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New Samurai owner, new elec. fuel pump, hooking up fuel pump cutoff

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Hello everyone, I've been reading a lot here over the last month or so, but this is my first post. I recently bought an 88.5 Samurai Soft top, with very little knowledge of the 1.3L (or any engine for that matter.)

It has a Weber Carburetor & I decided i wanted to do an electric fuel pump rather than replacing the mechanical. I am running a Mr. Gasket 42S, mounted at the stock fuel filter along with a clear filter so i can see if there is junk in the gas before it hits the pump. It is run into the two-outlet jeep fuel filter in the engine bay with the return line plugged into the smaller diameter output; it is just above the existing plastic clamp for supply and return hoses on the engine, so within  12" or so of the carb.

I intend to hook the pump up to a Fuel Safety Switch plugged into a tee with the Oil Pressure Sensor; i now have the BSPT -> NPT adapter and the rest of the fittings i need, I just want to make sure I am mounting it correctly. Now skip to the most recent post :)

Update: Cleaned this post up and updated.
« Last Edit: June 29, 2010, 12:07:08 PM by Schigolch »

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Online fordem

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Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #1 on: June 22, 2010, 04:46:06 AM »
A couple of points ...

First - don't feed the fuel pump from the ignition coil - find an ignition feed in the fuse panel and use that, run a wire through the firewall if you have to.  The ignition coil's negative post is normally connected to the distributor, so your connecting the pump there will prevent the distributor from producing a spark, and the engine will not start.

Second - the oil pressure port on the block is 1/8" BSPT - the nipples and most of the tees etc., that are commonly available are 1/8 NPT - you need an adapter which should be available from any of the gauge manufacturers.  Also you do NOT want to stack an array of adapters, tees, switches & senders off the side of the engine - the brass will fatigue & break - mount the tee on the chassis and run a flex line from the port to the tee.
'98 SQ420 Grand Vitara
'05 JB420 Grand Vitara
'16 APK416 Vitara
'21 A6G415 Jimny

Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #2 on: June 22, 2010, 09:44:37 AM »
Thank you very much! I thought that I wouldn't want that wad of brass hanging on the side of the block but I wasn't sure what would be a good way to move it farther away.

Time to get the wiring diagram back out.

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Offline Drone637

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Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #3 on: June 22, 2010, 11:13:40 AM »
Do you know what the webber requirements are for a fuel pump?  I know the Stock SJ-410 side draft wants 5lb of pressure so 3.5 might not be enough to get started.  I use a 8lb in-line pump similar to what is mentioned in Ack's Faq and finally connected a pressure regulator.  Now she runs like a top, before that it had a habbit of flooding out due to the excess psi on the line.

Instead of bypassing the manual pump what about just reconnecting the stock fuel lines?  Have you tried blowing them out to see if they work?

For powering the electric pump I setup a relay and run that off an ignition source.
96 Geo Tracker, x-SJ-410,  x-White Rabbit, x-Project Trouble
Crawlers NorthWest
x-Trouble Racing

Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #4 on: June 22, 2010, 01:10:12 PM »
From what I have read about the weber 32/36 on the 1.3L, 3.5 is high if anything, Manual recommends 2.5-3 but I believe closer to 1psi is recommended around here by sarge/skyman/et al.

In retrospect I should have perhaps replaced the mechanical pump and reconnected the stock lines, I believe the stock fuel line is serviceable and the return line intact, but now I have the electric pump installed i want to at least get it figured out before I bail out.

Now that fordem explained the threading for me I will be able to hook up a fuel pump safety switch next to the oil pressure sensor, and that will give the fuel pump juice from the ignition or starter solenoid depending on what is happening at the time. Instructions I intend to go by for the switch installation are here.

