'Dirty' gas strikes!.. or does it?

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mak-uk
Posts: 288
Joined: Mon Sep 03, 2007 8:48 pm
LPG System: Prins VSI
Car: BMW 540iA Sport
Location: All over the UK

'Dirty' gas strikes!.. or does it?

Post by mak-uk » Wed Oct 22, 2008 3:30 pm

Hi

The car is back with Alternatech for a stalling issue when switching over to gas for the first time in the day. They report that 'the reducer is completely bunged up internall with dirty gas'. They are to remove, strip, rebuild with a new reducer repair kit and resassemble.

I have had the problem for several months but never attributed it to 'dirty' gas - I just thought it was a software/tuning issue.

This is my first experience of 'dirty' gas - has anyone suffered due to this? Is this a warranty or cost repair?

Regards.
Mak
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

mak-uk
Posts: 288
Joined: Mon Sep 03, 2007 8:48 pm
LPG System: Prins VSI
Car: BMW 540iA Sport
Location: All over the UK

Re: 'Dirty' gas strikes!

Post by mak-uk » Wed Oct 22, 2008 5:43 pm

Well, just received my answer from Alternatech:
David wrote: Hi Mak

They are not a component failure, its the result of crap lpg that you have been sold so unfortunately you will have to pay.
So that's £20 in parts and 1.5 hrs labour :cry:
Mak
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

jabba
Posts: 25
Joined: Sat Nov 24, 2007 10:34 am

Re: 'Dirty' gas strikes!

Post by jabba » Thu Oct 23, 2008 3:13 pm

Sorry to hear about your problem Mak. Not sure if I've suffered from dirty gas but I do suffer from stalling but I can assume that since Alternatech have not been able to identify my stalling problem then it can't be the reducer in my case.

Hopefully your problem will be rectified but I guess we are at the mercy of the gas suppliers as to whether it's up to scratch or not :(

mak-uk
Posts: 288
Joined: Mon Sep 03, 2007 8:48 pm
LPG System: Prins VSI
Car: BMW 540iA Sport
Location: All over the UK

Re: 'Dirty' gas strikes!

Post by mak-uk » Fri Oct 24, 2008 12:16 pm

Hi Jabba,

From what I remember your stalling problem was when running and quite random? My problem is different in that:

1. It appeared about 6-9 months into the install.

2. It can be easily spotted by starting the car from cold and letting it idle until it is attempting to switch over to LPG.. at which point, it will stall.

Anyway, I managed to negotiate 1/2 an hour off the labour so the bill came to:

45.00 Labour
20.99 Reducer Repair Kit
+ vat
=77.54

However, the problem is still NOT solved. Just after collecting my car and pulling out on to the main road, I let it idle until it attempted to switch over and it stalled again. Here's a video I filmed earlier:

Stalling VIDEO

David from Alternatech states that the reducer rebuild was still needed as it was showing as running high pressure and "would have eventually stopped it running on gas". Clearly, they took no notice of the note left in the car (and handed to them) detailing how to replicate the problem (i.e. number 2 above). :roll:

David is in Europe at the moment and I may be out of the country for a while so will post what happens next as and when it does.

Unbiased Autogas...
Mak
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

runningoldcars
Posts: 47
Joined: Thu May 22, 2008 10:12 pm

Re: 'Dirty' gas strikes!.. or does it?

Post by runningoldcars » Fri Oct 24, 2008 10:23 pm

I use LPG from heavily frequented suppliers, 1.because it's handy & 2.if petrol and diesel pump quality is anything to go buy then generally an oft used tank and pump tends to have less plaque and build up than a little backwater place that pumps 10 gallons a day. That may be a consideration.

Tank pick up mesh clogged?
If it was dirty fuel then the tank filter would have some evidence, however only by removing the valve block (and losing all your gas in a very unfriendly manner) will you find out.

Dirty injectors perhaps?
Dirty injectors will show up with the old plug check - very white and you are lean. Hopefully you would see a variance in plug colours from white to light caramel and this would show the culprits.

Dirty HE filter?
Evidence would be dirt and build ups on the heat exchanger's paper filter

Clogged gas distributor manifold/block?
If like mine you have a little manifold that is used as a feeder to the injectors it may have some clogging. Certainly the ports in mine are small.

Gas manifold to injector pipes?
If you have flexible pipes that run from the gas manifold to the injectors they may be clogged, pinched, or even heat soaked and sticky inside making them swell.

Damaged fuel pipe under the car?
If you have metal pipe running under the car for the fuel feed then you may have kinked of pinched it on something unwittingly and gas is not getting to the front end.

Sticky gas release solenoid(s)?
The safety solenoids at the tank and/or front end may be sticky and not letting gas through.
You could maybe even check the circuit that controls them in case of short or broken connection.

