Engine Trouble With Lpg Conversion

[Svee]

Hi all,

I know LPG conversions are not all that common but i thought i would ask this question anyway as i am at the end of my teather and if anyone can be of any help i would be forever greatful.

I own a 2000 W reg Avensis SE with a Landi-Renzo LPG conversion already fitted when i bought it from my local Toyota dealer.

When i bought it i used the gas twice. Once to got to London (about 60 miles) and once to go to the shops (mile and a half) and the gas packed up on me. When i pressed the accelerator the engine stalled.

I sent it back to Toyota and they had a good look at it and said there was nothing wrong.

I took the car back, used the gas once and again it packed up doing exactly the same thing so Toyota kindly took it back again and had a look and couldnt find anything wrong. They did tell me i might be switching over to gas wrongly and showed me a procedure to do as i didnt get any documentation with regards to the gas at all.

Basicly they told me to start the car on petrol, wait 30 seconds, switch to gas (green flashing light on the switch), bring the revs up to 2 and a half and leave it there until there is a click and the green led stops flashing and goes steady.

This worked to switch over to gas a couple of times but i have just tried to drive using it and the damn thing is busted again.

as soon as i let go of the accelerator pedal the engine stalls :censor:

Its a shame cos i love my Avensis, i think its a great car but i am almost at the piont of asking Toyota to take it back and give me another car, that is if i am within my rights to do so, as i have only had the car for about 6 months and it looks like im going to be having this problem till the warranty runs out lol

If anyone out there can possibly shed some light on what might be going on here or if im being a muppet and doing something wrong PLEASE tell me.

Thanks in advance for any help on this,

Alan.

[ndsblack]

Hi all,

I know LPG conversions are not all that common but i thought i would ask this question anyway as i am at the end of my teather and if anyone can be of any help i would be forever greatful.

I own a 2000 W reg Avensis SE with a Landi-Renzo LPG conversion already fitted when i bought it from my local Toyota dealer.

When i bought it i used the gas twice. Once to got to London (about 60 miles) and once to go to the shops (mile and a half) and the gas packed up on me. When i pressed the accelerator the engine stalled.

I sent it back to Toyota and they had a good look at it and said there was nothing wrong.

I took the car back, used the gas once and again it packed up doing exactly the same thing so Toyota kindly took it back again and had a look and couldnt find anything wrong. They did tell me i might be switching over to gas wrongly and showed me a procedure to do as i didnt get any documentation with regards to the gas at all.

Basicly they told me to start the car on petrol, wait 30 seconds, switch to gas (green flashing light on the switch), bring the revs up to 2 and a half and leave it there until there is a click and the green led stops flashing and goes steady.

This worked to switch over to gas a couple of times but i have just tried to drive using it and the damn thing is busted again.

as soon as i let go of the accelerator pedal the engine stalls  :censor:

Its a shame cos i love my Avensis, i think its a great car but i am almost at the piont of asking Toyota to take it back and give me another car, that is if i am within my rights to do so, as i have only had the car for about 6 months and it looks like im going to be having this problem till the warranty runs out lol

If anyone out there can possibly shed some light on what might be going on here or if im being a muppet and doing something wrong PLEASE tell me.

Thanks in advance for any help on this,

Alan.

←

Hi,

Personally with the lean burn engines produced by toyota I would recommend getting the engine past cold start .In other words injector duration is increased(like a choke on a carburettor ) but reversed. Carbs resrict air to richen mixture for cold start, fuel injected vehicles increase injector duration to richen , so smoother cold running achieved. The lambda sensor measures the oxygen content on combusted gasses and adjusts the injector duration, with the help of speed, throttle position and rpm sensors.

Basically , get off cold start(check idle speed is easiest indicator), before switching to gas. It should be better in the long run, as gas increases combustion temperature.

If the plugs are fouling,change the heat range of the spark plug so the plug doesn't foul at idle. Its worth checking them anyway as lpg dramitically shortens thier life.

Hope thgis helps!

Cheers,

Nick......

[Svee]

ok, ill give it a try. Thanks very much for taking the time to reply.

[cal]

Hello Alan,

I currently run my Avensis 2.0 on LPG but used to run my Caldina on LPG also which had the same engine as your 1.8 SE. Both of my car ran absolutely fine on LPG.

