2004 c5 hdi 110 cooling fan woes and now not running....

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citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Relay 1508...

I'm not with the car at the moment..

wheeler
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by wheeler »

The reg will do if you know that.

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Kb04 uyt..

wheeler
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by wheeler »

Out of curiosity Have you checked the maxi fuses underneath the under bonnet fuse box?
Looks like relay 1508 links to the under bonnet fuse box so if anything has popped i would suspect that rather than the ECU.
Here is the injection diagram. Fuel pump is 1211.
Attachments
RHZ Injection.jpg

MGmike
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by MGmike »

OK, I've been studying these diagrams for a number of hours now and I can't see any reason why shorting pins 1&3 on 1508 would upset the fuel pump circuit. Except.... just possibly a shared relay in the BSM! But that doesn't explain how the pump runs for the initial priming!
This is going to be a nightmare to diagnose remotely but I'm up for the challenge if you are? It'll be a long step by step process while I work through the wiring testing and checking points. I can't give you a list of checks to do as its a case of if this happen go here, if not go elsewhere as one result either way will dictate where to go next.

You need to concentrate on the fuel pump circuit first and when that's fixed, we can go back to the Fan circuit. By all means check MF1 as wheeler suggests just to be sure it's okay but I think that only provides power to the fan.

First thing I need to work out is where the pump supply comes from during Priming and what changes after the engine starts! To do this we need to eliminate the possibility of a second supply to the pump in the prime phase. To do that, we remove the primary source of power and see what happens! Therefore, Could you pull the pump fuse (I think it's F2 in the engine fuse box but check your handbook as the diagram isn't clear enough to read) and confirm if the pump still primes?

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Im gonna go out to it now.. But it's hot and I can't a do a lot in one go..

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

OK F2 removed.. No fuel pump prime.

Hell Razor5543
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by Hell Razor5543 »

Good luck with this, Paul.

I sent you an email re the DVDs I gave you. If we can get them working it might be helpful for you.
Last edited by Hell Razor5543 on 19 Jul 2021, 11:23, edited 1 time in total.

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Thanks James.. I'll nail it one way or another..

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Im sure I've got a working spare bsi in the container I've taken this one off the car and opened it.. There's no smell of any burnt components.. I'll fetch the other bsm and see if the car starts and runs with it. That will save us a lot of head scratching.

wheeler
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by wheeler »

Forgetting what we know has previously been to the car for just now, if i was looking at this as a fresh non start issue where the fuel pump primes but will not operate when the engine is turning the first place I would be looking is the crank sensor. With the exception of initial priming the fuel pump should not be powered unless the engine is actually turning for safety, it gets this info from the crank sensor so before going any further I would check live data to confirm the ECU can see a good engine RPM.
I know the chances are the non start issue has been caused by checking the fan issue but dont completely rule out a coincidence.

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

It primes.. It actually starts on the fuel that's primed up then it stalls as the fuel pump hasn't kicked back in.. Or switched back on so to say. I have recovered another bsm from my. Container and will stick it on to see what happens .. If the car runs then I know I have a bsm issue. The bsm I have was off a 2.0 8v hdi.. But the front wiper control had packed. Up in it. But if the car RUNS I can rule out Anything else as it will prove its the bsm.

citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by citroenxm »

Update.. It is NOT THE BSM at fault. I have fitted another one.. And its dooing the same thing. So it's something else or it is the main ecu at fault.

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Paul-R
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by Paul-R »

This sounds similar to a problem we had on our 2001 Xsara some eight to ten years ago. The engine would run for a second or two on starting up and then stop. I think it is a safety mechanism to only supply power to the lift pump for a few seconds to get the engine going and then something (the engine ECU?) issues a command to keep the pump supplied with power. This obviously wasn't happening. I checked the wiring from the fusebox to the pump by supplying a temporary 12v directly from the battery (take the fuse out first - you don't want 12v being injected backwards into the BSM or BSI) and the engine ran just fine.

I failed to find the ultimate cause of the problem so bypassed it by setting up a fused relay to supply power into the fusebox connection to the pump where the fuse used to be. I switched this relay on by taking a signal from one of the other fuses that were switched on and off by the ignition. On the Xsara there was an inertia switch and, as a safety precaution, left that in the circuit. Your car may not have one.

This was still working when we sold the car four years ago.

MGmike
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by MGmike »

citroenxm wrote:
19 Jul 2021, 11:18
OK F2 removed.. No fuel pump prime.
Ok, good. That confirms at least two of the relays in the BSM are working.

Question now is how does the ECU tell The BSM the engine is running...?
It could be via the CAN but I think its more likely to be a direct connection so as not to be effected by spurious CAN messages. The only wires that looks like an ECU control connection are on the BSM Black plug pins 3 &15.

Could you measure the voltage on these pins before and after the engine stalls?