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[Robski]

Right here goes,I have just had 3ltr cams and inlet plate fitted to my 2.5 since they have been fitted if I get giddy with the right foot the LPG shuts off and starts running on petrol,so visited a LPG installer to see why the gas keeps shutting off told him what had been done and he says that the gas is underfueling due to the 3ltr cams and that I need to have a remap of the petrol to suit the cams as the gas reads from petrol ecu.I spoke to DLK yesterday and he told he that was *ollox regarding remapping but was not too sure regarding the gas any help would be appreciated

[Entwood]

Right here goes,I have just had 3ltr cams and inlet plate fitted to my 2.5 since they have been fitted if I get giddy with the right foot the LPG shuts off and starts running on petrol,so visited a LPG installer to see why the gas keeps shutting off told him what had been done and he says that the gas is underfueling due to the 3ltr cams and that I need to have a remap of the petrol to suit the cams as the gas reads from petrol ecu.I spoke to DLK yesterday and he told he that was *ollox regarding remapping but was not too sure regarding the gas any help would be appreciated

No expert on LPG setups .. but my initial guess is that the LPG can't supply enough gas when you are "giving it large" .. probably just needs the vapouriser pressure tweaking up a bit .. but it could be that the injectors are not man enough for the job and need drilling out a wee tad.

A lot will depend on the type of system you have, what injectors are fitted, and what software is used to control it.

There are some pretty good LPG experts on here .. I'm sure one will pass by soon and prove me totally wrong . !!!

[Kevin Wood]

Yep, it is "ollox" because the petrol ECU bases its' fuelling on what airflow the MAF sensor is seeing. A small increase from a cam change it will cope with without any remapping.

It could be, however, that the LPG system is not able to cope with the increased fuel demand. The question is: why does it revert to petrol? Normally due to low vapour pressure which could mean the system can't deliver fuel fast enough or it could also be down to (or contributed by) a partially blocked filter or vapouriser.

The petrol side of things certainly doesn't need any attention though.

Kevin

[Robski]

Yep, it is "ollox" because the petrol ECU bases its' fuelling on what airflow the MAF sensor is seeing. A small increase from a cam change it will cope with without any remapping.

It could be, however, that the LPG system is not able to cope with the increased fuel demand. The question is: why does it revert to petrol? Normally due to low vapour pressure which could mean the system can't deliver fuel fast enough or it could also be down to (or contributed by) a partially blocked filter or vapouriser.

The petrol side of things certainly doesn't need any attention though.

Kevin

Cheers Kevin thats what DLK was saying regarding the petrol but wasnt sure regarding gas,my LPG system is a BRC sequential 

[Marks DTM Calib]

Petrol ECU as already said, needs no changing.

The LPG might not e delivering the gas requried and is doing the correct thing b resorting to petrol at uber revs and wide throttle, I assume it detects max LPG injector duration and reverts based on that.

Sounds to me like you need to avoid this guy like the plague as he clearly is lacking a good grasp of the basics of even the LPG operation let alone the Petrol one!!

[Robski]

Petrol ECU as already said, needs no changing.

The LPG might not e delivering the gas requried and is doing the correct thing b resorting to petrol at uber revs and wide throttle, I assume it detects max LPG injector duration and reverts based on that.

Sounds to me like you need to avoid this guy like the plague as he clearly is lacking a good grasp of the basics of even the LPG operation let alone the Petrol one!!

I take it you mean the gas man an not DLK

[Kevin Wood]

I take it you mean the gas man an not DLK

Probably wise to avoid both, for different reasons. 

The former'll completely Roger your car if given half the chance and ... 

 

kevin

[Robski]

I take it you mean the gas man an not DLK

Probably wise to avoid both, for different reasons. 

The former'll completely Roger your car if given half the chance and ... 

 

kevin

Im aware of DLK best to not let him pass behind you

[Lazydocker]

BRC is one of the better makes of LPG... Should be able to cope really, especially as the actual difference is not that big in the grand scheme of things

I bet it just want re-mapping, although it may benefit from having the injectors enlarged slightly

[Darth Loo-knee]

BRC is one of the better makes of LPG... Should be able to cope really, especially as the actual difference is not that big in the grand scheme of things

I bet it just want re-mapping, although it may benefit from having the injectors enlarged slightly

Re Mapping is what this bloke mentioned that Rob needed to the tune of £800

[Lazydocker]

BRC is one of the better makes of LPG... Should be able to cope really, especially as the actual difference is not that big in the grand scheme of things

I bet it just want re-mapping, although it may benefit from having the injectors enlarged slightly

Re Mapping is what this bloke mentioned that Rob needed to the tune of £800

WTF

It's a 10 minute job at most!

