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Re: Delayed Start

Posted: Wed Jan 11, 2017 5:31 pm
by LPGC
If you are attempting to start on LPG after the engine last ran on LPG, then if you hear a clunk from the tank or front LPG solenoid when you turn on the ignition (with the LPG switch set to LPG mode), try this... Without cranking the engine, switch the ignition on and off say ten times, so you hear ten clicks from the LPG solenoids, leave a pause of a second before turning off the ignition after each click (so this process should take at least 10 seconds), then try starting the engine on gas. Depending on how your system is set up, this might prime the inlet manifold with a little gas, thus making for a slightly richer mixture at first when you do crank the engine - mixture provided by single point systems can be affected by temperature and with the cold weather you may have a slightly lean mixture until the reducer is warmed up. Or if the mixture was already too rich the clicking could worsen the situation, but I doubt it. Any backfires during attempts to start the engine or driving under any conditions?

If you are attempting to start on petrol after the engine last ran on LPG, then we would expect you to need to crank it for a while before the engine will start because the carb will need to prime with petrol first.

The other 'many things' include someone inadvertently adjusting settings on the reducer, reducer itself in need of servicing or on it's way out, ignition system in need of service, battery or starter motor on the way out, kinks and creases in pipes between reducer and mixer, vacuum leaks, adjustment of that knurled knob. But you're not doing too badly if you can start on gas within 10 seconds this weather, really, anyway.

Post crossed with Gilbert's.

I've been going along the line this will be an open loop system, knurled brass knob on Y connector being the splitter between two mixers on two carbs on flat four engine that combines the flow adjuster. But even if this is the case, there could be a stepper further back in the feed to mixers, but I'd doubt it with this being a carb'd engine.

Simon

Re: Delayed Start

Posted: Sat Jan 14, 2017 12:49 pm
by seventiesandy
Thanks for taking the time to reply. It is a single carb, no electronics from the reducer and once it has fired up there is absolutely no problem, runs very sweetly, which makes me think theres no fuel until the engine has turned over 10 seconds or so.
Unless anyone knows different, our nearest specialist is Hullavington, Chippenham. Spose I need to take it there for dignosis

Re: Delayed Start

Posted: Sat Jan 14, 2017 8:15 pm
by LPGC
No probs Andy, have you tried what I suggested etc?
Simon

Re: Delayed Start

Posted: Sat Jan 14, 2017 8:36 pm
by Brian_H
seventiesandy wrote:Thanks for taking the time to reply. It is a single carb, no electronics from the reducer and once it has fired up there is absolutely no problem, runs very sweetly, which makes me think theres no fuel until the engine has turned over 10 seconds or so.
Unless anyone knows different, our nearest specialist is Hullavington, Chippenham. Spose I need to take it there for dignosis
Would that be Blaze? (Rossko used to post on here from there). If so I think they are no longer about as far as anyone is aware, or not doing lpg at least.

Re: Delayed Start

Posted: Sun Jan 15, 2017 2:11 pm
by seventiesandy
Blaze, yes that rings a bell, or a fire alarm.

Re: Delayed Start

Posted: Fri Jan 20, 2017 2:45 pm
by gascab
I'm no installer, but a very quick 10 second check of voltage drop at the injector +ve wire could rule out a dodgy +ve terminal in the system.

The fact you have 12v at the injector wire's not neccessarily enough, measure the voltage with a digital multimeter directly across the battery terminals then measure the voltage from the injector +ve wire to the negative battery terminal, if there is any difference of more than 0.2v then you may have a continuity problem somewhere, a bad connection!

You can do similar with the systems earth point, and again you should not get aything more than a 0.2v drop.

Ideally the voltage drop should be 0v to 0.05v, providing the system does not have a built in voltage stabliser.

Might help...

Re: Delayed Start

Posted: Fri Jan 20, 2017 9:03 pm
by seventiesandy
Thanks for the advice but the only electric in the system is where the on a valve after the petrol pump which I assume cuts off the petrol supply when the LPG is switched on (the LPG is joined with a y connector onto the fuel pipe just after if I rember right, it is a very old system and very basic

Re: Delayed Start

Posted: Fri Jan 20, 2017 11:11 pm
by Brian_H
seventiesandy wrote:Thanks for the advice but the only electric in the system is where the on a valve after the petrol pump which I assume cuts off the petrol supply when the LPG is switched on (the LPG is joined with a y connector onto the fuel pipe just after if I rember right, it is a very old system and very basic
There would still be a solenoid on the tank to operate the valve on there, and should be another up the front as well near the input to the vaporiser though maybe that one isn't present. Otherwise all the gas in the tank would not be able to be contained when required.

Some photos would help with the diagnosis - if you can get some taken theres a sticky post at the top of the forum showing how to link to them, if your struggling with that bit once you've got the photos taken then drop me a pm or post back here and will work out a way of sharing them with those who can help you.

