Cannot switch to LPG

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Brian_H
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Location: Milton Keynes

Re: Cannot switch to LPG

#21 Post by Brian_H » Tue Mar 12, 2019 9:04 pm

It should hold it open, but if the solenoid isn't getting enough power to it, then you might find it fails to keep it open. Best bet with that is to feed 12v directly to both solenoids - if it drives as it should like that, then either you have a wiring fault, or the ecu is failing to provide enough power (Simon has said on a few occasions this can be worked around with using a seperate relay to control the solenoids, and using the ecu output to switch the relay).

It might be a useful diagnostic tool to put a 21w bulb in the place of the solenoid and see if it lights up properly or is dim, least then you know what you might be dealing with. Equally it wouldn't be a bad idea to check the battery pickup lead and fuse holder for corrosion or general grime, as I've found random problems can be down to a bad connection there. The fault you have is the same I had, I decided to swap the front end kit as it wasn't worth investing any further money into it at the time, as the car was reaching the end of its life at that point, and at least i could swap those bits to another vehicle then.

It won't work without the pressure sensor though.

evandavic
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Re: Cannot switch to LPG

#22 Post by evandavic » Thu Apr 11, 2019 8:35 am

Hi Brian,

I drove the car for about 300 miles two weeks ago (I don't drive that car every day) and most of the time, it was ok but switched back to petrol unexpectedly from time to time.
It's not very easy to gain access to that damned coil because it's located under the housing of the battery which is molded on the body. It'll try to remove it this weekend (if this is safe) to at least get the P/N and test it by putting 12V directly on the pins. Is it enough to but +/- from the battery leads on the coil pins?

Thanks for your help.

Brian_H
Intermediate Member
Posts: 1269
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#23 Post by Brian_H » Thu Apr 11, 2019 5:26 pm

It might still operate, but if its starting to fail the ecu might struggle to hold it open. By all means test it that way, but you'd be best to check its resistance as well with a multimeter at the same time just to rule it out.

If you can reach the top of it, there is a single bolt that holds it in place, it may help to loosen that slightly so you can turn the coil around the post to gain better access (what you describe sounds very much like the problem I found on the Mondeo I had fitted with one of those systems, you just couldn't get it off without removing the bolts that held the bracket onto the body first).

evandavic
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Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#24 Post by evandavic » Sat Apr 27, 2019 2:03 pm

Hi Brian,

I'll tackle this problem tomorrow, if the weather allows it. I was wondering if I can safely remove the solenoid, as if it appears to be faulty, I need to order a new one and need the P/N.
Also, I was wondering whether the LPG system includes a relay?

Thanks a lot.

Brian_H
Intermediate Member
Posts: 1269
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#25 Post by Brian_H » Sat Apr 27, 2019 8:31 pm

Mine had a bunch of relays on a board hidden in the drivers footwell, along with the rpm filter, and lpg ecu. Theres no guarantee where yours might be fitted, but tracing the wiring back may lead you to some relays.

You can remove the coil without a problem (the grey or black or blue plastic block). The post underneath can be removed as well, but be aware that this will vent whatever is in the pipework, As long as your rear solenoid is working that isn't too much to worry about, but do it outside away from any ignition sources or open drains etc. If you loosen it enough to let the pressure escape it should stop after a couple of minutes max (if it will run at all on gas, disconnect the back one and let it try to use up the pressure in the line first).

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