John Vine Posted February 20, 2017 Share Posted February 20, 2017 Thanks, Piers.I think we've all been round this loop before, but I'm still puzzled whether or not: While cranking, the voltage is (a) sufficient to fire the plugs but (b) insufficient to fire the injectors Squirting in fuel (and then cranking) solves problem (b) and the engine fires Once the engine fires, voltage rises sufficiently to fire the injectorsIs this a likely scenario? If so, how do we go about demonstrating it?What contact cleaner are you using? Is it something like this (which claims to dry quickly and leave no residue)?Given that S&C fixed it by cleaning out the multi-plug, I suspect that's where your problem still resides. Are the various wires to and from the plug in good condition? No loose wires or terminals? Perhaps another trip to S&C would be a prudent move?JV Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 20, 2017 Author Area Representative Share Posted February 20, 2017 JohnI was using Halfords contact cleaner.I booked it into S & C this afternoon and they will have a go at it in early March.It has had the following done: ECU and Injectors checked by MBE Motorsport, new battrey, new starter motor, new crank sensor, new in line fuel filter, new HT coil, new Distributor cap, new rotor. new HT leads, and new MFU relay, although the original is back in the car.Piers Link to comment Share on other sites More sharing options...
John Vine Posted February 20, 2017 Share Posted February 20, 2017 Well, we're all on the edge of our seats once again, desperate to hear what S&C find!JV Link to comment Share on other sites More sharing options...
Bottrill Posted February 20, 2017 Share Posted February 20, 2017 Oh no!!Piers, as mentioned earlier, just double check there is no loose connectors in that multi-plug and that they are all seated correctly when fitted back together. Exactly the problem with mine and a previous owner. I believe he eventually found that one of the individual pins wasn't locating properly. Good luck!Lee Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 20, 2017 Author Area Representative Share Posted February 20, 2017 Hi LeeI thought the problem was found with the connector and it may still be the case that there is a bad connection in the plug. Tomorrow I will double check all the connections on both plugs. It does clip into place and now I can get it apart easily, I can spend some time looking at each wire.Piers Link to comment Share on other sites More sharing options...
revilla Posted February 21, 2017 Share Posted February 21, 2017 Have we had a photograph up yet of the offending multiplug? I'm struggling to work out which one it is from the description. Does this ECU support OBDII (or other diagnostics hooked up to a PC)? If so, does all the sensor data look sensible, particularly IAT? From the symptoms the scenario that John summarises above still sounds plausible but it's hard to see why that would be the case after all you've changed. Link to comment Share on other sites More sharing options...
Bottrill Posted February 22, 2017 Share Posted February 22, 2017 You can't miss it, it's the large grey multi plug under the TPS/throttle bodies. It's in a prime location to be hit with all sorts of road/weather debris from under/front of the car. Lee Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 22, 2017 Author Area Representative Share Posted February 22, 2017 I will get a photo tomorrow, as have been busy with new heating system being installed, until we hit a problem with "bats". Piers Link to comment Share on other sites More sharing options...
revilla Posted February 22, 2017 Share Posted February 22, 2017 Are we talking about the big rectangular connector between the main engine loom and the sub loom for the injectors, coil packs, IAT and MAP sensors? If so, I'm trying to think how it could cause these symptoms. It can't be the coil pack wiring or it wouldn't fire when you squirt fuel in. If it was the injector wiring, I struggle to see how it would consistently misbehave when cold and be fine when warmed up. It could be the IAT or MAP sensor connections, and the IAT would be a particular suspect - but the IAT sensor resistance decreases with increasing temperature and so increased resistance in the connections would tend to fool the engine into thinking that the intake air was colder and denser rather than hotter so would increase fuelling - I would be surprised if it caused cold starting lean issues, I would expect more hot rich running issues. Unless of course the connection is broken completely or so high resistance that the ECU realises that it is implausible and is falling back on default values which are unsuitable? I would really like to see some sensor data for when then engine is being awkward. Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 23, 2017 Author Area Representative Share Posted February 23, 2017 I have a photo that is PDF. How do you paste it in here ? Piers Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 23, 2017 Author Area Representative Share Posted February 23, 2017 /sites/default/files/images/users/7956/medium_IMG_0039.JPGHere is the photo Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 23, 2017 Author Area Representative Share Posted February 23, 2017 /sites/default/files/images/users/7956/IMG_0039.JPG Link to comment Share on other sites More sharing options...
elie boone Posted February 23, 2017 Share Posted February 23, 2017 If that connector is corroded internally then the only solution is to replace it. Link to comment Share on other sites More sharing options...
revilla Posted February 23, 2017 Share Posted February 23, 2017 Ah ... Thanks for the picture. Not the connector I thought you meant. That's the one that connects the engine loom into the main vehicle loom. I'll have a look at the wiring diagrams and a think about how that could be causing this. Link to comment Share on other sites More sharing options...
