Bone Rat Posted October 22, 2020 Share Posted October 22, 2020 Hi to all,I was wondering if I could pick some brains about what is 'normal'. I've got a 2011 SIgma 150 Roadsport which I tend to look after myself. Cambelt done professionally but all servicing is in house. Up to now all has been fine. In September I was driving along the A48 at Bridgend when the car just stopped running when I stopped at one of the major roundabouts. Not good being stuck in the outside lane of a fast A road. Pushed to the side and waited for the RAC. The engine would turn over, fire for about a second but not run. There was a spark, the fuel pump primes, the TPS was fine. After a few hours by the side of the road - a big thank you to Dave in Porthcawl for checking up on me, I got home on a flat bed.Since then have checked over repeatedly, it turns over, fires but doesn't run for more than 1 -2 sec. Have browsed the site and changed TPS and lambda to no effect. Earths cleaned, battery fully charged, new plugs 2 years ago (3k miles), inertia wotsit checked & bypassed.Checking the immobiliser today, it's the Sterling type with the dongle and loop around the lock. The LED does not illuminate at rest at all, on turning the key to the power on position it gives 1 flash then nothing, turning off it gives 1 flash then nothing at all. There is no steady light when in the starting position or flashing LED when the key is removed.I was just wondering if the collective experience of the elders would be that it's not working correctly and stuffed. If so any suggestions about what to do or where to go, would this be a job for a local electrician to sort? I am game to remove one after many years of dealing with 1970s Fiat electrics! Many thanks Andy Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 22, 2020 Member Share Posted October 22, 2020 Private Message sent. Link to comment Share on other sites More sharing options...
ChrisC Posted October 22, 2020 Share Posted October 22, 2020 I can't help think the immobiliser is fine if it primes and runs for a few seconds. The fuel pump is controlled by the ECU, it wont run is the engine isn't running. So it makes me think the MBE isn't happy the engine is running.Have you connected it to EasyMap to see whats going on?I could be wrong about the immobiliser.I owned a 2011 150 Sigma, and I remember a fault which would cause the engine to die, which was caused by the speed sensor. The sensor would fail, kill a fuse and that would take the permanent supply out from the engine and tacho. Check your fuses, if you one blown and it keeps blowing disconnect your speed sensor and try again. Link to comment Share on other sites More sharing options...
richy Posted October 22, 2020 Share Posted October 22, 2020 Contact MBE in Cirencester if you think the ECU is faulty. They are very helpful. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 23, 2020 Share Posted October 23, 2020 sounds like the fuel pump feed / earth is being lost for normal running and its just running on pump prime pressure then stops Link to comment Share on other sites More sharing options...
Bone Rat Posted October 23, 2020 Author Share Posted October 23, 2020 Thank you everyone, they can be incredibly frustrating little cars at times. Winter is going to be interestingAndy Link to comment Share on other sites More sharing options...
John Vine Posted October 24, 2020 Share Posted October 24, 2020 Re #5:That's how it appears to me, too. The crank sensor (or its wiring) would be a prime suspect.JV Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 24, 2020 Share Posted October 24, 2020 Have you also looked at the TPS and the harness...? Link to comment Share on other sites More sharing options...
Bone Rat Posted October 25, 2020 Author Share Posted October 25, 2020 Hi, Yes, checked the various threads on the forum, unfortunately it seems a common set of symptoms. So far have a new lambda sensor as that had been in 10 years and was covered in soot. No joy. Then replaced the TPS and the small harness (it was on offer), again no joy.Yesterday, tried looking at the fuel pump and wiring, have cleaned the earths in the engine bay, the plug at the fuel pump looked fine with clean contacts, fuses are fine. It's odd in that the pump primes, it turns over readily enough, fires, runs for a few seconds, just as if it's on the priming pressure and dies.The mass of other connections seem buried above the gearbox and would tax a gynaecologist to get to, at least via the engine bay Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 25, 2020 Share Posted October 25, 2020 Easiest access to those is by taking the tunnel cover off. Link to comment Share on other sites More sharing options...
Garth Posted October 25, 2020 Share Posted October 25, 2020 The immobiliser on my Sigma did fail several years ago - had an auto electrician diagnose it - the red LED was not doing what it normally did which prompted me to investigate this. From memory however the car would not turn over - completely dead so probably not the immobiliser! The other problem I had once which behave in a similar way to what you describe is a damaged wire to the crank sensor?Good luck Link to comment Share on other sites More sharing options...
Garth Posted October 25, 2020 Share Posted October 25, 2020 The immobiliser on my Sigma did fail several years ago - had an auto electrician diagnose it - the red LED was not doing what it normally did which prompted me to investigate this. From memory however the car would not turn over - completely dead so probably not the immobiliser! The other problem I had once which behave in a similar way to what you describe is a damaged wire to the crank sensor?Good luck Link to comment Share on other sites More sharing options...
