Battery drain - cause?

Pinger said:

Some work done today but no progress!
Opened up the FRC. Nothing obviously wrong with it. Someone has slaved from a relay earth tag and joined in 4 brown wires that then disappear into the loom. A bit further down the loom 4 black wires emerge and are connected to an eyelet that bolts to the body as an earth. Suspect this is all LPG stuff. Opened up the trunking on a huge chunk of harness and there's taped connectors all over the place. Next step is to check the colours of wires the LPG ECU connects with and try and identify what is what. Am I correct in thinking GM use black cabling for earths? Does anyone recognise the description of the 4 black wires earthed to the body as something they have on their truck? It bolts to the inner wing horizontally (bolt head pointing upward and slightly inclined towards the centre) and the bolt's head is 13mm across the flats. There's a shitload of wires coming out of the FRC - but they are all supposed to be fused?

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RawbDidIt said:

The wiring downstream of the fuse box shouldn't be an issue since they're all fused or hooked up to relays. You have already removed that from the diagnosis by removing the fuses and relays. The issue has to be somewhere between the connection to the main power and the feed side of one or more fuses/relays--you've isolated everything else. Somebody jump in here if I'm wrong, but in my mind the best way to fix this is to replace the fuse box based on the information you've provided, there's no other component or circuit to check. Good luck finding that part though, just gave it a once over and I think it's P/N 12146452 but, no pictures to confirm.

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Pinger said:

Alas - not so simple.
With the FRC feed wire disconnected at the FRC - no drain. Brush it against its terminal - light spark and the drain. Definitely downstream from the lead. The FRC itself is so simple there's not much can go wrong with it.

I need to better understand why someone has connected an earth to a relay earth tag withing the FRC. It's not an obvious thing to do!

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RawbDidIt said:

Right, but if it persists with nothing connecting a load to that ground, I fear you're wasting time diagnosing an issue which doesn't exist. I agree a fuse box isn't terribly complex, but by the diagnosis you've already done, the issue can only be between the feed side of the relays and fuses and the power line to the battery. If something is spliced I'm on the power side, that makes perfect sense, but spliced into the ground shouldn't make a difference in the world if the draw is present with no connectivity of any circuit to that ground.

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Erik the Awful said:

Unbolt the FRC from the chassis and see if it persists?

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Pinger said:

What I need to get to the bottom of (if only to eliminate it) is why there is additional wiring in the FRC. Why would anyone choose an earth terminal for a relay buried inside a fuse box when there are so many other easily accessed earths available? Does not make sense. That of course assumes it is seeking an earth.
Another possibility is that it is actually the earth path for the relay (and the rail it sits on). Which raises the question, 'what happened to the FRC's proper earth?'.
!

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beaugranbois said:

Have you considered pulling the LP conversion? I had one in my 95 and it was a lot easier to remove then I thought. Or was you planning on keeping it and using it? Speaking of, I have a full LP conversion if anybody is interested in it. I believe I cut the conversion out of the injectors, distributor, maf, o2 sensor and fuel pump. I completely cut mine out, saved all of the components and marked the wires in case some else wanted it. It took awhile and another issue kept me from getting mine going for awhile but I figured it out.

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