LUVTruck.com

I recently (about 6 months ago) bought a '79 Luv as a project truck to teach myself a little bit about engines and such. I've learned that in order to get the engine started properly, I have to turn the ignition key to "ON" and listen for the fuel pump to rattle a little...then give the gas pedal a couple of good pumps and start the engine while keeping the gas pressed down for maximum air into the carburetor.

Tonight, the engine started ok but then suddenly died. I popped open the air filter to take a look into the carburetor and noticed that no fuel is squirting out of the fuel injector when I pull the throttle lever. Does that indicate my fuel pump may not be working properly? I remember the other day when I pulled the throttle lever fuel squirted out into the carburetor...but now it doesn't do that and I'm thinking I may have to replace the fuel pump? Unless there's something else I'm missing...I don't know much about engines, like I said I got the truck to give me an opportunity to learn.

If it is the fuel pump, is it a fairly easy thing that I can replace on my own? Or should I look at something else that may be the problem? I did notice that when I turned the ignition to "ON", I didn't hear any rattling from the fuel pump...which is why I think that may be the issue.

Very well could be the issue. Since the fuel pumps make a pretty noticable jpise when they r on it makes it easier to tell. I would try to test it bynputting it to on and put your hand on the pump to see if you can feel it vibrating. The pump is pretty much directly under the gas door bolted in a hoop on the frame rail so if you look up from under neath it ahoukd be right oerhead Its very easy to change one i went thru 4 of them because i ran new wiring to it without a relay or fuse and fried a few..

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

Interesting...I wonder if that's what the previous owner did. Thanks for your advice, hopefully it's a quick and easy fix!

The fuel pump runs when the key is in the start position and then when the alt starts charging. I usually tell people to hot wire the pump and see if the truck runs before replacing the pump. What I do is to hook up a dieter to the fuel pump wire in the plug on the fire wall and check that way.

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Certified pilots, looking down on people since 1903.

By the way welcome to the site

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

You should NOT be able to hear the fuel pump unless you are very close to it & then only a slight hum. You should feel a vibration, not a thump, with your hand against the pump. They can run for a good while after they start getting noisy but they are not running like they are supposed to. They can run but not produce enough volume, they should produce a good constant stream the full size of the fuel line. Generally the cause is dirt, so keep a clean fuel filter before the pump at all times, especially if you have a dirty tank, which you probably do have.
If you test with a jumper be careful about sparks if you have an open fuel line near the connection. I use two wires- a long one from the battery, about a 4ft one from the pump terminal- and connect the two well away from the pump.
Any aftermarket unit 4-6psi will work as a replacement but you may have to drill a new mounting hole. The last one I replaced was about $50

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'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

Test it before replacing. Proper pump for replacement should be Mr. Gasket MG12S. $50 or cheaper online, check rockauto.

It should not be running with the motor off and the Key on ON. It is a safety feature so that if you get into an accident the fuel pump doesn't keep pumping fuel up to the motor. As mentioned above, the fuel pump should run only when the alternator is turning or when the starter is turning. There is a relay or two up next to the bulkhead on the passenger side. That's where the fuel pump wire comes in.

So to test it, snip the hot wire and run another one up to the battery and check to see if it will come on.

If it doesn't then pull the output hose off and make sure. Then replace it.

If it does come on, reconnect the pump normally and then go pull the fuel line off the carb and crank the motor over. If there is fuel there then you have a carb problem.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Where is the fuel filter located? I've never pulled it to check on it...probably one of the first things I should've checked when I bought the car.

There should be an in-line filter somewhere in the supply line between the tank & the fuel pump, mine are about 10" from the pump, but I don't know the original factory location.

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'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

Huh...so somehow the red wire connection got snipped by the fuel pump. Reconnected it and everything's good now! Going to have to make sure those connections stay secure...

Thanks for your help guys, I'm sure I'll have more questions as time goes on. =)

Solder and heat shrink the connection!

Not a bad idea to change the filter also. There are two: one located on the frame near the left rear wheel, and one inside the fuel pump itself. The end screws off and out pops a filter.

Hi there, to reply to your questions you must start with the fuel pump and filter. The fuel pump (maybe two) will be located under the back of the driver's seat (under the body) when it comes out of the gas tank (in a half-round holding clip, with the 2nd one being on the passenger side on the fender well. I put SEE THRU FILTERS on my Luv trucks. Note: be careful to put the filter on right, the arrow must be pointing to the engine. Refer to the NEW ONE, SO YOU'LL UNDERSTAND WHICH WAY THE ARROW POINTS, then also look which way the one ON THE TRUCK faces for confirmation. Hopefully, who-ever changed it prior to you put it on right. At any point if they look old, replace them both (cheap insurance). On my Luvs I found out the fuel pump was plugged (I cut it in half to be sure prior to buying a one ($80), that's when I bought see thru filer replacement. It was better but not perfect. I then cut into the rubber hose itself and found the hose itself PLUGGED. This is because the FUEL eats up the inside of the hose (alcohol added to fuel). SO I CHANGED ALL THE HOSES. So, put truck in neutral with the emergency brake on, then have someone turn key trying to start with YOU UNDERNEATH truck with your fingers touching the gas fuel pump. It should make a buzzing sound (its PRESSURIZING) when the key is turned to the start position). If it does this its correct. You then have plugged filters, bad fuel line hoses, or a weak electric fuel pump.
If this vehicle has AIR CONDITIONING, the alternator could also be a problem, not supplying engine spark. Future note, if the things I have told you don't fix it, maybe a gas tank? Then the BED has to come out in order to get to it. I have now and have had in the past several Luv trucks, these helpful hints came hard. I hope they help you Gary C

You can drop the fuel tank without taking the bed off. I did it about 9 months ago. Disconnect all the hoses, disconnect the wire to the fuel level sender unit, and remove the screws holding the filler neck in place and pull it down on top of the tank. Then slide your jack up under the tank to support it and remove a couple of 10mm (I think) bolts on the front and back end of the tank. Lower it down slowly with the jack, and slide it out from under the truck.

i was having the same problems and it turned out to the bad fuel lines.... im pretty sure

i changed the rubber lines from the filter to the pump and the pump to the metal fuel lines under the cab... (leaving the old line from the tank to filter) now it only putters out on my 10% of the time... i think the problem will completely go away ones i change the fuel line from the tank to the filter...

Not sure if some of you are reading the complete posts but several post up the original poster fixed the problem.

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Certified pilots, looking down on people since 1903.