Spark plugs for LPG LS430

[ScottC]

4 minutes ago, Herbie said:

The guy who did mine really knew his onions and rather than just use a complete kit from a given manufacturer he chose each component as being the best for the car.

It's more than three years since the conversion was done and it's over a year since we traded the car in for our current one and my memory isn't what it used to be but I do know that he chose a KME NEVO ECU, along with (I think) either Keihin or BRC injectors and possibly a KME Gold reducer - I honestly can't remember. What I do know is that it was truly superb and never gave an ounce of trouble.

Sounds good

 

Scott

[Bluesman]

15 hours ago, Herbie said:

Wrong I'm afraid.

Mine would start on LPG from cold although it wasn't really recommended. The actual changeover temperature was set at about 35^oC, which is a long way from normal operating temperature of about 90^oC. Usually it changed within about half a mile.

It's true that older systems should be run up to normal temp first but modern gas systems look after themselves very well on their own.

From http://www.go-lpg.co.uk/Do_I.html                  Do I have to start my car on Petrol?

It is a good idea to always run your engine up to full temperature on Petrol for at least these reasons -
Vaporiser freezing

If you have an LPG system that will allow you to select LPG only (including cold starting) this can be asking for trouble, especially on damp days or during the winter months (or both). The vaporiser may freeze up in seconds if it is not being heated by engine coolant. It is much better to start on Petrol, avoiding any vaporiser icing problems. Switch over to LPG when the engine is fully up to temp. Stick to this and avoid a lot of potential problems! (This effect is more fully described in the item 'Will there be any difference in performance after conversion')

If you start up from cold on gas, the vaporiser is not being heated by engine coolant. There is a refrigerating effect as the gas within it vapourises. It will freeze up and stick, possibly causing weak mixture backfiring or gas leakage. If you run the engine up to temp. on petrol before switching over to gas this cannot occur as the engine coolant will already be hot. Don't be fooled into thinking that the air is too warm for freezing to occur, outside temperatures do not have to be down to freezing level for this to happen. The vapouriser may freeze at temperatures up to + 25 degrees Centigrade, especially if the air is very damp..

Care for your petrol injectors
To put this into context, here's a little analogy -

After cutting hedges, a wise man will clean and oil his garden shears before he puts them away. They will not rust or lose their edge whilst in the shed. They will be ready for the next use, whenever that may be.

A few cases of partially blocked petrol injectors in dual - fuel vehicles have encouraged us to investigate and find the cause.

The problem seems to occur mostly with larger engined cars that have covered a lot of miles before LPG conversion. Later, after running the car on LPG almost exclusively (as you would!) owners have found that petrol operation has become erratic and in one case the vehicle was practically undrivable on petrol, although it ran perfectly on LPG. Much examination showed that the injectors were blocked to the extent that their spray pattern was seriously affected. A miraculous improvement was afforded by the addition of a good quality injector cleaner to the petrol, followed by a few miles of petrol driving.

It appears that a car that has done a lot of miles (and maybe not had its injectors cleaned as often as it might) will have a 'skin' of carbon deposited on the injector heads. Whilst making no immediate difference when running on petrol (of course, all injectors will eventually become blocked if they are not cleaned) this coating can expand and harden when running the engine on LPG. Leaving your petrol injectors dirty and redundant for long periods is likely to cause problems later.

The problem is by no means sure to occur in any particular type of injector, vehicle or engine and the incidence is quite low (in the order of 1% of converted vehicles) but prevention is always better than cure.

OK, we are lucky enough to have our vehicles converted to run on a much less expensive fuel, but we still rely on petrol as a back - up. We want it to work when we do have to use it. To avoid problems altogether, there is a simple and inexpensive measure you can take right now!

Add an injector cleaner to your next tank of petrol (STP, Wynn's and other good brands are recommended) and your injectors will be cleaned up every time petrol is selected. If you are in the good habit of starting up on petrol and running the engine up to temp. before switching over to LPG, you will be preventing this problem from occurring. If you have an LPG system that will not switch over until a pre-determined temp. has been reached, you won't even have to give it a thought!