Otherwise you will be looking for an installer to assist - as said pretty sure Blaze have shut up shop given Rossko hasn't been on here in over a year now, and their website has gone. A single point system could prove a challenge to some installers to fix, so you may have to travel a bit to find someone to look at it.

Re: Delayed Start

Posted: Sat Jan 21, 2017 10:03 am
by seventiesandy
OK I'm in the engine today for service and stuff so I'll take some pics while I'm in there. Very grateful for your help

Re: Delayed Start

Posted: Sat Jan 21, 2017 5:11 pm
by LPGC
You may not have realised that the reason I mentioned turning ignition on and off several times before cranking the engine was because this may make the engine start on first attempt when you do crank it... because this may prime the manifold with a little gas.

Simon

Re: Delayed Start

Posted: Sat Jan 21, 2017 6:54 pm
by seventiesandy
I will try. Thankyou.

Re: Delayed Start

Posted: Wed Jan 25, 2017 6:47 am
by 57jam89
Sounds like my daughter's megane!
It doesn't have lpg and is fully serviced and still sometimes takes 3 trys to start it!

In the last 6 mths it's had new spark plugs, oil air fuel filters and new battery.

Re: Delayed Start

Posted: Wed Jan 25, 2017 4:08 pm
by LPGC
Could be a dodgy crank/cam sensor/temp sensor, dodgy fuel pressure regulator or fuel pump on the Megane Simon? Though depending on year some have ECUs that go dodgy and hold the voltage output from one of the two water temp sensors at a voltage themselves, thus fool themselves into reading incorrect engine temperature... I've fixed one with this symptom by making a separate little circuit which buffers correct sensor voltage to the ECU temp input. Cost only a few quid in bits or an alternative would have been a new ECU costing £700 plus coding.

Simon

Re: Delayed Start

Posted: Wed Jan 25, 2017 9:22 pm
by Gilbertd
57jam89 wrote:Sounds like my daughter's megane!
It doesn't have lpg and is fully serviced and still sometimes takes 3 trys to start it!

In the last 6 mths it's had new spark plugs, oil air fuel filters and new battery.
A girlfriends daughter had a late model 1.2 Clio that was the same. Sometimes would start fine, other times would crank for ages. Did it to me one day when I had taken it to get a pair of tyres fitted so took it round to the workshop of a guy I know. He plugged in a code reader and it came up with a crank sensor error. Reset the code, restarted and the same code popped up again. He reckoned it was a common problem which was confirmed by the Renault dealer (Renault dealer part only) who didn't have any in stock as they had sold out. £20 and a couple of days later I fitted it and the problem had gone, performance was improved too. It was immediately after that I bought my own code reader, invaluable with anything remotely modern.

Re: Delayed Start

Posted: Thu Jan 26, 2017 2:23 pm
by 57jam89
Gilbertd wrote:
57jam89 wrote:Sounds like my daughter's megane!
It doesn't have lpg and is fully serviced and still sometimes takes 3 trys to start it!

In the last 6 mths it's had new spark plugs, oil air fuel filters and new battery.
A girlfriends daughter had a late model 1.2 Clio that was the same. Sometimes would start fine, other times would crank for ages. Did it to me one day when I had taken it to get a pair of tyres fitted so took it round to the workshop of a guy I know. He plugged in a code reader and it came up with a crank sensor error. Reset the code, restarted and the same code popped up again. He reckoned it was a common problem which was confirmed by the Renault dealer (Renault dealer part only) who didn't have any in stock as they had sold out. £20 and a couple of days later I fitted it and the problem had gone, performance was improved too. It was immediately after that I bought my own code reader, invaluable with anything remotely modern.
Cheers but crank senser has also been replaced.
Also no fault codes stored or pending.

Re: Delayed Start

Posted: Thu Jan 26, 2017 2:25 pm
by 57jam89
LPGC wrote:Could be a dodgy crank/cam sensor/temp sensor, dodgy fuel pressure regulator or fuel pump on the Megane Simon? Though depending on year some have ECUs that go dodgy and hold the voltage output from one of the two water temp sensors at a voltage themselves, thus fool themselves into reading incorrect engine temperature... I've fixed one with this symptom by making a separate little circuit which buffers correct sensor voltage to the ECU temp input. Cost only a few quid in bits or an alternative would have been a new ECU costing £700 plus coding.

Simon
Hi Simon.
It's a 2004 1.6 16v.

Re: Delayed Start

Posted: Fri Jan 27, 2017 10:32 am
by LPGC
I'm talking 2004 1.6 16v Citreon... same engine, so same ECU? Apparently the ECU reading incorrect temps is a common fault on them and reading incorrect temp doesn't come up as an OBD fault. Still a long shot it's this but one of the points I mentioned should be the culprit though.

Simon