CageyH

Once back at home, the car refused to start again. As it is two hours away, there is not much Incan do to help my colleague.

Head unit Part number is 3V0035820

Where can I download the MOI3_EU_SKMQB_R23802P file?

Good news - my colleague made the two hour drive home without breaking down. The problem with the over 90km/h fault is that when this happens, there are no fault codes logged. I think it is linked to the loose battery terminal, and the EVU resets itself, due to a dodgy power supply. I have asked my colleague to try the car now that the starting issue is fixed. She is going to try it soon, and let me know.

100% starting record since I tightened the battery terminal. The “coughing” did not happen today either. My colleague is driving home tomorrow, so hopefully she will make it without breaking down on route. She also tells me that if she goes above 90km/h, she gets the dashboard lighting up like a Christmas tree, and a beeping, and is forced to restart the car. I asked her if this started the same time that the garage replaced her battery, but she does not remember. I am starting to think that the car has a few more serious electrical issues, which I am not sure I want to tackle.

The car started again this morning. My colleague did not drive it in, as she said “it coughed” and she did not want to get stranded. Now I need to work out what “it coughed” means.

The car started again this morning. That is a 100% record since tightening up the battery connection. Is it too early to declare it is fixed?

Battery voltage was 12.5V after she started the car, and had turned the engine off. I am not 100% sure it needs a new battery yet. We will see what happens between now and Monday.

My colleague has just let me know that the car started ok, but was a bit lazy to start. Progress… I will keep an eye on it over the next few days.

Thanks. I was Googling after asking the question. You beat me to it. I remember seeing above 200 rpm when I looked yesterday, and there was not a significant difference with the booster fitted. The big difference was that the booster was fitted to the lead, before I tightened up the loose terminal. I am hoping that I get some positive feedback on Monday that the car starts fine, as after tightening the terminal, it started on the button.

Any idea of what the minimum cranking rpm is? It is something I can check with my code reader, using the live data stream.

No start/stop as far as I am aware. I don’t think the battery was coded. I will check. I was going to fit an AGM for the increased CCA capacity. For me, the higher the CCA, the better.

Agreed. This is why I did not want to replace the battery yet. The garage where my colleague had the work done had visited the car recently because it would not start, after they had serviced it. They found no problem with it. The problem is that the garage is about two hours away from where she works. My other thoughts are that one of the relays may be a bit tired, and the extra current available from the booster pack is (more than) enough to operate it. I will see how things progress over the following week, but I am looking at an AGM battery with a higher CCA than what my colleague has fitted. The battery fitted is one typical of a “country” garage here in France. It is a brand I have never heard of, and I have my doubts over it’s capacity. My colleague told me that her problems started when the garage changed the battery. It could be that the terminal has been loose since then. I hope my colleague will keep me informed over the weekend.

I guess a cold cranking test can be done by just measuring the battery voltage across the terminals while starting the engine? What is the target voltage? I would have spent longer troubleshooting, but the weather was not very good.

There was no noticeable difference in cranking speed with the booster pack connected. When I disconnected the booster pack, I did notice that the +ve battery terminal was a little “wobbly”, so I have fixed that minor problem.

When the car would not start initially, it was 12.36V at the battery terminals. After starting it with the booster pack, and a 15 minute drive, it went up to 12.88V. My colleague had tried to start the car several times during a two week period, hence the battery level being a bit low. This is why I have asked her to try and start the car, and measure the battery voltage if it does not start, as I went to see if the battery is faulty.

I have left my colleague a multimeter to measure the battery voltage, and the booster pack. I measured the voltage without the engine cranking and it was at 12.36. It dropped just below 12V on cranking. I should have more info on Monday. The battery was replaced 2 years ago by her local garage. If someone can point me in the direction of gaining access to the relay panel, that would be great. The car is a 2007 1.4TDi 80BHP, if that helps.

Dragging this thread back up. My colleague who has a problem with her 1.6TDi Roomster also has a 1.4TDi that does not start for her. I went round to have a look. She tried to start it. The motor turns over, but will not start on just battery power. No codes were found in the ECU. I popped my Noco GB50 booster pack on the battery terminals, and it immediately fired into life. I removed the booster pack, the car starts fine. My thoughts are to replace the Fuel pump/ECU relay. Do you think that is a good idea? If so, where do I find it on an early Roomster?

Ou of interest, would an injector failure show up on a diagnostics scan? I have a colleague at work who owns a Roomster 1.6Tdi, and the engine cut out, and will no longer start. The garage she took it to says it is a mechanical issue, and want to change all 4 injectors, but surely there should be some kind of fault code? I was wondering if it could be the in-tank fuel pump?

The Cinturato P7 have lasted 20k miles. I have a few more thousand left in them, but I will be changing them before winter comes.

Another question. If I went for Bridgestone Turanza 6 due to the lower rolling resistance, realistically what percentage fuel economy would they deliver compared to a higher rolling resistance tyre? I have found an online calculator that suggests that changing just two tyres will save me £10 a year. It hardly seems worth it to me. The EU tyre calculator suggest there is a potential 1% saving by going from a Group C to Group B tyre. Do real world experiences match the predictions? I am only changing 2 tyres this time around, I think I am just going to go for one of the Premium tyres in the daft size fitted to my car.

That is a very valid point, well presented. Thanks.

Thanks. The Premium Contact 6, rather than the 7? Any reason I have missed to not buy the 7?

Thanks for the response. Pirelli Cinturato P7 currently fitted. I have had a look today, and there really not many “Eco” tyres in this size. Lowest rolling resistance seems to be the Bridgestone Turanzo 6, but best life seems to be the Michelin Pilot Sport 5. To be honest, any of the “premium” brands will probably be absolutely fine. I don’t use this car for sporty driving. It is a family barge and commuting use only.

In my IV, I have averaged 2.8l/100km over the last 1200km. And before that, 2.3l/100km for 4650 km.