fuel indicator

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taximan1256
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fuel indicator

#1 Post by taximan1256 » Thu Oct 03, 2019 12:29 pm

my fuel indicator for my omvl dream xxi g on a Mercedes ml350 does not light up when I turn my ignition on. I have checked the only fuse I can find on the loom and replaced as a matter of course but no joy new switch fitted still the same, continuity on small four pin plug is showing ok. I am at a loss this happened after lights went nuts flashing beeping ect not been able to use gas since,rebuilt the vaporiser with new seals o rings ect still no joy has anyone got a wiring diagram out there please. have checked also all the solenoids all clicking when current introduced to them. no ideas left to try. Thank in advance.

LPGC
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Re: fuel indicator

#2 Post by LPGC » Thu Oct 03, 2019 2:19 pm

In addition to the main power connection (with the fuse) the OMVL loom has a red (or red with white stripe, or purple with white stripe) wire that connects to somewhere that only becomes live when the ignition is on, usually this is connected to the positive of a petrol injector. This wire is in the same sub-loom as wiring that runs to one bank (engine side) of petrol injectors. If this wire isn't connected the OMVL ECU will never turn on.

Your install may have 2 black plugs between the main OMVL ECU loom and the petrol injector wiring (one plug for each bank of engine cylinders) but only one of the plugs on the OMVL ECU side carries the red wire to the OMVL ECU. If you do have 2 black plug connections and they have been swapped around it is likely that the red wire isn't connected to positive when the ignition is switched because it is likely that the installer only connected the red to petrol injectors on one cylinder bank (what the OMVL ECU should see as bank A). If you have 2 black plugs try swapping them around.

Don't forget that besides the fuse and main positive connection to the ECU it also needs a good earth.

if you've got a good earth, good main live and power to the ignition on wire the ECU should turn on at least for a few seconds (until it turns off again if there is no rpm signal). If it doesn't it suggests a broken ECU or bad connection between the ECU and it's loom (check ECU pins and the loom that connect directly to the ECU are not corroded).

It is futile to rebuild / replace other components because the ECU only needs the earth, main power feed, 12v to the red wire and of course connection to the switch to turn on and light the switch up.

Simon
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Brian_H
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Re: fuel indicator

#3 Post by Brian_H » Thu Oct 03, 2019 6:36 pm

You should be able to find the wiring diagram included with most of the software - there is a large selection of the software at https://projekt-tech.com/diagnostic-programs-pm-23.html

Can't see your specific version there, but Simon has given you details above of what should be connected, the usual points of failure are either the battery connections, or the inline fuse holder itself, though any break in the wiring of those connections will cause it to become dead until you fix it.

taximan1256
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Re: fuel indicator

#4 Post by taximan1256 » Tue Oct 08, 2019 12:12 pm

Thanks Guys checked all the wiring still dead power going into ecu nothing coming out. going to have to find someone in Sheffield to bench test ecu if that is possible just to make sure its not fried.

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Re: fuel indicator

#5 Post by LPGC » Tue Oct 08, 2019 3:59 pm

I'm by far your best bet for telling you if the ECU is fried or not and doing any other diagnostics. And I'm not far from Sheffield in South Elmsall.

Another thing just occurred to me - You've said it's a Dream XXI G... The G tells us the design of the reducer but not the ECU. There are 2 main types of Dream ECU you could have on your car... one type is AEB2568 the other type is Piro. The AEB2568 and Piro use a different switch and won't work with the wrong switch though the switches look very similar and use the same plug. In fact just because you have a Dream G reducer doesn't necessarily mean it will have an OMVL ECU.
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
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07816237240

taximan1256
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Re: fuel indicator

#6 Post by taximan1256 » Wed Oct 16, 2019 5:02 pm

Hi LPGC
Got the gas ECU off the car now on the front it is a OMVL Dream XXI Injection system by Westport 5,6,8 cylinder, On the rear Cod. AEB 2568D 1015215700203 N.L 10/15/2, 03/03/15, MADE IN ITALY, AEB. S.p.A TIPO ICU. Did a few more checks still no power to switch when ignition is switched on all circuits showing continuity searched for a second fuse but with no luck I'm assuming that power has been taken from a switched live but can't find it, So it looks like a trip to South Empsall with Ecu in my hand to make sure its not fried somehow All the wiring shows continuity but still no power to switch.

Brian_H
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Re: fuel indicator

#7 Post by Brian_H » Wed Oct 16, 2019 9:39 pm

The most likely place for a switched live to have been taken is from the petrol injector feed at the manifold, sine you have to take the injector pickup wires there anyway. Have you found where the injector breaks have been done? Typically that will be very close to the injectors as it's the easiest place to get to

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Re: fuel indicator

#8 Post by LPGC » Thu Oct 17, 2019 3:51 pm

You've confirmed it is an OMVL Dream N ECU as opposed to OMVL Piro ECU or any other ECU. So if your system has the square (not oblong) switch it should use this switch https://tinleytech.co.uk/shop/lpg-parts ... er-switch/ and not this switch https://tinleytech.co.uk/shop/lpg-parts ... ro-switch/ Unlikely you have the wrong switch but note how they look very similar and they're not interchangeable.

The switched live is in the petrol injector loom to bank 1 (explained more in post #2), if there's 12v on that wire, 12v to the main power feed, earth to earth and the switch is connected the switch should light for a short time regardless of any other connections.

I can look at it but we'd have to arrange a date and time, I have got a lot of work lined up but we could sort something out. Worth checking the switch and the 3 main wiring connections first though.
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
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07816237240

taximan1256
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Re: fuel indicator

#9 Post by taximan1256 » Sat Oct 19, 2019 10:52 am

Will have a look for what you have described and give you an update. Thanks once again for your help.

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