Hello all, Relatively long time lurker first time poster. My megane rs 225 developed issues with starting recently. It had been parked up for a few months awaiting some work, however, it was periodically started and ran to keep it ticking over. All was well until the day before it went in, typically. The electrics went a little mad after washing it, so after researching things I stripped, cleaned and reassembled the fuse box. Still no joy, dash was saying injector fault so these were changed for new ones, battery didn't seem too healthy so a fresh one was installed. After this, still no joy. Borrowed a code reader and found the error df361 and df362, ignition coil circuit open or short circuit to earth. I was advised to change the TDC crank sensor, which I just did and still, no joy. I was hoping some of you might be able to advise the next logical and possible steps, as unfortunately, I'm not sure where else to turn. All advice and suggestions welcome. Whilst I wait, I'll try and do the drop links, anti rotation links, inner and outer tie rods and aux belt and tensioner. Fun bank Holiday for me... Many thanks in advance!
All the codes were cleared after fitting the new battery, the df361 and df362 codes were the only ones outstanding following that.
Fitted new a new coil pack, cleared the codes and the car managed to start briefly once or twice and then cut out. A rescan showed the same fault, df361 and df362. Cleared these again, and the car isn't starting, showing the fault "check injection" on the dash and the same codes again on the scanner. For what it's worth, there is a gentle tone coming from the engine bay following a failed start, and when the fuel pump is working you can smell petrol when it doesn't work. Could it be the fuel pumps gone? No obvious leaks were seen underneath and the smell seemed stronger from the cabin. Any help or suggestions are much appreciated.
Try a new crank sensor, sold my 225 years ago and within a couple of days it wouldn't start, swapped the sensor it fired straight up. A generic code reader can give some real false diagnostic's
If you push and hold the start button without pressing the clutch peddle, can you here the fuel pump run ??? it will only rum for a second or so
Indeed, I tried starting it following the method you describe to prime the fuel pump, you can hear it activating. The mild hum so to speak. The times it did start, since the new coils were fitted, were very short lived. Maybe 5-10 seconds at best. Prior to the coils I couldn't get any ignition.
Pull off the fuel pipe from the fuel rail and do the same with the start button. Put the end of the pipe into a small container to see if any and how much fuel comes out.
Thanks for the suggestion regarding the fuel line. I tried and gave up before I broke something, I recall it being stubborn when doing the injectors but today it felt like it was going to snap between my overall mood and lack of patience. However, I believe its ok as the fuel rail and line were plenty full when doing the injectors. Furthermore, it started today and ran briefly for approximately 10 seconds, then shut off, same issues again. "Check injection" etc etc. I'm close to calling the AA and schlepping it over to Fish Brothers to get comprehensively rinsed. However, if anyone has access to Clip in Wiltshire and can help before so, let me know (beyond optimistic but hey ho) and I'll surely treat you to a crate or two!
There maybe fuel in the fuel rail, but it needs to be at 3.5bar when the engine is running. if there is less then it will run a weak mixture and the lamba sensor will pick it up, suggesting that there is a fuelling issue "check injection"
I'm going with your suggestion as it seems logical, before I throw in the towel and have it dragged to my local dealership. I just went to remove the old fuel pump, however, I noticed it had only one line connected, the green one, and the red return line was nowhere to be seen. A little odd, but not unheard of? The lock nut ring was its usual difficult self, I'm now ordering some 6 inch pipe to attempt to fashion a tool. Any other tips on that particular joy are welcome, punches and attemped leverage with a set of locking jaw pliers and screw driver were, unsuccessful.
They don't have a return line, there maybe a vapour line I have one of these https://www.ebay.co.uk/itm/29526967...OhB76hbivpQuZCqjMLxu4ObkU=|tkp:Bk9SR5Kwh_OIZA There's plenty of different types available https://www.ebay.co.uk/sch/i.html?_....l1311&_nkw=fuel+sender+removal+tool&_sacat=0
Thanks for the heads up on the tool, ordered. Fingers crossed. Yeah the vapour line is interesting, some videos its clearly present, others not. As to why, I'll leave that for another day to worry about haha.
Fitted the new fuel pump, that tool was a little fiddly but we got there eventually. Car started on the button after priming the pump, fuel gauge worked as it should. Managed to get it to run for approximately 2 minutes, maintaining 1200 - 1500 rpm with the throttle, idle rpm dropped to 900 - 1000 and felt close to stalling. Eventually cut out, service light comes on. Won't start. I'm going to do the fuel filter next as I bought one alongside the pump, thats my last roll of the dice. Is it anywhere unique on the RS models? A quick check underneath didn't match the auto doc videos (granted, it wasn't the most thorough of searches).
225 and the R26's don't have a fuel filter, (the only one is the one under the fuel pump), the Mk3's do and it's on the drivers side towards the rear wheel underneath the car. The next thing i would try is a current check on the wiring, you will need a clamp meter and put it around the pump supply wire, this will tell you of the pump is cutting out or not, it's hard to here the pump when the engine is running.
How strange, no fuel filter. That'd be why I was struggling to find it underneath haha. Would the clamp meter go over all of the associated wires? Or do I need to clamp a single one going to the connector. I suppose my next question would be, even if I do find issue, what's the next step? Electrical systems aren't my forte (to be fair, I have no forte, but that especially confuses me). I may try to grab one today from screwfix, however, I have a feeling an AA tow to Fish Brothers is in my future...
The clamp meter will go over just one wire that is power feed to the pump,this is to see if the power to the pump stops before the engine stops, if so it's more than likely an ECU fault, or a trigger to the ECU
So, got the car recovered to Fish Brothers in Swindon for diagnostic, it was traced to the UPC unit and ECU. They don't stock those parts anymore, but at least we're closer. Cars now recovered and home. Weirdly, the car started at the garage and here upon delivery, however, I don't quite trust it to drive haha. I've read about swapping the UPC from breakers etc, however, I was wondering if anyone has any knowledge of firms that can test and repair the modules? We're getting closer haha, thanks for all the advice so far.