As part of the diagnosis, if possible, hook a computer to the gas ecu and get an assistant to watch lambda and injector pulse signals to see what is happening in the run up to the stall conditions.
I can't say what you'd be looking for but you may get clues from pre-switchover and switchover behaviour.


You may also want to check your front fog lamps..............
____________________________________________________________________________________________
RunningOldCars

Honda Accord Coupe, 2.0l, 4spd automatic, Aldesa RSI+ lpg kit, Steely Dan's 'Katy Lied' on stereo.

mak-uk
Posts: 288
Joined: Mon Sep 03, 2007 8:48 pm
LPG System: Prins VSI
Car: BMW 540iA Sport
Location: All over the UK

Re: 'Dirty' gas strikes!.. or does it?

Post by mak-uk » Sat Oct 25, 2008 10:52 am

Thanks ROC.

However, as the system is under it's warranty period, I cannot really tinker with it but have to leave it all to them.

I guess it could be any of those things you have described but wouldn't they show up under regular driving and not just when switching from petrol to LPG at idle.

Front fog lamps :?: Oh yes, they are cracked... plastic on the the E39 sport models and keep getting cracked by motorway driving!
Mak
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

tucker
Posts: 12
Joined: Fri Mar 28, 2008 12:58 am

Re: 'Dirty' gas strikes!.. or does it?

Post by tucker » Sat Oct 25, 2008 9:34 pm

Hi Mak

Over the last week, I've had a similar problem that only happens on first LPG switch over of the day. It runs fine after and I was associating it to the colder weather. I have upped the switch over temp on the software, but no improvement.

It starts fine and goes normal on petrol first thing. Mine doesn't stall, but it runs lumpy as though a coil has gone. The engine light flashes and gives an error code showing a mis-fire on the 4th cylinder. If I switch back to petrol it still runs the same. I have to stop, turn off and restart. It will then go over to gas ok. It's never done this before.

It's a bit weird. I am 9 months into an install, but the fitter has packed in!

I am therefore wondering if it could be dirty filters. I have done about 10k on gas.

mak-uk
Posts: 288
Joined: Mon Sep 03, 2007 8:48 pm
LPG System: Prins VSI
Car: BMW 540iA Sport
Location: All over the UK

Re: 'Dirty' gas strikes!.. or does it?

Post by mak-uk » Sun Oct 26, 2008 10:58 am

Hi Tucker,

Well, Mark J has reminded me that a lot of systems (even modern sequential multi-point) change-over at a certain RPM; so I am not sure if the Prins VSI system needs to be revved at idle to switch over or not. I think it doesn't but I need to confirm this. However, your system might so an idle switchover test might not be the best thing.

I always take LPG from frequently used pumps. My filter was changed a few months ago and this reducer rebuild hasn't helped so will see what happens. It might be worth changing your filter as you said?

I suggest you contact the distributors of your system to see if there is anyone else you can take it to whilst it's under the warranty.
Mak
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

tucker
Posts: 12
Joined: Fri Mar 28, 2008 12:58 am

Re: 'Dirty' gas strikes!.. or does it?

Post by tucker » Sun Oct 26, 2008 10:03 pm

Hi Mak

Yes I can take it to the distributer which is about 35 miles away, which I will if needed.

Mine was set to change over at a set temp. Since the problem I've altered the software so it only changes when over 2000 revs, but it didn't really change anything.

I drove 200 miles in it yesterday and this morning it didn't do it, but I was driving downhill when it changed. I'll see how it goes. Good luck.

peakcruiser
Posts: 1
Joined: Wed Mar 04, 2009 2:37 pm
LPG System: multi point sequenti
Car: pt cruiser

Re: 'Dirty' gas strikes!.. or does it?

Post by peakcruiser » Wed Mar 04, 2009 2:50 pm

Hi I recently (end Jan 09) had an experience with so called dirty gas. Car was running rough and not switching over to gas. Took it in to the fitter who said the solenoid was clogged with dirty gas. It cost me £150 notes to correct. The cars been converted for a year and had just paid for itself & was starting to show real savings. After about 4 weeks the same thing is happening and the car is going in for repair AGAIN!

I have also experienced the cold change over difficulty & the problem of stalling on cold mornings when the equipment tried to switch gas onto a cold engine with the resultant stalling. This took 3 visits to get sorted.

To be honest I wouldn't recommend a conversion to anyone - it really isn't worth it:
- £1600 to ocnvert it - you need to do a lot of miles to recoup any savings
- Stalling - car went in 3 times before it was right - incurring train fares & inconvenience
- Sticky gas - car now been in 2 times - costing money each time
- Difficulty obtaining fuel - frequently garages are out of gas or pumps aren't working - especially on the M1

I'll be selling my car once I've got it fixed and switching to an economical petrol car that works! Am I alone with this cynical view or have others experienced constant difficulties?

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