Someone suggested that the addition of injector cleaner to petrol is a 'hidden' cost of LPG use, one ignored by the conversion industry........

But injector cleaner is designed for use when running on petrol, LPG conversion or not!

The best way to avoid both of the above problems is to select the petrol only position on the first start of the day. If you do this you will be cleaning your petrol injectors and ensuring that the vaporiser will not freeze up.

[Herbie]

That's a lot of quoting for not a lot of information and what is there seems to back up what I said anyway.

Moreover, it seems to be talking about manual switching whereas modern systems have temperature sensor input and changeover when certain parameters are met, taking control out of the driver's hands. To take bits of it:

1 hour ago, Bluesman said:

The vapouriser may freeze at temperatures up to + 25 degrees Centigrade

Which is probably why the KME NEVO ECU changed over at 35^oC and not 25^o.

2 hours ago, Bluesman said:

Care for your petrol injectors [...] found that petrol operation has become erratic and in one case the vehicle was practically undrivable on petrol, although it ran perfectly on LPG. Much examination showed that the injectors were blocked to the extent that their spray pattern was seriously affected. A miraculous improvement was afforded by the addition of a good quality injector cleaner to the petrol, followed by a few miles of petrol driving.

Which is probably why the KME NEVO ECU (and almost all modern systems I would imagine) are set to fire up on petrol, irrespective of engine temperature, and change over after half a mile or so.

[Bluesman]

22 minutes ago, Herbie said:

That's a lot of quoting for not a lot of information and what is there seems to back up what I said anyway.

Moreover, it seems to be talking about manual switching whereas modern systems have temperature sensor input and changeover when certain parameters are met, taking control out of the driver's hands. To take bits of it:

Which is probably why the KME NEVO ECU changed over at 35^oC and not 25^o.

Which is probably why the KME NEVO ECU (and almost all modern systems I would imagine) are set to fire up on petrol, irrespective of engine temperature, and change over after half a mile or so.

That's all settled then, Thanks to Go-LPG for their expert knowledge.

[Herbie]

37 minutes ago, Bluesman said:

That's all settled then, Thanks to Go-LPG for their expert knowledge.

Which we already knew anyway  😁

[Bluesman]

1 hour ago, Herbie said:

Which we already knew anyway  😁

Hi Herbie, I was replying to ScottC who said  "No that is completely wrong"  I was pointing out to him that I was correct and providing him with text from the experts at Go-LPG.

 

[LexusPartsDirect]

On 3/13/2019 at 7:31 AM, Abid221 said:

Hello

Getting my LS430 LPG converted. I've read that the spark plugs should be changed. 

Which ones do members recommend? And also how often should they be changed? 

Also do I really need to install the Flash lube system? 

Thanks 

Would you like me to price up the genuine ones for your vehicle? If so PM me your reg of fill in the enquiry form (We beat main dealers) 

https://www.lexuspartsdirect.co.uk/contact-us-genuine-lexus-parts/

[messi]

I got denso irridum sparkplugs from rock auto, took about 3 to 4days for delivery all for £37 odd pounds for all 8. But you can also use NGK irridum sparkplugs which may be a little cheaper. I even got some for a friend's Porsche cayenne 

[Abid221]

7 hours ago, LexusPartsDirect said:

Would you like me to price up the genuine ones for your vehicle? If so PM me your reg of fill in the enquiry form (We beat main dealers) 

https://www.lexuspartsdirect.co.uk/contact-us-genuine-lexus-parts/

Will do. Thanks 

[ScottC]

On ‎3‎/‎19‎/‎2019 at 7:05 PM, Bluesman said:

All LPG engines start from cold on petrol and don't switch over to LPG untill engine has reached operating temp.

Hi

Maybe of interest.

Ford were making cars 13 years ago with LPG engines which started from cold on LPG and then ran on LPG, they didn't have a petrol tank.

https://www.carsguide.com.au/car-reviews/all-gassed-up-9171

 

Scott