simonr Posted December 10, 2006 Share Posted December 10, 2006 The engine will start and run for about a minute (hot or cold). It will then start to stumble. If you increase the throttle, it will run fine for a second , stop firing for a similar period then, so long as it is still rotating fire & run for another second. This goes on, getting worse for ten sec then it stops. You can re-start it almost immediatly (say 30 sec) and it does the same. This happens of Petrol or LPG. Ignition looks OK - plenty powerful spark. The only thing I've noticed is that as it starts to stumble, the mixture goes quite rich - although this could easily be a symptom of not firing rather than the cause. Also, it is much harder to start on either fuel than it was a week ago. Once running, air/fuel ratio looks OK - until the above! Any thoughts? (other than helpful "buy a diesel" ones) Cheers, Si Quote Link to comment Share on other sites More sharing options...
selectcase Posted December 10, 2006 Share Posted December 10, 2006 Could be the water tempature sensor - if it goes wrong it can send the ecu/afm the wrong signals and mess up the mixture - quite easy to replace and not too expensive Quote Link to comment Share on other sites More sharing options...
selectcase Posted December 10, 2006 Share Posted December 10, 2006 or the amplifier on the distributor or the afm - try disconnecting it - it should run worse Quote Link to comment Share on other sites More sharing options...
istruggle2gate11 Posted December 10, 2006 Share Posted December 10, 2006 I was looking at this website last night, perhaps symptom 4 is like yours? Its a bit of a weak and comercialised site, but might help? Quote Link to comment Share on other sites More sharing options...
jwriyadh Posted December 10, 2006 Share Posted December 10, 2006 At first glance appears to be ignition system related. How do you generate your spark? Have you used a timinglight to observe whether the spark is present while engine is not firing? The regularity of the problem suggests an amplifier with short-term overheating. Are there any common parts to petrol/LPG control or paths? Just thinking about air supply as well. jw Quote Link to comment Share on other sites More sharing options...
GBMUD Posted December 10, 2006 Share Posted December 10, 2006 I would have guessed condenser. But IIRC you are on electronic ignition.... Chris Quote Link to comment Share on other sites More sharing options...
simonr Posted December 10, 2006 Author Share Posted December 10, 2006 The fact that it happens on petrol or gas tends to rule out fueling problems, unless it's a mechanical problem with the plenum or something like that. The EFI is Megasquirt - which has been helpful, plug in laptop & see more of what it's up to. LPG has no electronics, it's just a venturi mixer. I run electronic ignition - so no condenser. I'll try a different amp, just in case. There appears to ba a spark right up until the last revolution of the engine. It could be that the timing is changing dramatically at the end I suppose. Thanks for the suggestions - any more welcome! Si Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted December 10, 2006 Share Posted December 10, 2006 The fact that it happens on petrol or gas tends to rule out fueling problems, unless it's a mechanical problem with the plenum or something like that. It could be a sensor that both fuel systems use? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted December 10, 2006 Share Posted December 10, 2006 The fact that it happens on petrol or gas tends to rule out fueling problems, unless it's a mechanical problem with the plenum or something like that.The EFI is Megasquirt - which has been helpful, plug in laptop & see more of what it's up to. LPG has no electronics, it's just a venturi mixer. I run electronic ignition - so no condenser. I'll try a different amp, just in case. There appears to ba a spark right up until the last revolution of the engine. It could be that the timing is changing dramatically at the end I suppose. Thanks for the suggestions - any more welcome! Si Whats the fuel pressure doing, pump or PRV, or does this mean it can't be due to GAS as well ? Plugs ? another possibility Nige Quote Link to comment Share on other sites More sharing options...
simonr Posted December 11, 2006 Author Share Posted December 11, 2006 Solved it - at least in part! Nick (Rogue Vogue) said to me last night "Are you sure it's not just a coincidence that it behaves the same on gas & petrol" I was sure at the time - but it turns out he was right. Well done Nick - have a star! On Gas at least, the hose which supplies water from the cooling system was kinked. That meant that the vaporiser was freezing and the flow of gas stopping. It was taking a minute or so to freeze, but de-frosting almost immediatly. It only manifested itself this week because the temperature has dropped. No idea what's happening on petrol yet - but it's something different! Si Quote Link to comment Share on other sites More sharing options...
simonr Posted December 11, 2006 Author Share Posted December 11, 2006 Doh..... Guess what the problem was on Petrol? It had run out! Si Quote Link to comment Share on other sites More sharing options...
GBMUD Posted December 11, 2006 Share Posted December 11, 2006 Only you... Gimp! Chris Quote Link to comment Share on other sites More sharing options...
headhunter Posted December 11, 2006 Share Posted December 11, 2006 Doh.....Guess what the problem was on Petrol? It had run out! Si All clever people have an achillies heel, your's Simon appears to be that you miss the obvious John Quote Link to comment Share on other sites More sharing options...
nas90 Posted December 11, 2006 Share Posted December 11, 2006 Doh.....Guess what the problem was on Petrol? It had run out! Si Simon, the next time I make a cock-up and you give me the "what a blithering idiot look" ......................... Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted December 11, 2006 Share Posted December 11, 2006 Oops ! Mo Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted December 11, 2006 Share Posted December 11, 2006 Oh no.... Not something I had considered... (And this guy wants up to buy fantastic hi-tech solutions from him !!!) So glad to hear you found a solution.... Quote Link to comment Share on other sites More sharing options...
jwriyadh Posted December 11, 2006 Share Posted December 11, 2006 Simon, longer or more tea/coffee/beer/ciggie breaks. Helps to break out of tight loops and think sideways. jw Quote Link to comment Share on other sites More sharing options...
trainspotter Posted December 11, 2006 Share Posted December 11, 2006 yup buy a diesel. works every time for me!!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
RocKeR Posted December 12, 2006 Share Posted December 12, 2006 All clever people have an achillies heel, your's Simon appears to be that you miss the obvious That's why he once helped to rewire my car so I could jump start it through the cigar lighter before we noticed the gear selector was still in drive! Quote Link to comment Share on other sites More sharing options...
simonr Posted December 12, 2006 Author Share Posted December 12, 2006 That's why he once helped to rewire my car so I could jump start it through the cigar lighter before we noticed the gear selector was still in drive! Wait a moment Mr Electrical Guru Hirst! I didn't notice you in the pub jumping up & down saying "I bet it's the.......". Or anyone else for that matter - only Nick suggesting it might be a coincidence, which could be read as check the obvious I suppose! At least I put my hands up to it! Thanks to all of you for your kind words of support! Si Quote Link to comment Share on other sites More sharing options...
Andy Posted December 13, 2006 Share Posted December 13, 2006 hehehe brilliant fault. reminds me of when i worked in a volvo dealer. demo car died like it was out of fuel, a day later after playing with the computers etc for ages someone took the fuel pump out the tank to find it had no gogo juice. the level sender was stuck on a wire so it showed half a tank Quote Link to comment Share on other sites More sharing options...
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