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Offline Drone637

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Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #5 on: June 22, 2010, 04:57:25 PM »
If your over-pressuring the Webber it might be flooding.  I would pick up a pressure regulator, your local auto part store should carry one.  Autozone has them for around 25 bucks with multiple nipples, check in the V8 section next to all the chrome parts and universal fuel filters.
96 Geo Tracker, x-SJ-410,  x-White Rabbit, x-Project Trouble
Crawlers NorthWest
x-Trouble Racing

Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #6 on: June 25, 2010, 08:51:57 AM »
It looks like the weak coil was indeed a problem, I went ahead and got the pump working by hooking up a relay powered off of the Vacuum Switching Valve wire that was hanging out unused. Jumped it, and it ran! My fuel pressure gauge at the carb was showing something like 6 Psi though, which threw me off since the pump is only supposed to push 3 psi, so I think my return might be clogged, I'll have to try blowing it out on Sunday.

That, and my t-case decided to get stuck in neutral - so I'm ordering the shifter sheet replacement kit today, and will mess with it on Sunday just to get it into gear and rolling in the mean time.

Thanks for the help guys!

Re: New Samurai owner, new elec. fuel pump, new problem starting
« Reply #7 on: June 29, 2010, 12:03:01 PM »
Second - the oil pressure port on the block is 1/8" BSPT - the nipples and most of the tees etc., that are commonly available are 1/8 NPT - you need an adapter which should be available from any of the gauge manufacturers.  Also you do NOT want to stack an array of adapters, tees, switches & senders off the side of the engine - the brass will fatigue & break - mount the tee on the chassis and run a flex line from the port to the tee.


Hi Fordem (or anyone else) - for a flexible line to mount the tee with the oil pressure sensor and fuel cut off - will this oil pressure gauge kit(clicky) work, or should I use something more substantial?  I figured I will cut it down to 18" or so and clamp the tee with the sensors over onto the stock jack mount, since it is a big convenient piece of sheet metal.
« Last Edit: June 29, 2010, 12:16:57 PM by Schigolch »

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Re: New Samurai owner, new elec. fuel pump, hooking up fuel pump cutoff
« Reply #8 on: June 29, 2010, 03:11:41 PM »
That is probably a 1/8 NPT fitting and will not screw into the block - I'm also not too keen on nylon tube, it has a way of developing a "weep" over time and making an oily mess - you can get similar kits with copper lines.

This fitting will screw directly into the block, but the ferrule is for a 4mm line so it is too large for 1/8" - you can use the 1/8 ferrule that comes with the kit for a perfect seal.

If you do use copper lines, be sure to wind a couple of loops between the engine and the T so that it flexes when the engine moves, and doesn't break.
'98 SQ420 Grand Vitara
'05 JB420 Grand Vitara
'16 APK416 Vitara
'21 A6G415 Jimny

Re: New Samurai owner, new elec. fuel pump, hooking up fuel pump cutoff
« Reply #9 on: June 29, 2010, 06:23:11 PM »
That is probably a 1/8 NPT fitting and will not screw into the block - I'm also not too keen on nylon tube, it has a way of developing a "weep" over time and making an oily mess - you can get similar kits with copper lines.

This fitting will screw directly into the block, but the ferrule is for a 4mm line so it is too large for 1/8" - you can use the 1/8 ferrule that comes with the kit for a perfect seal.

If you do use copper lines, be sure to wind a couple of loops between the engine and the T so that it flexes when the engine moves, and doesn't break.


I picked up a BSP -> NPT adapter to take care of the block, so i was going to plug into that with the 1/8 NPT - thanks for the note about nylon, I'll pick up copper instead.

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Re: New Samurai owner, new elec. fuel pump, hooking up fuel pump cutoff
« Reply #10 on: June 30, 2010, 06:06:39 AM »
Water under the bridge but I'll take a bet you paid more for that 1/8" BSPT-NPT adapter than you would have for the pair of fittings I linked to - including the shipping.  ;)
'98 SQ420 Grand Vitara
'05 JB420 Grand Vitara
'16 APK416 Vitara
'21 A6G415 Jimny

Re: New Samurai owner, new elec. fuel pump, hooking up fuel pump cutoff
« Reply #11 on: June 30, 2010, 10:00:49 AM »
Water under the bridge but I'll take a bet you paid more for that 1/8" BSPT-NPT adapter than you would have for the pair of fittings I linked to - including the shipping.  ;)

at $4.50 + shipping from the UK I think it might be close enough to not worry about :)