My LPG install thread ;)

[gareth]

fantastic, cheers brian
i'll give that a go tomorrow

[gareth]

i managed to get my first backfire earlier... they go with a pop don't they!!!!!
i was driving along gently on gas, all warmed up and running well then BANG and the engine dies. it had split the rubber 'band' on the blowback valve and popped it off. 2 mins and some more PVC tape (i say more as it was already split if i'm honest !!!) and all was well again. the valve did the trick though as the AFM is fine.

oh, for everyones reference, i have some economy figures:
on a run to germany at 80ish most of the way, i got 32mpg on gas
round town, all short runs, starting from cold on gas (as above, cheers brian) tank one 13mpg, tank 2 17 mpg, tank 3 14.5 mpg. not bad really as i used to be under 20mpg on petrol on the same round town driving with my engine. the same weeky run on my rover 214 or 414 used to be about 25mpg so i'm still saving as the LPG is half the price.

i am a happy bunny

[daimlerman]

This is all very tempting, but I do like the reassurance of a spare wheel...

Carry one of those aerosol inflator thingys that you would put in the boot of the little lady's car to save her the hassle of changing a wheel.Will not work with a torn tyre,but will cope with a normal puncture.

[Brianmoooore]

I carry both a space saver and a couple of aerosols. Never used either in the 100,000 miles or so I've run on LPG.

[gareth]

I've been getting a few blowbacks recently. so far, about 4 of them. I've not messed with anything on the car at all since it was running fine. in fact, it still runs 100% sweeeeet on gas.

it's annoying because every time it goes pop, it splits the PVC tape that is holding the rubber band together on the blowback/clatflap valve

any ideas as to the reason behind this? obviously i should sort the valve out as they're really cheap but i keep forgetting and having more important things to fix! when strapped up again, it doesn't leak at all.

[Brianmoooore]

Got all the Leonardo stuff up and running yet? Under what circumstances do the blowbacks occur? Usual cause of blowbacks is a weak mixture.

[gareth]

err, no
things have been a bit hectic and i've just been driving it.

Lean mixture... that gets me thinking. i know i have a weak inlet manifold gasket on number 2, it's been waiting for the manifold to come off for a while and was bodged with RTV as a temporary fix. maybe the first blowback blew the RTV out and now i have a vacuum leak. i'll check that tomorrow.

two blowbacks have been on the overrun, downhill. one on start-up from warm (direct start on gas) and one when i hit the throttle after slowing for a junction.

[gareth]

forgot to update this... whoops!
i had a poke round and noticed the obvious fault...! one of the blowbacks had obvioulsy got past the blowback arrestor and popped the air filter box apart at the clamp and even though the filter was new, running without it must have made it run a bit leaner. i've put it back together, it's been fine for a week or so.

[Jon_Bmw]

I am getting rather interested in LPG. The possibility of a 65 mile commute is likely later on this year.

This is fairly local and finishing soon, I am pretty sure the tank is the only useable thing? Or would I be able to use a lenardo ECU with the rest of it?

[Brianmoooore]

This is fairly local and finishing soon, I am pretty sure the tank is the only useable thing? Or would I be able to use a lenardo ECU with the rest of it?

Missing ebay link??
Leonardo ECU, switch and stepper valve are ideal for use with an E30.
Since I can't see the link, I can't give exact advice, but the filter/solenoid and vapouriser should be usable as well.

[Jon_Bmw]

http://cgi.ebay.co.uk/LPG-Conversion-ki ... .m14.l1318

What a clot

[Brianmoooore]

Well, did you get it? Are you xyred?
The tank, valves, valve chamber, filler and vapouriser should all be usable.

[Jon_Bmw]

No i am not. I didn't bid in the end as I decided without advice I didn't really know what I was getting myself in for. I can't believe I left out the link in my first post. I had to go out for the duration of time between my first and second post. I think I will do lots more research and bother the LPG expert when I am slightly more knowledgable. I did think that went for a good ish price though.

[Brianmoooore]

I did think that went for a good ish price though.

It did! It was in my watching list, and I might just have had a five second to go punt on it, if I was sure I wasn't bidding against another zoner!

[Jon_Bmw]

Shite, sorry

[Brianmoooore]

That was only a 60 litre tank though, that actually holds 48 litres of gas, and 2001 is the date of the revision of the relevant regulations that the tank was made to conform with, not the manufacturing date. The tank is newer than 2001, and will be stamped into the plate, although it's not given in the ad.

[Brianmoooore]

Shite, sorry

Don't worry about it - I wasn't that fussed, - I've nothing actually lined up for it, but Warminster's not too far off my intended route this weekend!

[gareth]

update time
since sorting out the popped-open airbox, i've had no more blowbacks. result!

the only other problems i've had have been a bad contact for the earth on the solenoid on the vaporiser and when cold, it won't start on gas. however, when cold it does splutter on petrol for a few seconds too. it then takes a mile or so before it will switch over. this is annoying as that's a third of my mileage. any pointers brian?

[Jon_Bmw]

Got the Leonardo hooked up to a laptop yet?

[gareth]

nope....

[gareth]

right, i've run into problems.

recently it's been getting harder to switch over to LPG but i blamed it on the weather. then once or twice though i managed to switch over, it ran like shite and very down on power. then it then it stopped switching over at all.

thinking it was wiring related i started by checking through all of the solenoids. all measured up ok, had good earths and were getting 12V when trying to start on LPG.

as a secondary check, i powered all of the solenoids directly off the battery. here i think i found the problem. without the engine running but with the solenoids powered, there is a gas leak within the vaporiser itself. i took off the hose from the vapouriser to the venturi and blocked that as some gas was getting out into the inlet but there was still quite a lot leaking from the rear casing of the vapouriser

also, in this state, it will not fire up on just gas.
no gas seems to be escaping into the coolant.

