injector fails

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crankedside
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injector fails

#1 Post by crankedside » Wed Jan 16, 2019 3:24 pm

Hello all!

First of all, i'm new here ;) I'm from Belgium driving a 2nd gen dodge ram 5.2l v8 ! Which is running an OMVL dream XXI installation of lpg. Been driving this truck for 4 years now.

Recently i started having problems on lpg , unstable rpm & no driving well. Managed to figure out if i tick 1 of the injectors , the car picks up a stable rpm & drives well.
Now the injectors installed , been replaced once few years ago. They can't be ordered anymore , and no shop has them. Only the newer generations, with the blue housings are available. Mine is still the old type, black housing. I'm wondering if i'd order some of these newer types, will they communicate with my lpg computer?
And will they run smooth on them?

I believe this is the right forum to ask it on :p

Thanks in advance ;)

Brian_H
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Re: injector fails

#2 Post by Brian_H » Wed Jan 16, 2019 11:24 pm

What I'd suggest you do first, is to swap the electrical connection and gas pipe from your dodgy one to one that works currently, and make sure the fault follows the injector just to rule out a problem that swapping injectors won't fix. Just in case its something else causing the problem (kinked hose, dripping petrol injector, electrical issue etc). Also if its the type of engine with individual coil packs for each cylinder, this would be worth ruling out before you go down the route of injectors, as a fault on the ignition can be more noticeable on LPG than petrol as well, again you may be able to swap bits around there to check it doesn't follow the coil pack etc if it does stay on that cylinder with a different gas injector.

You should be able to put a different injector on there, but it will depend on what the ecu can support, this can sometimes be down to what firmware is loaded on the ecu as well, so it may help to list that if you can. If you intend swapping them yourself you will need to recalibrate it, but I'd guess you have a lead already if you can switch off the injectors so that shouldn't be a problem.

Hopefully Simon or someone else here can advise what they would suggest as being your best bet injector wise both for ecu and vehicle. There may be newer options that are compatible with the available ones in your ecu without explicitly being listed.

LPGC
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Re: injector fails

#3 Post by LPGC » Thu Jan 17, 2019 9:43 am

Do you mean tick one specific injector (switching that cylinder back to petrol) causes the fault to go away or ticking any injector causes the fault to go away? This is important because In the case of any the fault probably wouldn't be injector related at all, in which case it would more likely be because a fuel return system isn't working. This is unlikely because wouldn't expect a 2nd gen Ram to need a fuel return.

All good advice from Bri.

Early OMVL rails had an aluminium body, the later OMVL rails (Superlights) have a plastic body. Aluminium rails could be made to flow more gas than Superlights because they'll take a wider nozzle but Superlights flow well if the little (grub screw like) nozzles are totally removed. Later black coils on aluminium rails could be 'Fast' (3ohm) or the 'pre Fast' coils (higher resistance), blue coils on aluminium or plastic rails are 3ohm. Even if your old coils are pre-fast the software should allow you to select fast injectors so you can switch injector types to Superlights with your ECU. As usual after swapping injectors you'll need to re-calibrate anyway, so if you have to change injector type to Fast it won't be a disadvantage. It is unlikely you have pre-fast coils on your injectors because your ECU supports switching cylinders back to petrol, this ECU feature was not available before Fast injectors, and also any ECU firmware that supports switching cylinders back to petrol (while running some cylinders on LPG) supports Fast injectors. Injectors don't really communicate with the ECU, their electrical components comprise just simple electrical coils which the ECU feeds with power to create the magnetic field which pulls the injector plunger open. One of the aluminium rails will have a temperature sensor, Superlights are available with or without a temp sensor, if you switch to Superlights at least one of the Superlight rails you order will need to have a temperature sensor. Aluminium and Superlight temp sensors are electrically compatible but physically different, a temp sensor from an aluminium rail won't fit on a Superlight rail. The two types of rail are similar in dimensions and are mounted on the same rubber legs but spacing between legs is a bit different.

You may be able to buy rebuild kits for the aluminium rails... in fact the posts etc are not much different between aluminium and Superlight injectors. Dai @ Classicswede will have more insight on this.

Simon
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crankedside
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Re: injector fails

#4 Post by crankedside » Thu Jan 17, 2019 12:28 pm

Thanks for the help so far!

I've been looking at the connections , electrical & the hose. Doesn't seem different then others, no bends or rips etc.
All my electrical wirings have been replaced last year or 2 year. Anyway i'll look into swapping it for testing.

So when i hit the Injector that fails, it starts working again.
Like it's stuck & the hit breaks it free..

When Simon talks about ECU , we are talking about the LPG controller/computer unit? Or the car it's "PCM" ? I will see if i can get to know what firmware ver. Is on it :)

I will be installing the rails myself , also connection. And take it to the shop to test for leaks & recalibration.
I'll look to post more details on my current injectors , what type etc also ;)

Thanks in advance !

Brian_H
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Re: injector fails

#5 Post by Brian_H » Thu Jan 17, 2019 7:08 pm

Ah, I thought you meant switching it off, not giving it a whack!. That sounds like its sticking I'd think it was worth a try with some injector cleaner first (at least good enough chance I'd give it a try first). Rebuilding it probably better, but if you can't get the bits may not be an option. This stuff has been recommended by others in the past > https://www.lpgshop.co.uk/ic12-injector ... ant-100ml/ you can find 50ml bottles of it as well, you might find those easier from somewhere your side of the channel anyway.

Yes, the ECU Simon's referred to is the lpg one/the OMVL one rather than the one fitted to the car (PCM).

There will be a single plug that should have a cap on the end of it on the lpg loom thats currently not plugged into anything - this will connect a lead to then connect to a laptop, you'd need that lead, the appropiate software and a laptop, Given your in Belguim you may be better looking locally, but an example is here > https://tinleytech.co.uk/shop/lpg-parts ... g-systems/ - the same website has downloads for the software as well. That software will tell you the firmware level, but from what Simon's said above you probably don't need to change that at this point.

I've got the blue injectors https://tinleytech.co.uk/shop/lpg-parts ... sl-904502/ on my 4.0 V8 Disco with the nozzles removed as described above by Simon and they work fine on that, also worth knowing that the coils on those ones are easy to remove and swap if required (not sure if thats the case with your other ones). I've also got the same injectors with the nozzles on a Focus and they have been fine on that as well so seem a good option to pick.

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