Xantia V6 No RPM Running

[addo]

Yep, as in "Elle ne va pas, m'sieur".

No dialogue with ECU. Plenty of dialogue with CPH and it is not getting a signal from the engine.

I'm starting to suspect fuse slave board under the dash has failed.

[Mandrake]

Pardon my (lack of) French, do you mean the tachometer is not working, or that its not running at all ? I'm guessing that latter.

Checked the power to the ECU yet ? You might find the following wiring diagrams helpful, its for my RPO7905 Xantia V6 Exclusive but is probably the same or very similar:

https://dl.dropboxusercontent.com/u/782 ... nciple.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... lation.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... Wiring.pdf" onclick="window.open(this.href);return false;

I have the MP7.0 ECU functional/descriptive pinouts in another document but I can't get at it from work, I can post it tonight if you like.

I know you love unravelling knots so this should get you started in the mean time.

[addo]

I don't think there was much change to the V6 wiring between Ph1 and facelift models. The ECU retained the same part number. I believe both the problem car and the donor have your relay setup.

The diagrams will come in handy. I'm going to play with unplugging fuses on a running one until I lose dialogue.

[Mandrake]

As promised here's the document with descriptions of the ECU pinouts, makes it a bit easier to understand the wiring diagram when you know the function of each pin...although some of them are in funny "translated French" so don't mean QUITE what they seem...

https://dl.dropboxusercontent.com/u/782 ... System.pdf" onclick="window.open(this.href);return false;

It looks like the permanent (memory) power feed comes from the battery to Fuse F14 in the drivers foot well fuse box and goes to pin 18 on the ECU connector.

The ignition key switched supply comes from the battery to Fuse F2 in the under bonnet fuse box, goes through one of the double injection relays to pin 27 on the ECU, and through the other double injection relay to pin 37 on the ECU.

By the way is there any life from the ECU at all ? Does the idle control valve vibrate constantly while the key is on as it should ? Can you measure the 5 volt reference on one of the TPS pins ?

BTW it is possible to back probe the ECU connector while its still plugged in. Fiddly but possible. Cut the cable tie on the rubber boot, roll the boot back on itself as far as you can, undo the two screws on the plastic clamp over the cable and the single screw at the other end then manoeuvre the connector out of its casing, (there's a rubber grommet to be removed too) there's just enough freedom to turn the casing 90 degrees so that you can shut the bonnet with the back still off the plug without unplugging it.

Some of the middle terminals are a bit hard to get at but most of them are accessible. That's how I measured the crank sensor and knock sensor signals on a live running engine.

[addo]

OK, update time.

First up, the engine harness that was swapped in with the donor was bodgy. The pinouts didn't match the main harness. Back went on the original harness; I now had dialogue. Still no fuel pump actuation with Lexia. OK, observe the disconnected inertia switch and connect/depress - I could now test the fuel pump relay...

The weird bit:

I tried two ECU/CPH sets with corresponding keys (and have become a whiz at getting the CPH out with only glovebox removal). Both times the Lexia shows the engine ECU as not responding. However I found exactly the same screen message on a running V6 facelift I had for comparison. Maybe someone else can try this on Lexia/Diagbox?

I think the car will now run, as it recognises the key, but won't know for a few days.

[Mandrake]

I tried two ECU/CPH sets with corresponding keys (and have become a whiz at getting the CPH out with only glovebox removal). Both times the Lexia shows the engine ECU as not responding. However I found exactly the same screen message on a running V6 facelift I had for comparison. Maybe someone else can try this on Lexia/Diagbox?

Where is it saying the engine ECU is not responding ?

Are you trying to go directly into the engine ECU and getting no communication with it ?

Or are you looking at the parameters measurement section in the CPH where it reports whether it (the CPH) has communication with the engine ECU ?

A screen shot of the error is worth 1000 words if you can take one...if I know exactly where to look I can check on mine.

[Mandrake]

I tried two ECU/CPH sets with corresponding keys (and have become a whiz at getting the CPH out with only glovebox removal).

If you get a chance could you provide some more details on CPH swapping in the below thread:

http://www.frenchcarforum.co.uk/forum/v ... 4&p=380691" onclick="window.open(this.href);return false;

[addo]

It's led me to one conclusion. The simplest way to stop your Xantia being stolen by a clued-in thief with spare ECU and CPH in their hands, is to lock the glovebox!

[Mandrake]

A really clued up thief would simply carry around a fully unlocked engine ECU - no need to do anything with the CPH then.

Break the window, disable the alarm, swap the engine ECU, hot wire the ignition key switch and away you go...somehow I don't think there are many thieves that interested in stealing a Xantia though

[CitroJim]

somehow I don't think there are many thieves that interested in stealing a Xantia though

No, most of them are locked up for the good of society Simon...

[Mandrake]

somehow I don't think there are many thieves that interested in stealing a Xantia though

No, most of them are locked up for the good of society Simon...

In a white padded room ?

[CitroJim]

In a white padded room ?

Yep, that's it

[addo]

It runs, poorly.

Sounded like a dropped spark so we whipped off the top manifold and improvised a ground tether to check each coil using the actuation menu in Lexia. A substitute coil pack and leads were found to spark OK.

Had three sets to test/play with. Lead resistances ranged from 6K to almost 900K. I think the ones over 10K could be considered faulty.

Hoping it all sorts out now upon reassembly.

[CitroJim]

It runs, poorly.

That'll be good to see this thread to at least 96 pages then Adam

[Mandrake]

It runs, poorly.

That'll be good to see this thread to at least 96 pages then Adam

It runs, poorly.

Sounded like a dropped spark so we whipped off the top manifold and improvised a ground tether to check each coil using the actuation menu in Lexia. A substitute coil pack and leads were found to spark OK.

For the rear bank outputs of the coils you can test them at the coil without removing the manifold...although that doesn't test the leads of course.

Had three sets to test/play with. Lead resistances ranged from 6K to almost 900K. I think the ones over 10K could be considered faulty.

My new spark plug leads measured between 5.5K and 6.5K - with the longer wires being slightly higher than the shorter ones, as you'd expect. Over 10K would indeed likely be faulty.

Try flexing the wire at the sharp bend near the cassette where the wires do a right angle turn and head towards the back of the manifold and then over the type - two of mine were broken there - 6K when you bend them one way, open circuit when you bend them slightly the other way!

Hoping it all sorts out now upon reassembly.

What was the condition of the spark plugs ? If they're been misfiring for a long time they could be pretty fouled...

Good luck! I hope you don't go through the same dramas as me, I'm pretty sure my remaining problems are all ignition misfire related, fixing the ignition system on mine seems to be like pressing down bubbles in wallpaper, when I fix problem number two problem number one rears its ugly head again...