scotty2 Posted September 5, 2022 Report Share Posted September 5, 2022 Our 1.416v Lupo has cut out a couple of times now in the last two weeks. Driving along, it's as if someone has switched the ignition off. Car engine cuts out slows to a halt. Switch off and it restarts. Then drives as if nothing is wrong. Any likely common fault that would behave like this? I'm thinking Crank Position Sensor? I have an OBD reader, but it won't link to the Lupo. Any tips? Quote Link to comment Share on other sites More sharing options...
mk2 Posted September 5, 2022 Report Share Posted September 5, 2022 Yeah crank sensor is a common one for those symptoms. But also common in Lupos is ig switch and main bus power relay (behind fuses). VCDS software is your friend here... 👍🏻😀 Quote Link to comment Share on other sites More sharing options...
Skezza Posted September 5, 2022 Report Share Posted September 5, 2022 Do 1.4 16V's have relay 109? Quote Link to comment Share on other sites More sharing options...
ObjectiveAway Posted September 6, 2022 Report Share Posted September 6, 2022 16 hours ago, scotty2 said: I have an OBD reader, but it won't link to the Lupo. Any tips? Try to make the OBD to wait on “connecting” phase, only then turn on the ignition, works for me. Quote Link to comment Share on other sites More sharing options...
mk2 Posted September 6, 2022 Report Share Posted September 6, 2022 You need to set the comms interface to use the k-line (older, slower protocol) on your OBD kit. 👍🏻 1 Quote Link to comment Share on other sites More sharing options...
scotty2 Posted September 11, 2022 Author Report Share Posted September 11, 2022 New sensor has arrived. I put the car up on the ramp but can't find it! Where is it located? Is it a starter motor out job? Quote Link to comment Share on other sites More sharing options...
ObjectiveAway Posted September 12, 2022 Report Share Posted September 12, 2022 17 hours ago, scotty2 said: New sensor has arrived. I put the car up on the ramp but can't find it! Where is it located? Is it a starter motor out job? Yes, starter out and 1 screw is holding sensor in place. VW use the silly 4mm hex bolt as OEM, and usually it just tears apart instead of coming loose. If you have 5mm bolt as replacement use it. You can easy check if your sensor is really malfunctioning. Lupo crank sensor has 3 wires, when it is connected and reading the middle wire should show +5V or 0V. If the sensor shows +5V (when reads magnetic surface) or 0V (when reads nothing) it is working, to make sure installed sensor is working turn your crankshaft, easiest way to turn it a bit is puting your car in gear and pushing it tinybit. You can use this method to check both your old and your new sensor, more over you can even check sensor which is not installed, just put bottom of sensor near any magnetic surface. Quote Link to comment Share on other sites More sharing options...
scotty2 Posted September 12, 2022 Author Report Share Posted September 12, 2022 Cheers! Quote Link to comment Share on other sites More sharing options...
scotty2 Posted October 19, 2022 Author Report Share Posted October 19, 2022 Crank sensor now changed and selector rod oil seal too. My son is now convinced the car is driving much more responsively and "much better". Is this likely? I thought it would be a case of it works or doesn't. Anyway, let's see if that was the issue. Quote Link to comment Share on other sites More sharing options...
lupogtiboy Posted October 19, 2022 Report Share Posted October 19, 2022 I recently changed the crank sensor on my GTI, was a pain in the ass to do. Mine was fine until it warmed up, then it would jump, like it had a massive misfire, then drive with about half the power it should have. When it first did it, I turned it off then on again and it was fine, but after a week or so, it brought the EPC light on. I've now fitted a new sensor and all is well again! Quote Link to comment Share on other sites More sharing options...
scotty2 Posted October 25, 2022 Author Report Share Posted October 25, 2022 Well the car is still cutting out, and getting more frequent now despite the new crank sensor. Seems to happen when he is going down the gears when slowing down for corners or junctions if that makes any sense. Taking it to local VW guy who is going to see if there are any codes. Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 25, 2022 Report Share Posted October 25, 2022 Bummer. Ok, so next step is main power relay, then ignition switch. Could be a loom issue or high voltage ign module connection, but unlikely. Diagnostics might not show those faults, as they can be interpreted as user action. Like, why would you turn off ignition while driving... but hey. Let us know what you find... Quote Link to comment Share on other sites More sharing options...
scotty2 Posted October 25, 2022 Author Report Share Posted October 25, 2022 Cheers. Will let them know. What part number is the relay, or is it this? https://www.ebay.co.uk/itm/222094199561?fits=Car+Make%3AVW|Model%3ALupo&epid=670991295&hash=item33b5d88b09:g:kzsAAOSwqWNZAJ4R&amdata=enc%3AAQAHAAAAsIFm%2FmZB%2BbUqibtgGWCw9r1J3trjpcnmX4RXryuPT8oLth%2Ba8Vu%2FV8eQgs3PmGXuxEmEunTqfRIdQdARLHbdl5WIbCJ1Xy61ZYunQ5QjVg%2ByzhOk7zoX3GpW6GLdJfrPZP89yhe1IXeTX3XbBEhcUcQ8oEE4M9RPVTW1mOjfrWxc6erybQpoyrVGz0Oigi%2FYJJq%2FtJX4nPgsk4G43x1tM7WkR1%2B%2F9%2BOHlwqmPrKfNMUH|tkp%3ABk9SR_afl-aBYQ Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 25, 2022 Report Share Posted October 25, 2022 I can't remember the relay model number (109 maybe?), but if they know what they're doing, it's fairly easy to simply unplug the relay and test it. While there, the others can also be quickly checked. Takes seconds to pull them out one by one and test with a meter, or just by swapping them around. Just like a fuse. Swapping over the ignition barrel switch is a pain. There's a "how-to" on here somewhere with lots of pics. 👍🏻 Quote Link to comment Share on other sites More sharing options...