Now, when you say 'packed up' could you tell me more specifically what happened. i.e. blew back, when you come to a standstill it stalled, whether the engine hot/cold etc.

Also, have you had your spark plugs replaced recently? Does it run perfectly on petrol or is it lumpy?

cheers ;)

[Svee]

Hello Alan,

I currently run my Avensis 2.0 on LPG but used to run my Caldina on LPG also which had the same engine as your 1.8 SE.  Both of my car ran absolutely fine on LPG.

Now, when you say 'packed up' could you tell me more specifically what happened.  i.e. blew back, when you come to a standstill it stalled, whether the engine hot/cold etc.

Also, have you had your spark plugs replaced recently?  Does it run perfectly on petrol or is it lumpy?

cheers ;)

←

Hiya,

Whenever i got it back from Toyota they would test it there in the car park before i drove it off to show me everything was fine, which it was. I would be able to drive a few miles (its roughly 14 miles between my flat and Toyota) fine with no probs but the next time i go to start the engine it would start fine and dandy on petrol, i would wait the 30 odd seconds i was told to before switching to gas. switch it over (get the flashing green light on the gas switch) bring the revs up to 2 and a half to 3 and leave it there for a few seconds then as i back off the accelerator i get the click i should get (apparently) to say the gas system has kicked in, the green light goes steady instead of flashing (which it should do apparently) and then the engine stalls completely (where as before it would tick over nicely at this point on gas).

Its really weird. i have looked everywhere for a manual or some kind of opperating instructions for my gas system but it doesnt seem to exist. It took Toyota 2 months to even find someone who knew anything about my system :ffs:

Luckily my car runs fine on petrol so i am not stuck with a car i cant use. its just much more of a strain on my bank balance to run

I dont think i have had my spark plugs replaced at all to be honest

I have spoken to the LPG guy they keep sending my car to and he said he has had my car rigged up to some diagnostic equipment and all he could find wrong last time was a very slight leak from the gizmo that mixes the gas and air which he kindly fixed.

I dont know if its anything related but my car does have a loud squeeling noise coming from the engine. It seem to be happening whenever you would expect the fuel pump to be working (its quiet to non existant at idol but when driving its much louder and goes louder/quieter with the load on the engine) but it seems to go away once the engine is hot.

Thanks

Alan.

[cal]

Hello Alan,

Thanks for your reply.

As you may know, LPG is difficult to combust compared to petrol thus ignition system must be perfect otherwise it will throw all sorts of problems. Hence I asked you about the spark plugs as with petrol, you may not notice so much but the moment you flicked to LPG, it may show symptoms. For your information, 7A-FE being a leanburn engine by birth, it specifies platinum plugs but this does not go well with LPG. Thus I have tried and tested various plugs and found the NGK plugs best. I would recommend NGK BCPR7ET. It is not a platinum one but goes well with LPG. Unless you are 100% certain that the plugs are OK, I will start by replacing the plugs.

It sounds like a weak mixture. You see, the weather becoming hot at the moment mean less oxigen in the air thus the mixture can get leaner. More so, if the initial set up was lean to start with which can cause the car to cut out. Usually there is a black plastic screw/nob kind of thing on top of the vapouriser in the engine room. If you turn this screw anti-clock wise which will rich the mixture. If you turn too much then the mixture will get too rich thus try turning less than 1/4 turn and see what happens. This is best performed with the system hooked up to a computer so you can monitor the mixture as you do but, I don't have one myself so I tend to use my nose. Smelling the exhaust fumes to determine the richness. This is harmful if you do it too long so no more than 10 seconds at a time.

About the sqeeling noise, this worries me. If it is slipping of the belt, it won't matter so much but it is due to air sucking through the inlet manifold, or other areas this can again alter the mixture which could cause the symptom that you are experiencing.

Hope it gets sorted soon. LPG is great!

[Beardie]

Disagree about the plat plugs...I've done 150,000 on them and they are no problems on LPG. I would suggest leads and set up if there are plug problems. The stalling will most probably be caused by a lack of fuel (starvation). Therefore start by checking that there is a good supply...ie that there is no dirt or any other matter in your tank. The pick up pipe does have a mesh cover to stop dirt passing through the 6mm pipe, but any dirt being sucked up will block the pipe. Obviously once the engine is shut or switch to petrol, the pressure in the line will fall and the dirt released thus allowing the lpg to again enter the pipe. It could be that there is sufficient lpg in the lines to allow for a few miles of travel before you suffer fuel starvation again.....let me know how you get on...

