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[Tezray]

You might be right, i'm just concerned that my injectors are inferior and my economy/performance may suffer. It's worth replacing the seals though and going from there.

The other concern I have with them is that the nozzles have been drilled out to around 3.0 - 3.1 mm which from what i've read is far too big 

[Kevin Wood]

You might be right, i'm just concerned that my injectors are inferior and my economy/performance may suffer. It's worth replacing the seals though and going from there.

The other concern I have with them is that the nozzles have been drilled out to around 3.0 - 3.1 mm which from what i've read is far too big 

No, I'd say that's about right for the vapour pressure you're running, and that's about what we use with the Valtek injectors on a V6.

Kevin

[Shallow Al]

Mine started idling really rough about a week ago on LPG and was perfect on petrol. To cut a long story short, I eventually pulled the injectors apart and found one of the O rings had broken up and was floating about inside the injector body. The O ring looked to me to be a sort of bump stop and does not form the seal for the gas, I may be wrong! So I cleaned the others up and put them back together.
 The lumpy idle has improved dramatically, but I have a loud tick from the one that failed.
 OK for now and have ordered a new Valtek injector rail.
 Very similar to your problem it seems to me.

It certainly sounds like it, although further investigation has shown that my injectors may be "Apache"  :-? as seen here second one down;

http://keshzen.com/lpg_cng_injector.aspx

and here;

http://www.ec21.com/product-details/LPG-CNG-Rail-Injector--3432962.html

I've been trying to find replacement Nitrile o-ring seals today but haven't had any luck so far. I think you're right about 1 of the o-rings acting as a bump stop, which is why mine are also quite loud as when the injector opens the 2 metal surfaces meet (as those o-rings have had it). There are then 2 more o-rings, 1 as the main seal and 1 as a backup, it's the main sealing o-rings that have crumbled.

Looking at the repair kits on ebay, the components look the same as mine so are mine Apache or Valtek? Maybe they're one and the same thing  :question

I have the same injector rail. Seems to be made in China but the internals seem the same as Valtek. On my Stag software, it is set to run as a Valtek 3 ohm set.
I have just got a new Valtek set of injectors for £38 delivered. Going to swap them when I get time and recalibrate. If the internals are the same, I will get some Valtek reconditioning kits off ebay and sort the old injectors as a spare. Most on this excellent site have no problems with Valtek injectors yet. They seem of good quality.
I had the same problems as you, rough idle on lpg and economy was down. I used to count on 300 miles to a tank, but now lucky to get 250 or worse. I hope the new injectors will sort this. Time will tell.
 

[Shallow Al]

Well, managed to swap out most of the injector assembly. Left the main body or manifold in situ as I did not want to have to drill the new nozzles, and the old ones would not fit in the new manifold.
What a difference all lumpyness at idle has gone and there is hardly any noise from the injectors themselves.
Did an auto-calibration and all was spot on, no map adjustment necessary. See how we go from here.
The old and new internals were identical, so I probably would have got away with a Valtek reconditioning kit

[Tezray]

Thanks for the update Shallow Al i'm glad it's given a big improvement. I'm heavily considering purchasing these;

http://autogas-lpg.co.uk/injector-sequential-injection/22-valtek-lpg-injector-rail-sequential-injection-3-cyl.html

For £65 I think it could be worth it for the economy/performance benefits from having new injectors...

[Lazydocker]

It can't do any harm, but those seem a bit pricey

I reckon you could get better/better value elsewhere  :-/

[Shallow Al]

Thanks for the update Shallow Al i'm glad it's given a big improvement. I'm heavily considering purchasing these;

http://autogas-lpg.co.uk/injector-sequential-injection/22-valtek-lpg-injector-rail-sequential-injection-3-cyl.html

For £65 I think it could be worth it for the economy/performance benefits from having new injectors...

Thats where i got mine. There was only one other set on ebay at the time for around the same price, and could not see much else on google. As said, to make life easy, and to prove a point to myself, I only changed the injector bodies and internals. For my problem it seems to have done the trick and I could well have got away with the Valtek kits that are cheaply available. The economy issue is yet to be proven one way or the other, but the car drives great for now. I will be putting the Valtek main body on and drill the nozzles later.
But of course you need six of everything.
The rubber end stop ring is a different colour to the old ones, so just may last longer.

