[FIXED] CSR / Duratec 2.3: Intermittent engine 'cough' under load

[Piers300]

Great news it is fixed. I've been ready your posts and wondering when the issue was going to be found. I had a problem with my R300K not starting from cold that dragged on for three years, till a bad earth on the ECU was found. Anyway, delighted it is sorted.

Piers

[sjmmarsh]

Andrew

thanks for posting the pics - very clear, useful and an easy mod! I'll have a try, but it will be 12 months before I'll know it has worked (it is infrequent and hard to replicate). 

My voltage is marginal on tickover, but the two steves commented this was normal when they remapped mine. I haven't noticed any flickering of the ignition light, but every time my hiccup appears my attention is fully on the road ahead as I am overtaking. I don't have anything to monitor the bus though  

I did have a problem with the alternator wire breaking inside the alternator which gave an intermittent charge. Initial symptoms were the light barely flickering, but over about 300 miles it turned into a full failure, which made for an interesting journey home as it was night time and the engine would stall if the revs went below 2500. Not too bad until I got close to home and had to deal with traffic lights and sleeping residents!

Steve

[vertew]

@Elie boone - thanks, the belt looks like a pretty secure arrangement with a sprung tensioner, but the issue is fixed now (thank the stars).

@Piers - thanks and yes, intermittent faults are the worst.  Bad earth connections and vibrations have a lot to answer for ...

@Steve - yep, it's a 45min job, so definitely worth having a go.  Re. my voltages, they do look slightly higher and a bit more stable after the 'fix'.  Might be worth getting one of the MBE CAN USB leads just for the sheer geekery of gawping at a load of realtime data on what your engine is doing - and would be useful for any future fault finding.  I did spot your post on alternator wire tks.  I was convinced it was an alternator problem, which was an expensive guess.  At least I now have a spare.  Pity the neighbours.  If I'm going out for an early morning blat, I guiltily push the car to end of drive before starting and it still wakes the dead.

tks, Andrew.

[aerobod - near CYYC]

Glad you got it fixed, another good piece of diagnosis for those troubleshooting in the future.

[Jonathan Kay]

Well done: hope that's the end of it. Thanks for the details.

I'm fairly sure I've got a CC standard immobiliser (the CSRs were factory-build), but generally, the standard of immobiliser fitting is often not up to the standard of other electrics.  Others might want to check their immobiliser installations.

Is there anything special about the immobiliser or its mounting in these particular 7s?

Jonathan

PS: To absorb energy from vibration the optimal density of foam is often a lot higher than you might think.

[John Vine]

...picotech 2000 series...

Thanks for the pointer.  I'll investigate.

JV

 

[vertew]

Thanks again Jonathan, John Vine and aerobod (esp for the USB CAN recommendation).  Still basking in the glow of a satisfying glitch fix.  What a total PITA that was.

Jonathan - don't know whether there's anything different about the immobiliser / mounting on my CSR vs S3/SV.  I'd have thought probably not.  It's a 'Sterling Excel' by Scorpian.  The model still seems to be available - see here.   I had a peek inside the case and certainly looks like there's a lot of electronics going on rather than a dedicated chip, which might predispose to vibration issues.  I might take it apart and see if re-soldering components looks viable (though that's a bit of a high-risk activity).  I've not got any 'proper' vibration damping foam, so I just used some that I had around the garage, hopefully good enough.

I also noticed that my MBE ECU is hard mounted against the engine bay (with no vibration insulation) and the earth tabs were sitting on top of the mounting flanges, eg, butting up against the plastic case.  Can't be good practice.  So, I put some foam insulation under the ECU and moved the earth tabs down so they butt up against the bodywork.

It's now probably time to step away from the foam and get driving ...
tks Andrew.

[vertew]

The thread that won't die ...
Sorry, but thought it might be worth sharing a 'fatal attraction' moment.

Having fixed the misfire, I decided to give the 7 a celebratory deep clean + refresh the anti-corrosion wax.  When done, I took it our for a spin and ... a load of new and much more terrible misfires.  In fact, I was worried whether I'd make be able to make it home.  AWESOME!!

Other than lots of bad language, my initial reaction (fairly desperate) was that some water had got into the electrics.  I opened up + sprayed water dispersant into some of the more obvious connectors and left the car overnight, but .. it was no better the next day.

Putting aside thoughts of taking up a new hobby, I connected up the laptop + easimap and took the car out again.  Thankfully, the problem was obvious - Barometric Pressure was intermittently reading / not reading, coinciding with the misfires.  I checked under the bonnet, wiggled the MAP sensor cable and one of the wires simply fell out of the connector plug.  I took the plug apart, soldered the wire back to the pin, reassembled, tried the car and all was fine.  I did order a new OEM connector from simtek (huge stock of OEM automotive connectors + extremely helpful) in case the plug wasn't fixable, but it was.

Previously, Easimap had picked up a Baro sensor error.  I had come to the conclusion that this was 'normal' as Manifold and Baro pressure would be the same (car has no manifold) and Manifold Pressure was showing a value that ECU was using for atmospheeric pressure.  With the fixed MAP sensor loom connector, Baro Pressure is now reading correctly (see pic - bat AFR is normal and clears after few mins after start).  So it turns out that had been a hidden problem with the connector all along.

So was this part of the original misfire problem?  In the best traditions of nasty intermittent faults, who knows.  It does look like the MAP connector might be another casualty of vibration.  The loose wire looked 'necked' like a fatigue failure.  Big capacity in-line 4cyl engines generate a lot of vibration, which makes them a particularly hostile environment for anything attached to them, such as sensors and connectors.  Worth noting.

tks, Andrew.

[aerobod - near CYYC]

What I have done with the sensor connectors on my R400D that have enough slack is created a loop from where the wires exit the connector, back to the body of the same connector and then used a tie wrap to hold the wire against the connector. Any vibration of the wire should then be away from the crimp or solder joint stress point.

[JNC]

When my Duratec .was remapped by the two Steves they asked if I was likely to drive the car at high altitude I told them no so they turned it off they said it was a pice of #### and was always failing !. 

[aerobod - near CYYC]

There is a standalone barometric pressure sensor for the MBE ECUs that SBD sells. It is not the same as the Ford MAP sensor that is used by Caterham, that can be used outside the plenum or when there isn't a plenum, as a baro sensor. The MBE baro sensor has quite robust terminals and wiring pigtail supplied with it, I've had no issues with the one I fitted to my 9A4 ECU, it transformed the drivability of the car in the 1,000 to 2,000 metre altitude range I typically drive the car at: MBE Standalone Baro Sensor

[John Vine]

Excellent bit of diagnosis!  Easimap 1, Dodgy sensors 0.

Big capacity in-line 4cyl engines generate a lot of vibration, which makes them a particularly hostile environment for anything attached to them, such as sensors and connectors...

Indeed, and the problem seems to be more acute at the top of the engine.  As I mentioned earlier, COP and TPS wiring are often victims.  Now we can add MAP sensors!

JV

[vertew]

@JNC - I'm at ~350ft so default Baro value would be fine for me too.  There's always the 'next year' trip to the Alps, so I'm tempted to keep an operational MAP / Baro sensor (the trip has been 'next year' for some years now...).

@aerobod - thanks for the link to the SBD sensor + looping connector wires - much better ideas.  Hadn't quite clocked you're in Calgary CA, what an epic location to own a 7!

@John Vine - the engine is probably pivoting around its mounts lower down, so vibration at the top of engine could well be worse, amplified by resonance at certain rpms.  Easimap certainly nailed the problem - the cable should be provided by CC!

tks, Andrew.