scotty2 Posted October 26, 2022 Author Report Share Posted October 26, 2022 Only fault code was air flow, which was possibly the effect of cutting out rather than the cause. I'll have to try and get at the relays at the weekend. Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 26, 2022 Report Share Posted October 26, 2022 Ah, might be something else... Does it cut out while driving or while idling? If idling, it's probably not the above things- Throttle body or throttle position sensor (or wiring), or even a manifold leak, but then you'd get a different code, like O2 sensor, injector or mixture. Quote Link to comment Share on other sites More sharing options...
scotty2 Posted October 27, 2022 Author Report Share Posted October 27, 2022 He tells me it happens when slowing down for a junction or tight corner when changing down gear. Seems to be when the clutch is in and coasting while getting into the next gear. Quote Link to comment Share on other sites More sharing options...
mk2 Posted October 27, 2022 Report Share Posted October 27, 2022 Hmmm. Sounds like a wiring fault, like a loose plug or similar, probably related to ignition system. Any change in fuel consumption? If no, then more likely an ignition issue. But TBH, I have no idea. Intermittent problems are tricky to find. Trouble is, by the description there are so many things that can cause the exact same symptoms. But slowing down and cornering points to something disconnecting, when given a pull in a particular direction. But switches can do that. Relays can do that. Plugs and sockets can do that. A broken loom wire can do that. Do the lights or dash instruments flicker at all when it cuts out? Quote Link to comment Share on other sites More sharing options...
scotty2 Posted January 15, 2023 Author Report Share Posted January 15, 2023 No more engine cut outs since my last post. Just MOTd but had issues with emissions. I've posted on the "New Member" thread. "Running rich. The temp gauge reads OK. Is it possible that the sensor is still faulty and is telling the car it is "Cold" and over fuelling when it is actually warm? Sounds smooth when running with no EML. Not smokey either. Any top tips for poor emissions? " Quote Link to comment Share on other sites More sharing options...
mk2 Posted January 15, 2023 Report Share Posted January 15, 2023 Yeah could be temp sensor. Even replacements fail... I had a mk4, and over 10 years went through 4 of the damn things. Can't believe they didn't end up giving them away, as every Vdub model had issues. Even the flagship Phaeton. But could be throttle body gunged up. Or O2 sensor if it has one, but they don't usually fail. Clean air filter? Quote Link to comment Share on other sites More sharing options...
scotty2 Posted January 23, 2023 Author Report Share Posted January 23, 2023 Fitted a new temp sensor - well eventually! New one had too small an "O" ring so leaked. I swapped the rings over and fitted it. Now the temperature gauge will not go above the bottom of the 70 C bar. Took it for a good run and let it idle. Fan cut in as it should, but temp gauge didn't go above 70. It did move off the stop, but just. Picking another new sensor today. Air filter is clean. Quote Link to comment Share on other sites More sharing options...
lupogtiboy Posted January 23, 2023 Report Share Posted January 23, 2023 Could also be the MAP sensor on the end of the inlet manifold, quite prone to becoming dirty over the years. Would also explain the 'air flow' fault? Quote Link to comment Share on other sites More sharing options...
mk2 Posted January 23, 2023 Report Share Posted January 23, 2023 (edited) 8 hours ago, scotty2 said: Fitted a new temp sensor - well eventually! New one had too small an "O" ring so leaked. I swapped the rings over and fitted it. Now the temperature gauge will not go above the bottom of the 70 C bar. Took it for a good run and let it idle. Fan cut in as it should, but temp gauge didn't go above 70. It did move off the stop, but just. Picking another new sensor today. Air filter is clean. Gotta love them vdub group temp sensors from that era. The reason they all fail is because the resin they used to encapsulate the tiny bead thermistor (two of them actually), in that brass housing, expands at a different rate to the brass and the thermistor. So when they encapsulate them on a cold day in the factory, the stresses that build up when at running temp (90c) are so high, they actually crack the thermistors, or tear the welds away from the plug contacts. Really dumb. When cooled down again, they reconnect. Lovely. Similar problems to ABS sensors actually. Epoxy resin compared to polyester resin. Sigh. SMH. Yeah keep us updated on your ongoing quest. We're all learning from your observations. 👍🏻😀 Edit: yep, @lupogtiboy is right. Worth checking the gunge buildup and washing it with some brake and clutch cleaner... Edited January 23, 2023 by mk2 Quote Link to comment Share on other sites More sharing options...
scotty2 Posted January 25, 2023 Author Report Share Posted January 25, 2023 Fitted the 2nd new sensor today and it reads correctly. Will have to go and see if it has made a difference on the emissions. If not, then MAP sensor next suspect. Quote Link to comment Share on other sites More sharing options...
scotty2 Posted February 1, 2023 Author Report Share Posted February 1, 2023 (edited) Is there a Lupo workshop manual (Book rather than PDF) available? Just had a search but could only see downloads. I like a book. Having the new temp sensor checked today. ETA: New sensor reads OK. Will see about getting emissions re checked and then fit new cat if still iffy. Edited February 2, 2023 by scotty2 Quote Link to comment Share on other sites More sharing options...
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