[Tezray]

It can't do any harm, but those seem a bit pricey

I reckon you could get better/better value elsewhere  :-/

It's the cheapest i've seen, if you've seen them any cheaper feel free to let me know 

I refitted the injector rails and replaced the vapour filter and they are quieter and cylinder 6 is no longer 'missing' but I think i'm still going to replace the rails. I couldn't find any correctly sized o ring seals so I did a mega bodge involving the old worn seals and some ptfe tape  I also think i'm leaking gas slightly on the o/s bank so need to sort that.

SA - Good work with yours, sounds like a result 

[car-nut]

There is one other thing to consider. The solanoids on the LPG systems are prone to failing causing this issue. It might be a simple case of replacing the solanoids on the LPG system to make it work properly again as this can cause bad running eventually leading to lpg failure and with poor running on the car you are ricking the Lambda sensors and catalytic converter.

I had the same problem you are describing on my old 96 V8 Discovery with LPG and I spent months trying everything until at the end a friend of mine said, check the solanoids and it turned out 1 solanoid had failed. Immediately after replacing that solanoid my Disco was back to running perfectly on LPG.

And just to double check. If your LPG is manual switch over like my one was, do you allow your engine to warm up slightly first on petrol before switching over, as I made that mistake never having LPG before which is what caused my problems 

Hope this helps.

[Tezray]

Car-nut, my LPG should switch over automatically although it seems to be happy to switch over even when it's cold so I do switch over manually once she's warmed up a bit. I know this means my temp. sensor may well be on the pish but i've got bigger fish to fry at the moment!

I've splashed out on some new Valtek type 30's as shown below... mmmm, shiney 





I will be fitting these asap and seeing how she runs, i'm expecting big improvements. The settings on my ecu are already set as 'Valtek 3 ohm' injectors so I shouldn't have to change a thing, but I will recalibrate.

Fingers crossed  8-)

[Tezray]

Injector rails, filters and new lpg hosing now fitted;





Whilst I had it apart I found this pikey-style bodge on the temp. sensor  Someone has replaced the sensor in the past and they obviously couldn't be bothered to remove the old one so just cut the wires and bodged this one on and left it hanging in mid-air. It doesn't even look like the same sensor as the one screwed into the vapouriser 



So now I need to calibrate it all... as I don't have anyone that can sit in the passenger seat to watch the map whilst I drive the car, will I be able to fully calibrate it on my own? I've read the calibration guide written by Kevin in the maintenance guides, by the sounds of it I can collect the petrol map, then the lpg map and compare them afterwards? Do the maps need to be monitored whilst the car is being driven?

I've had it idling and revving on lpg whilst stationary and all seems happy so that's a good sign. There was a light smell of gas in the engine bay with my old injectors and hoses fitted, which to my relief has now disappeared  If I can get it driving as well on gas as it does on petrol i'll be a happy man.

[Shallow Al]

The maps will collect by themselves, you don't have to watch them. When it has enough points plotted, it handily draws a line of average value through them. Then switch to gas and do the same. Do an auto calibration before collecting the maps though, this should tune it roughly OK. Then it will prompt you to collect the maps.
Don't like the look of that temp sensor, I think that needs a fix.
What is it supposed to be sensing. Water or gas temperature?
 

[Tezray]

Cheers SA 

No it doesn't look great... I had a look on the lpg-autogas website that I got my injectors from and their coolant temp. sensors look the same as the one fitted. I'm fairly sure its the coolant temp. sensor, where is the one for the lpg? Is it just before the vapour filter?

I'll have a go at calibrating it today and report back later 

[TheBoy]

Tez - the filter is too close to EGR, you may need to do something about that


If yours is a Stag 300 plus, update to latest firmware,, which has a automatic calbration (in addition to the idle based one) called ISA2 - enable this, along with the beeps, to get a 'usable' calibration on it. Read the ISA2 part of the PDF to understand how to do it (the ecu asks toy to drive faster/slower in order to collect the maps, and then calibrates itself (not as well as manual calibration, but good enough )

[Shallow Al]

Looks like things have moved on since I last looked at the Stag site. Going to get some of that.
Thanks The Boy.
This forum always puts you straight, if you can say that these days.