C5 Series 1 Won't Run

[jonhardy]

A couple of comments that may be useful : The earliest 16V Hdi's (early facelift C5, and 406 cpe UK, at least) had a pump in the tank and the engines had a belt driven fuel pump, not on the end of the camshaft as they later all did. These engines have an alloy inlet manifold, not black plastic.
And the simple way to settle the question re lift pump or not, is to look at the top of the tank : 4 wires implies fuel pump, 2 wires means gauge only. Or as a Peugeot mechanic said " if it has a primer up front, no pump down back".
Having had C5's for a while, there's a few "unfortunate events" I recall. At times when the 16V RERHRJ wouldn't start, cranking while working the squishy priming pump thingy always worked. Having the tank full helped, but trying to convince impoverished offspring of this was another matter.
The series 1 Hdi has only ever needed an Airflow Meter. China $26, made a huge difference.

 

[JAJEA]

John,

The easyist fix for this problem is probably to replace the BSM module with a known good one. The problem is most likely an intermittant relay in the BSM that connects the battery power to the fuel pump when the engine ECU thinks it is safe to flow fuel and tells the relay to make the contact.

Otherwise if you must keep this BSM, the best fix for is t fit an external relay that triggers fom the lead or CAN signal coming from the engine ECU and connects power from the correct power circuit to the fuel pump power lead. I'm starting to look at electrical diagrams but SEDRE is asking me about the brand of engine ECU the engine has.

Can you tell me what sort of engine ECU this engine has - Siemens, Sagem, Bosch or Magnet Marelli 

Ken, it is a Siemens unit as is the BSM assuming the BSM is the unit within the fuses and the 3 MTPs holder.

 

[Demannu]

That ECU is the auto trans controller. The engine ECU is below it, with the three plugs.

 

[seasink]

BVA (label) = boîte de vitesses automatique.

 

[JAJEA]

Thanks guys, it looked big enough to be the ECU.
Can I assume that the ECU will also be a Siemens or do I have to dig deeper?

 

[Demannu]

On an RHZ engine, I suspect it will be a Bosch.

 

[seasink]

 

[JAJEA]

OK, tomorrow I'll dig deeper.

 

[seasink]

Do these diagrams help? They are early c5 2.0 HDI 110 CV.

 

[JAJEA]

Do these diagrams help? They are early c5 2.0 HDI 110 CV.
View attachment 232327

It sure is a Bosch 281 011 524

John,

The easyist fix for this problem is probably to replace the BSM module with a known good one. The problem is most likely an intermittant relay in the BSM that connects the battery power to the fuel pump when the engine ECU thinks it is safe to flow fuel and tells the relay to make the contact.

Otherwise if you must keep this BSM, the best fix for is t fit an external relay that triggers fom the lead or CAN signal coming from the engine ECU and connects power from the correct power circuit to the fuel pump power lead. I'm starting to look at electrical diagrams but SEDRE is asking me about the brand of engine ECU the engine has.

Can you tell me what sort of engine ECU this engine has - Siemens, Sagem, Bosch or Magnetti Marelli?

Cheers, Ken

Ken it is certainly a Bosch ECU.
Leaving the BSM as is where is, I'd be happy to supply the pink pump cable (terminal 16 on that left black MTP) cable #1235 within the wiring diagram provided by seasick.
Where's that CAN lead for me to power the relay to get those 12Vs to that pink cable #1235 that powers the fuel pump.
John

 

[JAJEA]

Do these diagrams help? They are early c5 2.0 HDI 110 CV.
View attachment 232327

Beautiful wiring diagrams seasink. Thank you. Best I've come across. Nevertheless, not knowing the codes to what the components are makes it a bit difficult. Question, the hard wiring that ends up dashed, is that an indication that part of the "wiring" is within a circuit board?
John

 

[seasink]

The dashes are connections internal to the unit, inc on a board.

The component numbers are common to most PSA diagrams, but aren't listed in the stash of pdfs for that particular manual. I'll see if I can find a list - it might be from another model.

 

[Ken W]

The diagram from Seasink looks the same as the one I'm looking at. Wire 1235 does power the fuel pump but it connects to pin 11 on the black 16 way connector. Is F2 the fuse for the fuel pump? - if it is then that would be a test of the dotted line theory.

It looks to me that maybe wire 1223A that connects via pin 8 on the black 16 way connector controls the relay that powers the fuel pump.

So see if you are getting power to the fuel pump on pin 11 with the engine cranking and see if the line on pin 8 is being pulled down to ground or to less than one volt while the engine is cranking.

Cheers, Ken

 

[seasink]

Here is a component list for that engine - in Spanish! It's pdf, so translatable. The symbols and colours are explained too.

 

[dimistyle]

Ken, he also has a melted pin on the green MTP this might be a sign of another internal relay affecting the fuel pump operation?

 

[David S]

Seasink's diagram is what you find in SEDRE via your VIN. The same relay supplies fuses 2 and 15. If the relay is faulty, you won't get 12V at fuse F15 also. If you can rig up an alternative supply to the pump and confirm it runs reliably, then the fault is likely inside the engine slave / fuse box. The relays can burn the terminal inside or develop dry joints where they are fitted to the PCB.
The dashed wiring goes through the component to the other side, so F15 connects to pin 1 on the 16 pin (16V) black (NR) connector and supplies the oxygen sensor heater in the HDi model (Injectors, coils for Petrol). And F2 supplies pin 11 of the grey (GR) 16 way socket, supplying the tank fuel pump. It won't be the melted socket on the green (VE) socket. I'm not sure which pin that is.

 

[dimistyle]

Pin 1 Green your onto it, the melted pin, so some additional resistance may be causing the relay not to saturate or reducing current to F15 hence fuel pump not starting everytime.

I think I have a spare Green connector after I had a similar issue. And a spare wire with the larger terminal as had to chop off the burnt damaged offending wire.

 

[David S]

No, it's pin 11 of the green socket for F2. Fixed my typo. The melted pin isn't pin 11.
Edit: This is wrong - see my post further down.

 

[JAJEA]

No, it's pin 11 of the green socket for F2. Fixed my typo. The melted pin isn't pin 11.

The melted pin in the green MTP is numbered 16. The numbers are on the up side looking down on the male pins.

Power to the pump, is via the pink cable in black MTP.

I'll check again later that it is pink but pretty sure it is pink, attending to some medical issues currently.
John

 

[David S]

Sorry, I've misled you. I confused the sockets in the diagram and you want to look at the grey socket. GR=Gris=grey. VE=Vert=green.

The pin allocation for the grey socket has the pump fed from pin 11. Pin 12 is empty I expect for the HDi. I think pin 10 will have a wire connected already.

Grey socket:

Green socket. Melted pin 16 is listed as being for AC.

Black socket:

This is a portion of a relevant wiring diagram and you will see pins 8 and 16 on the green socket are joined and supply the cabin AC blower. It was common for the wiring to have a meltdown at the fan module end, but you have this issue at the BSM end. While it already has a relay in the BSM for this, since the pins are already damaged you may need to add another high current relay (F18 is a 40A fuse) into the line feeding the blower to reduce the current being drawn through pins 8 and 16.