LPG ECU piggy-backing causing main ECU failure? V6

[westonwarrior]

realy strange this

I read a reply from LPG imports earlier so I know one was here and the history says that 2 posts should be here from them but they are not showing.
As I type the last poster shows as lpgimports but the post has vanished.
Its not been removed by the poster or any mod.

wow I found how to fix it

[mikeWalsall]

Strange ...

I read Paul 'lpgimports very informative post earlier ... a little later I went back for another read to absorb the info .. and there it was ..gone ..!!

Just had another look at the topic and there it was ..there ..!!

[Ron Miel]

If anyone ever wants me paul at lpgimports.co.uk or a PM which triggers a email anyhow. Sometimes am really busy and when I get home computering is last thing to do, other times I am online till early hours.

Paul

Hi Paul. Thanks for all the info above. Yes, temporary fix only at present, as far as I'm concerned, although still going strong up until now. That sounds a good place for the LPG ECU, and you obviously agree that accessibility is a prime consideration. When time and weather permit, I'm going to pull the old Bongo to bits somewhat, to get at that loom, and may be able to reposition the LPG ECU as you suggest, while I'm at it. As I already said (and as I'm now more than a bit suspicious about the original installation quality, anyway), I'm definitely going to take a close look at all that loom soldering work - and yes, intend to attack the ECU to loom connections with switch cleaner. As an RAF-trained former aircraft radio fitter, I fancy I know a bit about soldering, and keeping connections good - if we didn't solder well, or ensure connection integrity, the consequences could quickly be pretty dire

To use the two spare injector driver ouputs in an LPG ECU, do you have to re-programme it, or can you identify loom inputs and outputs easily, and just transpose the connections? That could be very useful, if an LPG ECU driver circuit goes down - have you known that to happen?

Am writing to ask Ian to update the LPG Fact Sheet, from talking about ECUs working in parallel to ones working in series, which might help to reduce the number of petrol running faults that peeps report with LPG conversions. It probably needs expressing in simpler terms than either of us has done so, so far though - working on it!

Didn't PM you, as I thought it should be something I could sort out with a bit more application but I would have called in to see you, passing by some time, if I hadn't managed to. PM and subscribed-topic email alerts are not working at the moment, due apparently to a server problem, and that was another reason I didn't. Reminds me that I need to add "PM sent" in a couple of threads, for that same reason - just realised why messages haven't been read

Cheers,

David

[Ron Miel]

........Just hpoe you solve this one David, so I can finally get mine converted on 73p a litre.

PM Sent, Mary. Just realised you've not read it, due to alert emails not going out at present, apparently result of a server problem. Cheers, David

[lpgimports]

LPG ECU's are fairly resilient, water ingress or getting spiked can kill them though, like any electronics things do go wrong now and again, if one of the not used sets of gas injector wires needed to be used it would be a case of wiring it in and using the corresponding taped up plug to fire the gas injector for that cylinder, if you knew what you were doing fairly simple but if your not familiar best left to someone who knows about LPG.

Pre made looms do exist and are great to use on popular cars using modern plugs, and where or course access permits, for instance say a 2005 focus, use a pre made loom unplug the petrol injector plug then plug in a male plug into it and then corresponding female on the gas loom back onto the injector ten seconds an injector job done... go to 15 year old Japanese vehicles and plugs are different wiring connections can be inverted and it is physically impossible to fit some of these looms in or they are just not made in the plug types required. So cut looms have to be used, like anything soldered, joints need to be good, I prefer to cut into the loom, about half way between chassis and engine and then stagger joints so they are all in different places, in most cases special tinned hollow tubes are crimped around the wires being joined then soldered then heatshrunk with glue filled heatshrink then wires laid back into loom, taped in place then the cut tube loom protection put back over the whole lot and then this taped firmly back into place. I have seen other installs where all connections are made at the end of the protection where the loom splits up on the chassis with all the connections visible and purely taped.

Paul

[mikeWalsall]

Reading posts like this .. I am glad Paul as got my Mazda in Coventry doing the LPG conversion .. and I have his (unused) Ford Freda on my drive ..!!

[Ron Miel]

..........I just found this http://autogashelp.co.uk/InjectionSystems2.aspx, which suggests to me that, if he's got it right*, the fault is probably either in the LPG ECU, or the wiring from it to that particular petrol injector.
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*(The only bit I perhaps question is this: "A greatly reduced signal is sent to the petrol injector which is not strong enough to open the injector, but is enough for the petrol ECU to not see a fault." Doesn't he really mean not long enough, in duration, to open the petrol injector, rather than not strong enough? After all, the main ECU just provides a negative to an already live solenoid, so unless resistance is added, the applied voltage isn't altered - or is that what it does do?)

Subsequently realised that the bit about still sending "reduced" signals to the petrol injectors while running on LPG must refer to more sophisticated engine management systems than in the Bongo - ones with dedicated injector pulse sensors feeding signals back to the main ECU. Paul/lpgimports subsequently confirmed that by PM, and says that LPG systems for that type of installation also have to be capable of emulating the missing petrol injector sensor signals, to spoof the main ECU into not setting off an engine check light.

There's another current forum topic, which might be pointing towards a similar LPG system connector problem, at http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=53033 - and I increasingly think there have been a number reported here in the past, which may or may not have eventually been sorted. Certainly, there seem to have been a fair number of LPG conversions, mine included, reporting persistent, or intermittently recurring, rough running of unknown cause - and much money has been spent on ignition systems, fuel systems, etc., not always successfully.