Rob... Does it do it with a full tank of Gas too or just when part used?

[Darth Loo-knee]

BRC is one of the better makes of LPG... Should be able to cope really, especially as the actual difference is not that big in the grand scheme of things

I bet it just want re-mapping, although it may benefit from having the injectors enlarged slightly

Re Mapping is what this bloke mentioned that Rob needed to the tune of £800

WTF

It's a 10 minute job at most!

Rob... Does it do it with a full tank of Gas too or just when part used?

£80 a minute sounds very good money then

[Martin_1962]

Right here goes,I have just had 3ltr cams and inlet plate fitted to my 2.5 since they have been fitted if I get giddy with the right foot the LPG shuts off and starts running on petrol,so visited a LPG installer to see why the gas keeps shutting off told him what had been done and he says that the gas is underfueling due to the 3ltr cams and that I need to have a remap of the petrol to suit the cams as the gas reads from petrol ecu.I spoke to DLK yesterday and he told he that was *ollox regarding remapping but was not too sure regarding the gas any help would be appreciated

This is what has happened

You have changed the engine characteristics, it is now around 190bhp, the kist was set up with a 170bhp engine.

At full throttle and high revs the gas injectors cannot open long enough to inject enough gas to run safely, so it drops to petrol.

Would need a little more than a remap, possibly upping the pressure, possibly boring out the LPG nozzles, or setting the kit to drop to petrol at over 5500rpm.

6mm bore pipe seems to have a limit of about 200bhp, hence Kevin using 8mm.

I need to remap mine since recamming, but am tempted to replace the vapouriser as mine is knackered

[Entwood]

Right here goes,I have just had 3ltr cams and inlet plate fitted to my 2.5 since they have been fitted if I get giddy with the right foot the LPG shuts off and starts running on petrol,so visited a LPG installer to see why the gas keeps shutting off told him what had been done and he says that the gas is underfueling due to the 3ltr cams and that I need to have a remap of the petrol to suit the cams as the gas reads from petrol ecu.I spoke to DLK yesterday and he told he that was *ollox regarding remapping but was not too sure regarding the gas any help would be appreciated

This is what has happened

You have changed the engine characteristics, it is now around 190bhp, the kist was set up with a 170bhp engine.

At full throttle and high revs the gas injectors cannot open long enough to inject enough gas to run safely, so it drops to petrol.

Would need a little more than a remap, possibly upping the pressure, possibly boring out the LPG nozzles, or setting the kit to drop to petrol at over 5500rpm.

6mm bore pipe seems to have a limit of about 200bhp, hence Kevin using 8mm.

I need to remap mine since recamming, but am tempted to replace the vapouriser as mine is knackered

Not a problem with your description at all .. I agree with it in fact .. but the OP said he had a BRC Sequential system .. and AFAIK they are fully capable of much higher HP ..  I have a BRC Seq on mine and it handles 217 HP without a hitch ...

I just wonder WHICH BRC system he has ... ??  might give us some clues ??

[Robski]

Right here goes,I have just had 3ltr cams and inlet plate fitted to my 2.5 since they have been fitted if I get giddy with the right foot the LPG shuts off and starts running on petrol,so visited a LPG installer to see why the gas keeps shutting off told him what had been done and he says that the gas is underfueling due to the 3ltr cams and that I need to have a remap of the petrol to suit the cams as the gas reads from petrol ecu.I spoke to DLK yesterday and he told he that was *ollox regarding remapping but was not too sure regarding the gas any help would be appreciated

This is what has happened

You have changed the engine characteristics, it is now around 190bhp, the kist was set up with a 170bhp engine.

At full throttle and high revs the gas injectors cannot open long enough to inject enough gas to run safely, so it drops to petrol.

Would need a little more than a remap, possibly upping the pressure, possibly boring out the LPG nozzles, or setting the kit to drop to petrol at over 5500rpm.

6mm bore pipe seems to have a limit of about 200bhp, hence Kevin using 8mm.

I need to remap mine since recamming, but am tempted to replace the vapouriser as mine is knackered

Not a problem with your description at all .. I agree with it in fact .. but the OP said he had a BRC Sequential system .. and AFAIK they are fully capable of much higher HP ..  I have a BRC Seq on mine and it handles 217 HP without a hitch ...

I just wonder WHICH BRC system he has ... ??  might give us some clues ??

Sequent 56 looking at the lpg system info book that was given on install