[ronnyboy696]

i would never get a lpg conversion personally. they ruin the engines. burn out the valves.

[tubaman]

I ran a Rover 623 (Honda DOHC engine) on LPG for four years. Only ever had minor problems with the LPG system AND it was an early system that sucked the LPG in via a venturi (not injection and more like an old carburetor system !). It still worked great.

But, engine failed twice ( 2 x cracked cylinder heads - aluminium) - don't know if it was anything to do with running on LPG.

Any ideas ? What do you think ? My hunch is that LPG contributed to the cracked heads but not sure how.

[ndsblack]

I ran a Rover 623 (Honda DOHC engine) on LPG for four years. Only ever had minor problems with the LPG system AND it was an early system that sucked the LPG in via a venturi (not injection and more like an old carburetor system !). It still worked great.

But, engine failed twice ( 2 x cracked cylinder heads - aluminium) - don't know if it was anything to do with running on LPG.

Any ideas ? What do you think ? My hunch is that LPG contributed to the cracked heads but not sure how.

←

The reason that the heads cracked on your rover is that the engine may have been a 'K' series engine. Commonly known as the 'boil in the bag engine'!!

Enough Said!!

[cal]

Hi Beardie,

Is your system single point or injection type? Mine is a single point and when I used the platinum plugs, it caused blow-back a lot. So I now use conventional ones.

------

ronnyboy696,

Some engines are not suited to run on LPG. Certain engines such as Honda, Citroen and Ford (earlier Zetec) engines are one of them and suffer from symptoms that you have described. However, Toyota A series engines are fine running on LPG as both Beardie and I have proved it.

------

tubaman,

Crack on the head is often caused by excessive heat or temperature difference between the intake. Now, running on LPG does makes it run a little hotter inside the combustion chamber than running on petrol and if the cooling system is either not running right, i.e. blocked coolant passage or knackered water pump, it could cause the head to crack. Also, if the LPG mixture is not set up right, it can cause this too.

Now, for my heat solution, I use synthetic oil and use a cooler spark plugs. On the A series Toyota engines, the specified heat value for the spark plugs on NGK scale is No.6 but I use a step cooler one which is No.7 such as BCPR7ET ( the '7' bit is the heat scale used).

I don't know what caused your Rover's head to crack but it could be the weaker head design which would be this will be one of the engines that are not suited to run for LPG.

[tubaman]

Just for the record, the 2.3 DOHC engine in my Rover 623 was a HONDA unit and not the infamous K Series from Rover, but, thanks for the excellent info on this thread.

[Beardie]

Cal,

The Avensis and carina E (4A & 7A) are not single point but classed as multi point injection.This is different to sequential by the way. They will be fitted with a 1st generation system in most cases which uses a mixer in the air intake. You could have an injection lpg system but I'd be very surprised. The blow back is purely to do with very lean mxture and incorrect timing. These engines can have the timing advanced to provide much better drivability and increased bhp, whilst still retaining excellent fuel consumption. Ronnyboy thinks they burn out valves, maybe so if it's been set up by a novice, but I have my earlier engine stripped (which had no problems) an have the head to prove the valves look like a 10,000 mile engine. It had done 200,000 miles!. Anyone is more than welcome to come and look. The only reason i changed the engine was that I got a brand new Avensis unit for a few hundred quid! on e-bay....The 4A and 7A units are solid for LPG. Some other manufacturers do not build the valves for alternate fuels and maybe ronnyboy has this in mind...don't disagree if this is what he thought. The later vvti Avensis units are a point in case, the valves benefit from the occasional blast with flashlube to stop burn out. If u want LPG, do some homework and ask around. I'm embarking on getting my Audi A6 done shortly so I'll provide feedback should the need arise...

[Beardie]

Cal

forgot to add the 2.0 3S units as used in the Carina, Avensis, MR2 and early Celica's are bullet proof as well. IMHO they are a beautiful design of an engine that will go on and on forever. Don't be tempted by the vvti as a replacement! it's not a patch on the old kit!

