinge on the drivers door - see pictures 11 & 12 on http://www.peugeotforums.com/forums/141248-post3.html

[steve_earwig]

Not to worry, I found some time and there doesn't appear to be anything between the temperature sensor and the ecu. This is trying a few DAMs between 9001 and 9999 (I don't think there were any Siemens before that) so I think it's safe.