Eccles Posted October 25, 2020 Share Posted October 25, 2020 Could it be the fuel pump? It sounds like the immobiliser is working as the pump primes and the engine turns over which it won't if the immobiliser hasn't de-activated itself.I don't know but guess there is a pressure switch in the pump that causes it to run when needed to boost the pressure back up again and it sounds like that isn't happening.Just a thought..... Ivan Link to comment Share on other sites More sharing options...
John Vine Posted October 25, 2020 Share Posted October 25, 2020 I'm not familiar with the Sigma engine or ECU (I'm a K and D man), but does this ECU log the standard error codes? If so, would a code scanner not indicate the problem?Also, when trying to start and after the pump has been primed, what tells this ECU that the crank is turning and to turn the pump on? I've always understood that the crank sensor did this (it does in the K). If so, your symptoms certainly suggest a problem with the crank sensor signal. Either it's not being sent, or not being received.JV Link to comment Share on other sites More sharing options...
Bone Rat Posted October 25, 2020 Author Share Posted October 25, 2020 Many thanks for all the suggestions, I've ordered a new crank sensor this afternoon so will give that a try. Very frustrating as I'm in Wales and the lockdown seems to have been embraced. Hopefully it'll arrive early next week.Andy Link to comment Share on other sites More sharing options...
Bone Rat Posted October 25, 2020 Author Share Posted October 25, 2020 Hi John,As far as I'm aware the Sigma can't be read by the usual fault scanner as it's a locked MBE unit. Tried when I first bought it years ago. I've had to use a generic one on my previous TT as this was plagued by emission code errors. I've got the Easimap software as the 150 needs throttle body balancing and TPS setting on a regular basis. This gives a live reading of engine parameters but no codes appear stored (I think). Can't say I'm that familiar with the detailed use of it thoughAndy Link to comment Share on other sites More sharing options...
John Vine Posted October 25, 2020 Share Posted October 25, 2020 Re #16:Thanks.JV Link to comment Share on other sites More sharing options...
ChrisC Posted October 25, 2020 Share Posted October 25, 2020 Hi Andy If it runs for a few seconds, there should be some data coming from the MBE which shows the reason. If you connect the EasyMap software, add all the data panels so everything possible is being logged, try and start it, then save the data. The data files could then be shared. I still have some data files from my 150 which I could compare your car with, happy to look at the data to see if there is anything obvious. Chris. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted October 25, 2020 Share Posted October 25, 2020 With Easimap, a few panels that could be added if not already on the logging page, that could give a clue to the crank sensor state would be:- Cam Sensor Setup - Engine Synch Status- Cam Sensor Setup - Sync Window- Fault Conditions - Fault List- Development - Crank Count- Development - Bad Missing Tooth Count Link to comment Share on other sites More sharing options...
Bone Rat Posted November 18, 2020 Author Share Posted November 18, 2020 Just to update things, new lambda, new TPS and harness, new crankcase sensor and plugs. Fuel pump is OK. Still no joy, now waiting for Eric from Millwood to collect it - I give up, a perfect end to 2020.Will update on the eventual solution Andy Link to comment Share on other sites More sharing options...
Eccles Posted November 19, 2020 Share Posted November 19, 2020 That's a shame, was sure one of those would be the culprit. How long will you have to wait for the car to be collected with the restrictions etc.?Ivan Link to comment Share on other sites More sharing options...
Area Representative Iain McCallum Posted November 19, 2020 Area Representative Share Posted November 19, 2020 Way back in 2011 when I built my 150 Sigma I had the same issue on initial startup. Caterham fixed it at the PBC by balancing the throttle bodies and then setting the TPS to 1.04. They assured me that was all they did! I now do this every year!!Sorry you are having that problem. Iain Link to comment Share on other sites More sharing options...
Bone Rat Posted November 19, 2020 Author Share Posted November 19, 2020 Hi Hopefully be collected next week, been sitting there for ages since September Be fascinated to know what it is Link to comment Share on other sites More sharing options...
John Vine Posted November 20, 2020 Share Posted November 20, 2020 Well, if anyone can sort it, Eric can. Looking forward to hearing his diagnosis.JV Link to comment Share on other sites More sharing options...
Bone Rat Posted December 4, 2020 Author Share Posted December 4, 2020 Hi all,I thought I'd update everyone with progress, I hate threads being left up in the air and not resolved, hopefully this will help someone else.So far I'd replaced the TPS, the little harness to it, the lambda sensor and the crankcase sensor. No joy. The only problem I could see was the malfunctioning immobiliser LED. So off it went to Eric in Millwood.have spoken to Eric and it was 2 things.The main problem was caused by a failure of the barometric sensor, this is apparently very rare and was detected a little by luck as it was disconnected. The 150 has it mounted on the air filter back plate, possibly it's a bit exposed. He did say he hadn't come across this before.In addition to this the fuse to the immobiliser had also blown which meant it would not run once it did fire. Unfortunately this is also hidden and is not part of the usual fusebox but part of the loom.Feel a little more reassured that this was not a simple problem that I should have been able to fix.Collecting it in a few weeks - will be getting aeroscreen fitted, brass monkey for co-driver for return trip.Thanks to everyone for their suggestions Andy Link to comment Share on other sites More sharing options...
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