I'm guessing the old looking OMVL R90 vapouriser has given up or needs a rebuild. As i'm off to the ring on friday, i guess i'll just put this down to experience and spend the extra £40 in fuel getting there

bummer........

[stonesie]

Gareth, have you replaced that hose yet?

I ordered 2 meters of the stuff and it's looking like im going to use less than half a meter, PM if you want the remainder


Sorry to hear about the vaporisor mate.

[gareth]

Not yet... Been busy getting the car ring-worthy!
How much was it mate? If it's uber cheap, i'll probably get some in along with the other parts i need when i get back from the ring, other wise i'll take you up on it. cheers for the offer, got to be worht a beer at the very least hasn't it.

[stonesie]

Well the 16mm internal is £5.43 a meter including vat from tinleytech + £3.50 postage per order, for what i have left over i was thinking a fiver posted

[gareth]

sounds like a bargain to me ;)
PM me your details and how you want paying and i'll get some wonga over to you. ta!

[gareth]

update for those who are interested...
i've had little time for tinkering so have spent a while running on petrol but have now sorted the non-starting prroblem. it seems when i shut off the gas (or just stop the engine) the stepper motor closes the valve right up and it then sticks. the LPG forum i've found helped me find this and apparently it's fairly common with the AEB setup. the cure is to loosen the screws holding the motor to the valve body, give it a wiggle, refit. hey presto a working LPG setup. i just don't want to think how much money i've wasted on petrol finding the out, i've been to germany and the pod all on petrol and it hurts!

oh, stonesie, i've only just remembered about the hose! do you still need a rear demister switch? if so, i'll have a rummage...

[Brianmoooore]

it seems when i shut off the gas (or just stop the engine) the stepper motor closes the valve right up and it then sticks. the LPG forum i've found helped me find this and apparently it's fairly common with the AEB setup. the cure is to loosen the screws holding the motor to the valve body, give it a wiggle, refit. hey presto a working LPG setup.

This is the only fault I've ever had with mine - usualy after a good run after the car has been parked up for several hours. I could unstick the valve in seconds at the first lay by, but the permanent cure was to replace the stepper valve.

[stonesie]

Since this is here i may aswell ask..... how the hell do you get a smooth transition to gas, ive been playing with the gas pressure and switch-over time and going back to petrol it's vertually seamless, it now pulls all the way to 5.5k and has its 4K surge on gas but the only way to switch to gas is on over-run and it takes 2-3 seconds

[Brianmoooore]

The only time you should be switching to gas is on overun - switching on acceleration is asking for a major blowback!
Will never be as smooth as the change back to petrol, since the time it takes for the gas to reach the inlet valves varies with revs, but you should be able to get it almost seamless.
The 2 - 3 seconds is the delay set in the software - how long the petrol injectors keep running after the gas is turned on.

[Jon_Bmw]

The best thing about mine is the switchover, its actually almost undetectable! You can detect it more when I switch back to petrol for whatever reason. I'm still having a few issues with warm idle, if doing about 70/80, clutch in and hold it in it will stall about half the time. It doesn't like idling on gas once it has warmed up. It hunts around dropping to around 600rpm up to about 1000rpm when it over corrects to stop it stalling. I think it could be to do with the long and thin track to the IACV on an iS. Its positioned on the side on the inlet manifold and all of the hoses are prone to crack. So its a fairly long path for a gas to take compared to an m20 IACV.

I still haven't borrowed the lead off Alex yet, so I can't confirm its not learnt 'badly.'

[Jon_Bmw]

A second and a half is all the delay needed in mine, much more and I think in my little 1.8 it would be getting into flooding territory(2 fuels, 1 lot of air)

[Brianmoooore]

Sounds like your stepper motor is bouncing from one end of its idle range to the other while the car is idling.
You need to hook it up to the laptop, and adjust the gas flow on the vapouriser so that it just bounces off the lean end.

[Jon_Bmw]

Is that tightening up the boundary that the stepper moter operates on idle function? Sometimes its spot on, so it will idle. I think I just need to draw in the two boundarys till it runs spot on I guess. I guess it has this option as the Lambda sensor input is delayed(every 5 seconds?)

On the vapouriser there is a couple of adjustments I think? Is one the idle control then and the other the main diagham(spel?) for normal A to B running. I haven't touched them as it came off a 2.0 with similar power output. But as it was a 6 pot, its possibly running rich on idle.

[stonesie]

Mine was off a 2.0 Audi A6 so i thought it would be fine on a 2.0 M20, wrong, it would only rev cleanly upto about 4k then it bogged down so ive been carrying an allan key around and tweaking it.


I think the changeover is set to 2 seconds at the moment, will try reduceing it to 1 and might enable the start-on-gas thing too

[gareth]

i really need to get a laptop to see what's going on!!!!
as mine was fitted to a M30B35 in a E32, i've been lucky i guess and adjusted nothing at all, however things wear and no two engines are the same so some tinker time should help me no end.

on gas is has a fantastic lumpy V8-like idle... at 500RPM evidence of tinkering needed i think. i guess the ICV is trying to control the idle but it's running lean due to incorrrect LPG settings?