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Folks,
I really need to properly diagnose the cold start issues I've been getting recently. I suspect it's related to fuel pressure leaking away overnight but my fuel pressure gauge doesn't have an attachment that fits onto the valve at the back of the fuel rail.
Does anyone have any recommendations please? Preferably something cheap :)
Thank you!

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I just use a tyre pressure gauge..... I know getting at the port on a Thor isn't easy but if you find one that will fit, go for that. A pressure gauge is a pressure gauge, it will show pressure of a liquid or a gas (or air) just the same.

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Isn't it a screw fit? It certainly feels like it. Standard pressure gauges are normally push on.

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It's a Schrader valve, just the same as on your tyres. So can be a screw fit, a push on or one of those strange things with the locking lever.

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When you turn on the key, the pump should run for about 3 seconds to pressurise the system./ Try turning it on and waiting a few seconds before cranking.

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Does is still struggle to start on a morning if you run it on petrol for a while before turning the engine off? If gas leaks into the inlet manifold when the engine is off then when you come to start it the engine gets petrol and LPG instead of petrol and air, such leak is sometimes caused by a leaking LPG pressure reducer diaphragm or LPG injector.

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Marshall8hp wrote:

When you turn on the key, the pump should run for about 3 seconds to pressurise the system./ Try turning it on and waiting a few seconds before cranking.
Interesting, mine doesn't run on the key - only on crank.
I run the pump using the Nanocom and it takes 1-2 full cycles (about 15 seconds) to pressurise it in the morning.
At least, that's what I think is going on. I need to get a gauge on the rail to be sure :)

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Lpgc wrote:

Does is still struggle to start on a morning if you run it on petrol for a while before turning the engine off? If gas leaks into the inlet manifold when the engine is off then when you come to start it the engine gets petrol and LPG instead of petrol and air, such leak is sometimes caused by a leaking LPG pressure reducer diaphragm or LPG injector.

I suspected that, but I was running on petrol exclusively for a couple of weeks with an empty LPG tank and it didn't change behaviour. If it's LPG related, it's weirder than that :)

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It won't be LPG related then :-)

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As you installed it, that's a relief for you then Simon......

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:D the LPG is ticking along nicely! I'm way over time for a service though, I've never got a free afternoon these days :( and Simon is flat out.
Asda have got some gas too! 72ppl, which beats the hell out of 99.9 or running on p**l

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Gilbertd wrote:

As you installed it, that's a relief for you then Simon......

Haha yes!

Or at least in a way... It would be an easy fix if it were the LPG system causing it, since it isn't the LPG causing it it could be any of dodgy fuel pump, fuel pressure reg, leaky petrol injector, MAF, TPS, etc etc?

@Morat It'll be reet without an LPG service mate, or since the LPG seems to be working OK you could easily change filters yourself?

For a very basic/latent fuel pressure test you don't necessarily need a fuel pressure gauge... Just depress the schraeder valve when it's been stood and see if any fuel squirts out?

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Lol, that's a really good idea thank you. Experience counts!

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Yep, definitely time for a new fuel pump :(
If I turn the fans/radio off and wait for the random noises to finish, I can cycle the fuel pump solenoid with the nano until I can actually the hear the fuel pump running (just). Once it is, she starts first time every time and keeps on rocking until the LPG switches in or even for the rest of the journey if the LPG is empty. I guess it's the electric equivalent of a tap on the fuel pump to get 'er going.

So.... Floor hatch or tank drop? :)

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is there a seperate relay for the pump? worth swapping that to try just incase?

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I haven't bothered yet - I can hear the relay firing every time so I assumed it's the pump. Maybe I should swap the relays round before things get expensive!