E30 Zone

Just realised this is in the wrong section could a mod please move this to the technical help section thanks.

Hi all recently had my 318is converted to run on LPG, its a BRC sequent system, done 600miles since install.

Now between 2100 and 3100 RPM it is very hesitant/jumpy/lumpy/ when just cruising e.g. holding the throttle in one position. If you accelerate through this range its not too noticeable.

So far I have reinstalled original chip
Fitted new plugs
Converted to coil on plug ignition
Checked for air leaks
Cleaned ICV
Adjusted CO from 1.5 to 2.5

The Emissions tests they supplied showed

Petrol CO: 2.14%
HC: 249ppm

LPG CO: 0.28%
HC: 736ppm

The car is going back into the converters to be recalibrated, but they said they had never seen this problem before, they are an approved installer.

They say that it does this on petrol as well which I cannot really notice, may be very slightly but could not say for certain.

If any one has any ideas why it runs so crap ? or issues to check would be really happy to hear.

Going to take it back and say either fix it or remove it. System has a 2 year warranty and 1 years labour.

Why wind the CO up?

Also why is the HC so high on LPG?

CO put up as apparently M42 run well at around 3 and the lpg ecu emulates the petrol ecu,

Not sure on the hydrocarbons I believe LPG is inherently high in them. but I am open to differing views.

Cool, just wondered. If Brian Moore sees this he may be able to help

How does your car run on LPG john and what system did you go for, single or multi point

Mine was already converted it is a single point system, very simple but not running quite right at the time i took it off the road 6 months ago. I am rewiring all the lpg kit which i think is one of the main problems

Throw it away! every aftermarket LPG kit I've ever come across has caused more grief than it was ever worth.
I would say the gas system has an air leak somewhere,I presume they've fitted some form of lambda sensor? into the exhaust system...?

No lamber sensor fitted, I did ask about this but they say the system does not work like that.

Well I picked up the car tonight and it is running very well on LPG almost unoticable apart from a reduction in power. So happy it is running smooth now. When i get my new camera I will upload some pictures of the install.

Some pictures of the install.

Filler behind number plate







82 Litre tank



Rear of filler



ECU and Vaporisor



Sequential injector rail



And Coil on Plug conversion to make it run well



If anyone wants more photos or info please ask

i wanna lpg one of my iS's can you do a write up of what is needed, where you have to run pipes etc?

you shouldnt have any noticable reduction in power with the multipoint injection system you have fitted as there are no restrictions introduced, unless you have a catflap backfire valve added (i cant see one)

Hi, I did not install the kit myself but when I get the car up on the ramp I will try to further document/photo where the pipes lie etc. As for loss of power it is not noticeable but due to LPG being of a lesser octane and having more weight in the car, it did initially feel a fraction slower.

bookmarked busy now

Still a good amount of space left in the boot even with the large tank in there. How much did the kit and installation cost?

Definitely shouldn't be any reduction in power. Why should there be?
Won't be any catflap fitted with a multipoint.

bigmace2004 wrote:Hi, I did not install the kit myself but when I get the car up on the ramp I will try to further document/photo where the pipes lie etc. As for loss of power it is not noticeable but due to LPG being of a lesser octane and having more weight in the car, it did initially feel a fraction slower.

Makes me cringe reading things like this (sorry!) LPG has a has a higher octane than pump petrol not lower. If the ignition is tuned to suit and/or the compression is increased, then if anything you should be able to see a increase in power. You however I assume have done neither and so power will be very similar.

Weight however is an issue. My 80litre tank is huge and weighs a ton! I plan to remove the petrol tank and fit a small fuel cell and swirl pot in the spare wheel well to reduce this effect as I rarely run on petrol anyway.

Brianmoooore wrote:Definitely shouldn't be any reduction in power. Why should there be?
Won't be any catflap fitted with a multipoint.

Only thing I can think of is the ignition timing won't be ideal,but not too sure how his LPG ecu works

LPG ECUs don't normally have any control over ignition timing, so it will be less than optimal when running on gas, but ignition timing 'correctors' are available, although in practice, the gains reported by using them have been minimal. The inherent increased efficiency of an engine running on LPG should be enough to counteract ant small timing related losses anyway.
An empty LPG tank may be much heavier than a petrol one, but 60 litres of LPG weighs considerably less than 60 litres of petrol, so the weights of full tanks won't be much different.

bigmace2004 wrote:No lamber sensor fitted, I did ask about this but they say the system does not work like that.

The LPG system copies the petrol injection duration times, based on a compensating map, however, with no lambda your petrol ECU is not compensating for the actual burn conditions so inherently both systems are running blind.

By adjusting the LPG compensation 'map' they will be able to tune this out.

Brianmoooore wrote:LPG ECUs don't normally have any control over ignition timing, so it will be less than optimal when running on gas, but ignition timing 'correctors' are available, although in practice, the gains reported by using them have been minimal. The inherent increased efficiency of an engine running on LPG should be enough to counteract ant small timing related losses anyway.
An empty LPG tank may be much heavier than a petrol one, but 60 litres of LPG weighs considerably less than 60 litres of petrol, so the weights of full tanks won't be much different.

true, but in my case (agreed this will not be the same for everyone), i probably have about 5-10 quids worth of petrol in the tank at a time just incase I ever fully run out of LPG or something goes wrong. Pretty large tank for under 10litres worth! A benefit however is the ability to brim the tank though if we have some heavy snow, but nothing a couple of sand bags wouldnt sort out.

That's what I'm saying. It's no good comparing the weight of an empty petrol tank with an empty LPG one - the LPG one will be many times heavier than the petrol tank. Put 50 litres of fuel in each, and the extra density of the petrol will have evened things up a little - by about 12Kg.

What steering rack are you running?

bigmace2004 wrote:Some pictures of the install.

Filler behind number plate

Love this, very discrete. My 318is runs on LPG too but the system is 10 years old and could probably do with a tune. Overall it runs well but there are several little niggles I should sort out.

Filler behind number plate, very cool shame i can not do that on touring

Ok so reading the posts i feel that the car is slighlty less responsive than before, i have now rembered that i put the orginal chip back and i feel this is the reason for this.

I am enjoying the LPG cost savings and I am getting exaclty 400 miles to £45 worth of lpg vs 280 miles to £60+ of petrol. LPG locally is 76 p per litre. I need to cover 15000 miles to recoup the install cost.

I like the idear of running a reduced sized petrol tank and will look into that this year. I only keep around 15 litres of petrol in there for starting/emergencys.

The car does not retain its orginal handling caterstics and is not as fun although certainly not a boring daily commutor. I am thinking about fitting some stiffer rear spings may be convertable ones.

The car has an e46 stering rack fitted. The filler behind number idear i got from someone on the zone it is good but you do have to attach the filling nozzle upside down and takes a little getting used to.

I want to get 400 miles for £45!!

On my 2.0 touring i get about 230 miles for £45.. is there something wrong with my setup maybe??

Might have to start a new thread.

kislam wrote:I want to get 400 miles for £45!!

On my 2.0 touring i get about 230 miles for £45.. is there something wrong with my setup maybe??

Might have to start a new thread.

If you have LPG then yes theres a problem.