Samurai 1.6 fuel pump wiring

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Larry
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Samurai 1.6 fuel pump wiring

Post by Larry » Sat Nov 21, 2020 3:29 pm

Hi all,

I've had to fit an electric fuel pump as my 1.6 8v has no mechanical pump.

I've stolen an ignition live that I think was spare after removing the old aisin carb. Runs great as it is...

However, it's not ideal that the pump stays going in the event of a crash where the engine might cut out but the ignition could be left on.

Is there a simple way to get an live that is only live when the engine is running? From the coil or the oil pressure switch maybe?

What have others done?

Thanks 👍
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Larry
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Re: Samurai 1.6 fuel pump wiring

Post by Larry » Wed Nov 25, 2020 9:46 pm

So having done some more reading, I think taking a "T" off the 12v feed from the instrument cluster to the oil pressure switch might work. I'll use this to trigger a relay to power the fuel pump.

I'll then either
A) package a non return valve on the fuel line

B) add a push button primer
or

C) fit a timer relay to prime the pump thats triggered by ignition live. Similar to glow plugs on a diesel.

Any better ideas, please let me know! ;)

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Jordi
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Re: Samurai 1.6 fuel pump wiring

Post by Jordi » Thu Nov 26, 2020 6:45 am

If its a self priming pump shouldn’t need a priming switch.

When the engine turns over to start and the oil pressure builds the pump should kick in.
1988 Samurai - Truck Cab & Tray Back - 1.6 8v & HIF44 - Snorkel - Stack Exhaust - PAS, YJs & 33s - Trussed, Gusseted & Pumpkin Capped Axles - 4.3 R&Ps - 4.16 T/Box - Rear Air Locker - Full Float Back Axle & Discs - RCV Front Shafts - X-Eng Handbrake - Custom Fuel Tank

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Larry
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Re: Samurai 1.6 fuel pump wiring

Post by Larry » Fri Nov 27, 2020 5:10 pm

Thanks Jordi, that's a fair point, I'm not sure exactly hoe the pump works but judging by the in line filter between the pump and the carb it doesn't appear to drain back, so I should just try without first and see how I get on :thumbup:

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Re: Samurai 1.6 fuel pump wiring

Post by Anton » Sat Nov 28, 2020 4:36 pm

Thinking about it, your solution would have the added benefit of saving your engine if you crack your oil pan or kill your oil pump. It's a pretty good idea.
1985 SJ413VX (SJ50V) with SPOA, rear disc brakes, 31x10.5R15 Kaiman Malatesta tyres, an MOT and a lot left to do!

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Re: Samurai 1.6 fuel pump wiring

Post by Jordi » Sat Nov 28, 2020 6:20 pm

The instructions for most electric pumps have them wired via the oil pressure switch for safety.
1988 Samurai - Truck Cab & Tray Back - 1.6 8v & HIF44 - Snorkel - Stack Exhaust - PAS, YJs & 33s - Trussed, Gusseted & Pumpkin Capped Axles - 4.3 R&Ps - 4.16 T/Box - Rear Air Locker - Full Float Back Axle & Discs - RCV Front Shafts - X-Eng Handbrake - Custom Fuel Tank

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Re: Samurai 1.6 fuel pump wiring

Post by Larry » Sat Nov 28, 2020 10:43 pm

Anton, I thought so too! A nice safety net :thumbup:

Jordi, that's interesting, mine didn't come with instructions but it makes sense.

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Re: Samurai 1.6 fuel pump wiring

Post by Anton » Sun Nov 29, 2020 2:22 am

I don't remember my pump having instructions either. It was a facet pump, so maybe it did and I just did the typical bloke thing and ignored everything in the box but the pump...
1985 SJ413VX (SJ50V) with SPOA, rear disc brakes, 31x10.5R15 Kaiman Malatesta tyres, an MOT and a lot left to do!

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Re: Samurai 1.6 fuel pump wiring

Post by Larry » Wed Feb 10, 2021 2:41 pm

Just an update on this..

So I did try to wire it via the existing oil pressure sensor but it's only a single pin sensor. By the looks of it you need a 2 or 3 pin sensor so that one pin can illuminate the low pressure warning light when the ignition is on or when there is genuinely low pressure whilst running. And the other pin needs to power the fuel pump relay when there is oil pressure. So for now it's still wired via the spare 12v feed from the old carb. I just need to find the correct sensor as they can be either normally open or closed depending on how the vehicles circuit is wired.

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Re: Samurai 1.6 fuel pump wiring

Post by ScottieJ » Thu Feb 11, 2021 11:39 pm

Mine's was wired up to an ignition live for years, I chose to just not crash my Sj :er: :hahaha:
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