revilla Posted February 23, 2017 Share Posted February 23, 2017 OK if it's EU3, looking at that plug we have: Pin 1. Oil temperature sender. It's not that. Pin 2. Tachometer signal. It's not that. Pin 3. Earth for MFRU input plug Pin 6. Not sure why rover chose to earth one of the MFRU pins via the main loom, must be something to do with history which isn't reflected in the Caterham loom. Inside the MFRU that is only connected to the starter solenoid relay coil. So a problem here would only prevent the starter solenoid from engaging. It's not that. Pin 4. Immobiliser. It's a digital link, it's either going to work or not. And it starts when you spray in fuel. Immobiliser issues normally work the other way, the car starts and then dies (the ECU allows some time for th handshake with the immobiliser). I really doubt it's that. Pin 5. Supersport shift light. It's not that. Pin 6. Unused. Pin 7. Water temperature sender. It's not that. Pin 8. Oil pressure sender. It's not that. Pin 9. Fuel pump supply. But once started it runs and you say pressure was fine so it's not that. Pin 10. Unused. Pin 11. Alternator warning light. It's not that. Pin 12. Unused. Pin 13. Ignition switch. Doesn't match the symptoms at all, it's not that. Pin 14. Starter solenoid. It's not that.According to the EU2 wiring diagram it's pretty much a subset of the above.So I really can't see anything in that plug that could give the symptoms you described. I have a horrible feeling that this plug is a red herring. Like the crank sensor. You changed it and it appeared to fix the problem, but it turned out just to have stopped for a bit at the same time rather than have gone away.With those TBs is it easy to remove the fuel injector rail so that the injectors are just pointing upwards into the air? You could then see if they are spraying at all during craning (in a well vented place, preferably outdoors). If they are apparently spraying healthily, I'm totally stumped. If not, it's either the fuel pressure behind them or the electrical drive to them. I know you had the fuel pressure checked before but this fault does seem to be intermittent and it may just have been working OK when they checked it Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 23, 2017 Member Share Posted February 23, 2017 With those TBs is it easy to remove the fuel injector rail so that the injectors are just pointing upwards into the air? You could then see if they are spraying at all during craning (in a well vented place, preferably outdoors).Agree with the value of discovering this. Don't now if it's feasible.JonathanPS: "Cranking"... unless you're thinking of Heron heads. :-) Link to comment Share on other sites More sharing options...
JNC Posted February 23, 2017 Share Posted February 23, 2017 When when you spray fuel into the trumpets and then start the engine it fires and runs ok ! . To me it all points to a fuel delivery problem either volume or pressure ! , is it possible that once the engine is running the Pistons are pulling the fuel into the engine ? Link to comment Share on other sites More sharing options...
John Vine Posted February 23, 2017 Share Posted February 23, 2017 With those TBs is it easy to remove the fuel injector rail so that the injectors are just pointing upwards into the air? You could then see if they are spraying at all during craning (in a well vented place, preferably outdoors).Yes indeed. I had the same thought back in post #178:"...could he try removing one of the injectors to observe whether or not it actually squirts out fuel while cranking from cold? (I've never tried this -- is it even possible?) I imagine that would confirm two things: (1) whether or not the firing voltage during cranking is adequate, and (2) whether or not the fuel rail pressure is adequate."However, Paul D replied (in #179):"You could only pull out all four injectors, still attached to the fuel rail, but I wouldn't suggest switching on the fuel pump with them out of the engine as a) you'd be potentially spraying fuel everywhere and b) the pressure could easily blow the injector out of the rail coupling, even though they should be clipped in. The best thing would be to monitor the injector voltage and signal with an oscilloscope, however in the absence of one of those, monitor the supply side and signal connections with an analogue voltmeter. This is on the basis that, if the voltages look right then the injectors must be opening correctly and, assuming sufficient fuel pressure, fuel is being delivered to the engine."JV Link to comment Share on other sites More sharing options...
Dave J Posted February 23, 2017 Share Posted February 23, 2017 sorry if this has been covered but mine was a little reluctant to start until i balanced the roller barrels, now it's 2seconds and away from cold . Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 23, 2017 Author Area Representative Share Posted February 23, 2017 The Roller Barrels were balanced by Sevens and Classic, after they cleaned up the multi pin connector. Once it starts, it runs a bit lumpy to start with, but once warn, it ticks over fine. Piers Link to comment Share on other sites More sharing options...
JNC Posted February 23, 2017 Share Posted February 23, 2017 Have you done a compression check on all cylinders cold and hot ? Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 24, 2017 Author Area Representative Share Posted February 24, 2017 JNC. No, I have not done a compression check. I do not have the equipment to do that.Piers Link to comment Share on other sites More sharing options...
JNC Posted February 24, 2017 Share Posted February 24, 2017 It might be a good idea to get your engine compression checked ! , I think you've proved the electrics work by squirting fuel into the trumpets and it instantly firing ! , rather than looking at your engine as an engine look at it as a pump you are effectively priming the pump by manually entering the fuel via the trumpets thus wetting the bores sealing the compression and starting the combustion sequence. I would check the compression without adding fuel on all four cylinders then do it again when you've added the fuel , Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted February 24, 2017 Author Area Representative Share Posted February 24, 2017 JNC - I am sure that Sevens & Classics did a compression test back in September and it was one of the first things they did. It was all OK.Piers Link to comment Share on other sites More sharing options...
JNC Posted February 24, 2017 Share Posted February 24, 2017 Piers was the test done cold and then hot ? Link to comment Share on other sites More sharing options...
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