LeatherTan Posted October 29, 2025 Report Share Posted October 29, 2025 Morning all! I wanted to ask if my situation gives anyone any bright ideas🤓 So, Lupo has been faultless for a quite some time (even had a 1000km+ north-west euro trip this summer, and didn’t skip a beat). Now in the last couple months, I’ve had 2 of the same problem occasions. It goes like this: Car has sat for a few weeks…, 2, or so. Go to start and it turns over but doesn’t start, with no ‘other’ signs of flat battery. Multimeter shows 12.69. The brake pedal has a very hard/solid feeling to it (not the usual softer-feeling easy depression). If I turn the ignition on (dash lights/coil light extinguishes etc.) and *then put my foot on the brake (hard feeling) the green ‘foot on brake’ light doesn’t go out, even using both feet on the pedal with lots of force. If put my foot on the brake before turning on the ignition, not with crazy pressure either, then the green ‘foot on brake’ light doesn’t come on and it’ll turn over. The first time it happened it eventually started after many attempts…, but the time it did start the brake felt normal as soon as the engine was turning over. . Yesterday morning I had the same rigmarole but to no avail, even giving it a good 10-15 tries. The brake pedal always staying stiff-feeling, and behaving strangely (with the green light not going off when pressing, sometimes real firm). A few things: I tried with the shifter in neutral as well as stop. Tried rolling the car back/forwards a bit. Looked for any obvious loose connectors around the accumulator/slave cylinder areas. My drivers-side door microswitch is kaput so the Lupo doesn’t recognise that bit of the circuit. There seems to be something odd with that stiff brake pedal feeling (which has occurred before and not given me any starting problems) and it’s usually after it’s sat for a while…., this time for 9/10 days. I have no fault reader, either. Maybe my brake pedal switch has had it (the 2-in-1 switch)? My brake lights do work….🤔 It may just require a lift to my garage on the back of a breakdown truck? Any words of wisdom greatly appreciated and have a top Tuesday, everyone🫡 Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 29, 2025 Report Share Posted October 29, 2025 No vacuum stored in the brake servo (no brake force assist). Check vacuum hoses (they crack at the joins), vacuum pump and lastly the servo (unlikely) 1 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted October 30, 2025 Author Report Share Posted October 30, 2025 Nice! I’ll fire up my ElsaWin guide and find out as much as I can about the whole vacuum/brake arrangement…., at least to then pass on to the garage🤓 Thanks for the steer, Mk2🍻 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted December 26, 2025 Author Report Share Posted December 26, 2025 Morning, club, and seasons greetings! I trust a merry time is being had by all🍾🎁.... Here I still have some 'starting' issues, however😬 After fitting a new camshaft speed sensor (after a fault reader scan), a new break pedal switch, and a new ignition switch, the 3L still has some hesitation on startup, with some odd behaviour, too. In STOP she usually takes more cranks (if starting at all) and most goes will just 'give up' cranking after several spins..., but very occasionally will keep trying to turn over. In N she will start where she has failed in STOP (interestingly not needing the brake pedal pushed in N), as if finding it easier, but what's 'different' by having the selector in STOP or N? Also, if deciding to start(🙄), there's a high pitched rattle/spinning/wheezing sound (for only a second), which isn't every time, and the mechanics told me is a just a common element of starter motors being a bit noisy and not that the starter motor is packing up(?). Is this all a bit indistinct to advise on? Happy Boxing day, all! Quote Link to comment Share on other sites More sharing options...
Benutzername Posted December 30, 2025 Report Share Posted December 30, 2025 The starting speed is quite important for this type of diesel engines. Starting problems, such as those you describe, often occur when the cold season begins. The battery becomes slightly weaker and a new battery often temporarily solves the starting problem. However, the problem actually lies with the starter motor. It works perfectly mechanically, but the starting speed is not sufficient. You can check this relatively easily by connecting a second fully charged battery or, better still, another vehicle. If the slightly higher voltage level solves the problem, experience shows that it is the starter motor. 1 1 Quote Link to comment Share on other sites More sharing options...
