Pwyll Posted January 13, 2011 Share Posted January 13, 2011 Right! 3.9 EFi serp V8, N reg, non spider Discovery Started to play up a week or so. Would start when it felt like it. As the symptoms were exactly the same last time the ignition amplifier went down a new one was purchased courtesy of DiscoAl's Aladins cave. Fitted new amplifier, jump started due to flat battery, fired but popped a bit when revved. Tweeked distributor to get timing right, ran fine. Turned ignition off, tighten clamp on distributor, bloody thing refuses to fire. Things that I do know - There is a spark (took plug lead off, inserted screwdriver, turned engine over with screwdriver held close to shock turret) There is fuel (checked at schraeder valve on injector rail) So, given that it has all that it needs to fire, and in the correct order too because it ran before, what could be the fault with it? I need this hoing by Monday, as I start a new job and need it to get there. Thanks in advance, Paul Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 13, 2011 Share Posted January 13, 2011 Does it smell of fuel when cranking & failing to fire? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 13, 2011 Share Posted January 13, 2011 Pull all the plugs out and put them in the oven for half an hour.... it is quite posisble they are badly fouled after the misfiring. You could buy a new set of plugs of course, but you wouldn't get to the look on the face of HID Quote Link to comment Share on other sites More sharing options...
Pwyll Posted January 13, 2011 Author Share Posted January 13, 2011 Mr. Fridge - not excessivly so, will have a good sniff next time I try to get it going. Mr. Bowie - going to take that route when I get in from work tomorrow. And as for looks from HID, its my bleedin' oven, in my bleedin' house that I do all the cooking in so she will just have to cope. ;-) Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 13, 2011 Share Posted January 13, 2011 Reason for asking is that if the ECU can't see the pulses from the coil -ve (white/black or white/blue wire) then it won't fire the injectors. Quote Link to comment Share on other sites More sharing options...
Pwyll Posted January 15, 2011 Author Share Posted January 15, 2011 Reason for asking is that if the ECU can't see the pulses from the coil -ve (white/black or white/blue wire) then it won't fire the injectors. Hmmm, food for thought. Assuming that the pulse is there at the coil, is there anyway I can check if it is making its way back to the ECU? Ta, Paul P.S. Plugs baking on gas mark 6 as we speak. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 15, 2011 Share Posted January 15, 2011 Hmmm, food for thought. Assuming that the pulse is there at the coil, is there anyway I can check if it is making its way back to the ECU? Multimeter with continuity buzzer is the easiest. Flapper EFI: Hotwire EFI: Quote Link to comment Share on other sites More sharing options...
Pwyll Posted January 15, 2011 Author Share Posted January 15, 2011 Problem solved. I hope. It would appear that I have been barking up the wrong tree on this one. When I tested that there was fuel present there must have been residual pressure in the line that caused fuel to squirt from the schraeder valve. So, up with the boot carpet that only got put back last week after having a new floor put in. (Yes, I suspect there is a connection between the two events too.) No power is getting to the fuel pump. There is power at the fuse box in the engine bay, but not at the connector at the top of the tank. So there is a break / dodgy connection somewhere that has been making and breaking depending on what direction the dog farts. Sods law dictates that we didn't ascertain this fact until half past five this evening. So rather than go to a trial tomorrow I am going to be finding the break or running a new cable from the fuse box to the top of the tank. But at least I don't have to cycle to work three o'clock Monday morning. Thanks Fridge and Bowie for your input. All information worth retaining. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2011 Share Posted January 15, 2011 If the wiring loom is anything like an RRC, you will find a round 3 pin multiplug at the nearside rear light, this runs off to the fuel pump, pretty bad place for a connector so I would clean this out and try again....There's an earth bolted to the chassis too, this goes between fuel pump and 2nd from back chassis crossmember, worth checking I say.... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 15, 2011 Share Posted January 15, 2011 Worth noting the ECU will not power the fuel pump up until it sees the pulses from the coil. I think hotwire may prime the pump as the ignition comes on, but flapper doesn't (and has a switch in the airflow meter to energise the pump). Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2011 Share Posted January 15, 2011 Yup, hotline does prime the pump Quote Link to comment Share on other sites More sharing options...
Pwyll Posted January 16, 2011 Author Share Posted January 16, 2011 Me again! We have had it running this afternoon, but particularly well. It will run and drive, but there is no power there. Try accelerating hard and she struggles. Timing is set at 6 deg BTC, which is where it was originally due to the LPG system. My assumption is that the ECU is getting the -ve pulse from the coil as the injectors are running. There is no power getting to the 3 pin multiplug that is fixed under the boot floor on the n/s corner. I am suspicious that this may mean that the ECU is getting the pulse from the coil, but not switching the fuel on. Which I assume means that ECU is fubarred. If this is the case, what kind of beer tokens should I expect to have to part with for an ECU? But I'm guessing that it wouldn't be as simple as just unplugging one and plugging the new one in. We have, for now, by-passed the ECU by running a switched and fused line from the fuel pump fuse in the engine bay fuse box. You say that the ECU primes the pump when the ignition is switched on if its a hotwire, which mine is. Does the ECU control the flow ofthe pump while the engine is running, or does it just turn it on and off again when the ignition is turned off? Any input gratefully received as the box of Swan Vesta is getting an ever likely prospect. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 16, 2011 Share Posted January 16, 2011 The ECU (expensive) controls the fuel pump via the magic of a relay (cheap) so check that first. ECU's rarely go wrong themselves, but are often changed out as people can't work out the root cause of a lot of faults. The ECU switches the fuel pump relay (21) on by grounding the blue/purple wire from it, the 12v supply arrives on the white/slate wire from the multiplug and departs to the fuel pump on the white/purple wire. Notably the fuel pump fuse (fuse 18) is on the output side (after the relay) so fuse 18 is a very easy place to check for 12v when the engine is running. After the priming pulse, the ECU shuts the fuel pump down until it sees the engine turning, after that it should remain running all the time the engine is turning. Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted January 17, 2011 Share Posted January 17, 2011 If you are getting low fuel pressure then either the pump is stuffed (or runing slow-check the power) or the pressure regulator on the back of the engine is bust. You can check the pressure at the schreader valve if you are brave. Quote Link to comment Share on other sites More sharing options...
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