Non-starting CSR ... problem and fix

[vertew]

Here's a problem / solution incident I thought I'd share for the record ...

My 2006 CSR has been a reliable beast in the three years I've had it (other than a misfire incident last summer).  But, last week at a friend's house, it wouldn't start.  Just spun the starter, but no firing. 

The problem turned out to be the inertia switch plug on the loom side.  The female spade sockets weren't making a tight connection and one looked a little cooked.  Once taken apart, cleaned, fettled and reinstalled, all was fine.  Though I've now ordered a replacement switch and connector sub-loom as it's such a critical part.

I know the inertia switch itself is high on the list of potential troublemakers, but worth adding its connector too when looking for faults.  A fair amount of current must flow here, so worth making sure that everything is clean and tight to avoid problems.

Makes me think that I may need to do complete engine loom replacement one day, perhaps not so many days away.  The car is 12 years old, which probably isn't particularly aged by 7 standards, but the there's an awful lot of heat and vibration generated with powerful Duratecs that must be tough on the wiring.

Here's a bit more of the story ...

At the time I was stranded, it was clear that the fuel pump wasn't priming when the starter spun.  I tried the usual things - power off/on via battery cut-off; press the inertia switch and check inertia plug; swap some relays in fuse box; good tap on the MFU box.

I even tried bridging the connection on the intertia switch loom plug with a piece of wire (thanks to Rob Morely at Rat Race for that suggestion) - which I now know should have worked.  Don't know why if didn't, perhaps I didn't to it properly, or the terminals sockets were in too poor a state.

Anyway, after 45 mins of the above, something I did worked.  When I tried the key, fuel pump primed and car started fine .... just as AA man turned up (15 mins after phone call - impressive).  So, I drove home deeply suspicious that nothing was fixed.  Sure enough, I wanted to go for a blat on the following Saturday and ... no fuel pump and no dice.

I put aside Sunday for a long session of 'testing the hell out of everything'.  I plugged in the laptop with easimap to see if any ECU faults were showing.  The only thing unusual was all injectors were being flagged as 'open' in the fault list.  This combined with the lack of fuel pump priming pointed even more strongly to an electrical problem.

I swapped in a spare MFU, which didn't help.  I was starting to think the immobiliser could be the culprit (horror), but thought I'd just check the inertia switch again as this would cause the same symptoms - no fuel and no injectors.  As above ... that was it.

cheers, Andrew.

[Rogercsr7]

Thanks for that info Andrew. I'll file that in the "need to know" category. Hoping to get through 2018 trouble free after last year's electrical hiccups returning from Portofino.

[vertew]

Thanks Roger - electrical gremlins are the worst but I'm pleased it wasn't the fuel pump .......