lupo 1.7sdi Posted January 3 Report Share Posted January 3 A voltmeter would be useful to monitor the battery voltage (I have a USB charger with a voltmeter that I keep plugged into the cigarette lighter socket all the time). The behavior of an ok battery would be as follows: immediately after turning off the engine (after driving 10-15 km) the voltage should be somewhere between 12.6-12.8V. After turning off the engine and locking the car, the voltage drops to 12.5V in 10-15 minutes or more depending on the condition of the battery, and will drop by 0.1 V in 6-7 days (for a new battery) of course if it is not connected to anything during this time. If after a night the voltage drops from 12.5 to 12.1 V or less, then the battery is tired or not sufficiently charged. If you make short trips and have many starts in a day, it is possible that it is simply insufficiently charged. A full charge on a rectifier might help in the latter situation. If the battery is over 4-5 years old I think it should be replaced (after the OE battery that lasted 12 years, the next one lasted 6 years, and the current one is almost 5 years old and shows signs of fatigue if the car is not used for 2-3 days in the cold season) 1 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted January 3 Author Report Share Posted January 3 Hi, guys... Happy 2026!! Thanks, both, for your replies. I should be able to monitor some of that and observe what's going on a bit more acurately. Since getting home the other day we went out but konked-out (due to running empty.., the fuel level warning lamp, helpfully lights up when low, only some of the time😅) and after getting a top-up to drive home she sat for a week then... wouldn't start at all. No 'click', couldn't cancel the brakelight switch as the brake pedal was super stiff..., also couldn't move the shifter out of 'STOP' to attempt a start in 'N'. If there was a vaccum issue (stiff brake pedal?) then wouldn't my brakes feel super 'off' or just not really work (when she does get going, that is)? Will keep on keeping on and update as and when! Take care! Quote Link to comment Share on other sites More sharing options...
tigcraft Posted January 4 Report Share Posted January 4 I don’t know enough about the 3L but what I will say is buy yourself a ‘power probe’ it’s a tool that is so important to bypass systems. Basically it’s a probe that not just tells you there’s a circuit but it lights green for earth, red for positive power and then the fun bit, you can send a current of either negative or positive through it to crank your starter solanoid direct without pressing the brake!! It WILL turn your engine over! 1 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted January 9 Author Report Share Posted January 9 Cheers, tigcraft! I can look into that as well. May be a helpful addition. Quote Link to comment Share on other sites More sharing options...
lupo 1.7sdi Posted January 10 Report Share Posted January 10 A few observations so you can compare the behavior of a new battery to a tired one: yesterday after two days of not starting and cold at night, I had a hard time starting. Basically, the battery voltage was 12.1V and it started on the second try. On the first try, the voltage dropped to 8V and the starter almost stopped. So I went straight to the battery store. The battery still had about 67% capacity so I bought a new one. When I installed the new battery, it had 12.6V and I drove 12km home. After about 30 minutes of parking, it had 13.1V. This morning, after a night with -10 degrees Celsius, it had 12.8V and it started instantly. With the old battery, when I turned on the ignition, the voltage dropped to 10.5V (due to the glow plugs) and after the glow plug light went out, it didn't rise above 12V. Now it drops to about 11.5V (this depends on the outside temperature of course) and then rises back up, I don't remember exactly, it seems to be around 12.5V. 1 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted January 10 Author Report Share Posted January 10 Thanks very much for the update, with your experience. I'm just going to get out in the boot (where the battery lives) with my multi meter, now, actually. Let's see😬 Quote Link to comment Share on other sites More sharing options...
LeatherTan Posted January 10 Author Report Share Posted January 10 Ok! So on resting (having sat for several days) the reading was 12.4v. I thought 'not ideal but let's give it a go'. I was working alone so had no way to monitor the readings whilst cranking, anyway.... Turned over and once running was settled at 14.28v. That, from what i've read, seems fine as a basic measure of the battery state, and charging. It was the same after a 25 minute run. More to the point: Brake pedal still pretty stiff, but had a tiny amount to depress, so the green dashboard foot-on-brake-pedal light did extinguish. Thought if I only had one shot I'd stick it in 'N' and not risk a fail with the slightly more 'iffy' 'STOP' position and, hey presto, after a few mildly sluggish cranks (which I'd expect anyway from the time since last being driven) she fired up. The drive was really good with no other dodgy signs. I used both standard and ECO driving modes/maps and behaviour was pretty normal (although I switched off ECO mode coming to a stop as I didn't want to risk a non-start if the 'stop-start' didn't behave). So we'll see how she goes from now, but wish us luck! And I really appreciate members advice and comments. 1 Quote Link to comment Share on other sites More sharing options...
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