What do these mean?
 

Went to garage the have a diagnosis test.
Four things came up.
1) Barometric Pressure
2)Rail Pressure
3)Glow Plug
4)Can or Cam Message

Numbers 2,3 and 4 were cleared and didn't return but number 1 was ' in the ECU' and couldn't be moved

What do all these mean and what do they do?
Please tell me if you know.

Barometric pressure is the ambient air pressure. There is a sensor inside the diesel ECM that measures it.

Rail pressure is the HP pump fuel pressure measured by a sensor that sits on the end of the common rail - all the injectors are fed with fuel from the common rail.

Glow plug - common fault on just about every diesel Rover 75 - I'd be more surprised if you didn't see it. The glow plugs heat the air in the cylinders for starting in cold weather, but with the higher fuel injection pressures that common rail systems offer glow plugs aren't needed unless the temperature drops well below zero.

CAN message - the Controller Area Network is a high speed bus communication system that communicates information between some of the ECUs. The other main bus system is the K-Bus. The IPK can translate between the two.

If you are getting a CAN bus fault then it could be your ECM has gone for a swim at some point and needs repairing or replacing.










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Just one thing Mike. I believe the injectors fire a mist of diesel directly onto the glowing tip of the glow plug thus making the fuel easier to ignite.--:shrug:

Maybe on some engines Jon, but it doesn't look like they do on the M47R. The injectors are central on the top of the cylinder and spray fuel directly into the combustion bowl in the piston crown, whilst the glow plugs are on the inlet side of the cylinder head, between the tangential inlet ports and swirl inlet ports.

Scrapped my old cylinder head so can't check though, but I don't remember the glowplugs protruding very far at all. At top dead centre there isn't much in the way of clearance between the pistons and cylinder head!

I didnt think any diesels did this, as I thought they all ignited from.heat generated.by compression. Would be Interesting to.know what engines did this. I would.have thought this would have caused premature failure on a glow plug as well due to hot spots.

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Interesting but if they only needed compression to fire up it tends to negate the glow plugs.---:shrug::shrug::shrug:

I know the R75 diesel only needs plugs in very cold conditions when the fuel starts to turn to wax .

I no longer have the manual for my wife's Peugeot and maybe I got the idea from that about the glow plugs.

Must make a point on coming back about that.--;)

https://en.wikipedia.org/wiki/Glowplug

extract - the fuel injector spray pattern then impinges directly upon the hot tip of the glow plug during the injection of fuel at top dead center. This ignites the fuel even when the engine is insufficiently hot for normal operation, which reduces the cranking time to start the engine.

Learn something new each day (although this may not apply directly to our engines though? :shrug: I didnt know they operate like this, as I would have thought this would have created a point of failure on the tip of the glowplug.

I know our cars dont need them, an old Transit I drove for work, I dont think even had them - it didnt even have a glow plug light! But my dad's old escort van for his work wouldnt start until the light went out :shrug:

The amount of heat generated by compression would be quite a lot. Our engines turn over relatively quickly, compared to some, which is why ours generally do not need them.

It isn't the cranking speed but the higher fuel injection pressure that common rail systems can achieve that make for easier starting from cold without relying on the glow plugs. ;)

Our Op doesn't have a problem with glow plugs anyway. He hasn't come back but has asked a related question on a new thread so I'm bowing out. Looking at the fault codes, if it was me I'd have the ECM checked over by someone who knows what they are doing because it sounds like it is failing.