[cal]

Beardie,

Thanks for your reply. Sorry I didn't make it quite clear. I meant whether your LPG system was a single point (mixer type) or injection type (SGI).

Let me know how you get on with your A6. I don't know what age your A6 is but if you have the later model with plastic inlet manifold you might be wise going for the SGI.

I agree about the rock solid 3S units. Mine has just gone around 136,000 miles and still going strong. OK it is ancient (first appeared 1986) but tough.

[Beardie]

All my Toyota's have been single mixer, 1s gen kit, simple and easy to fix. I have always used AEB leonardo on these and have no real issues. The A6 will be getting the full sequential injection (alloy manifold - 2000 - 1.8 Turbo). Booked in this weekend. The carina e has been my favourite as it has the lean burn unit and still delivers exceptional mpg, more so than my Corolla with the non lean burn.

[Radiodanno]

All my Toyota's have been single mixer, 1s gen kit, simple and easy to fix. I have always used AEB leonardo on these and have no real issues. The A6 will be getting the full sequential injection (alloy manifold - 2000 - 1.8 Turbo). Booked in this weekend. The carina e has been my favourite as it has the lean burn unit and still delivers exceptional mpg, more so than my Corolla with the non lean burn.

←

I have the 3sFE engine. a few people have said my car isnt suitable for conversion to LPG, toyota couldnt tell me (!Removed! dealers! :ffs: )

So can it be done. AND are there any grants still going around to help fund the conversion? i know there were a while back

Danno

B)

[sjrainsford]

Yeah, my Rav4 runs the 3S-FE unit too. I'm considering it.

Actually I fancy doing it myself, am an engineer and have access to most kit I may need.

Then again...

[cal]

Hi Beardie,

Thanks for your reply. My system is also using Leonardo + Romano vapouriser with Pitagola emulator and works great. So did my previous 7A-FE.

As for your A6, if it is a Turbo then SGI is way to go. Let me know how you get on.

-------

Radiodanno, sjrainsford

3S-FE is brilliant with LPG. I have been using LPG on my 3S-FE Avensis for a year now and covered just over 40,000 miles still going strong.

People say all sorts of things. Even when I converted my previous car, people said either not suitable or valve problem candidate. I often confronted those morons and they usually unable to tell you which type vehicle or engine type which is likely to cause the problem they have described. Anyway, I drew my own conclusion and went ahead with the conversion and glad that I did. It appears that Vauxhalls, Volvo, Fords and Land Rovers are commonly converted to LPG but not so mush so on Toyotas thus people don't seem to know much about and make worrying comments.

As for the grants, one time Avensis 1.8 7A-FE variant was listed but quickly withdrawn. Only Toyota that is applicable for the grant status is Prius. The grant for the Prius is for purchasing it, not for LPG conversion but if you managed to convert a Prius to run on LPG, that'll be an ultimate cheap to run vehicle of all!!

I was fantasising how cool it will be to convert Lexus RX400h, the new hybrid SUV. Power and comfort of a luxury car and running cost of a diesel Yaris!!

[Beardie]

I back Cal...3S-FE not problems...sweet runners and longevity to boot. Just make sure you install a closed loop system for hassle free motoring. The annual drain of the vaporiser helps remove the tar build up and keep the response nice. Only reason i've got an Audi is to transport my old dear around the country. The toyota's are not the best as regards comfort on very very long trips...My carina E is still on the drive waiting for the next 100,000 miles !...ps anyone else thinking about LPG with the 4A, 7A and 3S...don't hang about...there are fewer and fewer with low miles knocking around.

[Beardie]

Cal

A6 now back from the garage....YeeHaaa...it's superb, fitted with a SGi kit. Can't tell the difference in performance. Mines a 1.8T (150bhp) on a 2000 plate. Recommended.....I used Panache AutoGas in Manchester just for the record...worth the trip from Shropshire!...

[sjrainsford]

Hi Beardie. How much are we talking for a conversion these days?

I may possibly use those blokes in manchester myself, would always act on recommendation.

[Beardie]

SJRainsford

I think there is some variation depending on vehicle, but I reckon it's the best £1600 I've spent. Speak to a chap called Sam at Panache AutoGAs See ://www.panacheautogas.co.uk/.

My first Carina was done in 1999 for £750 and never looked back.