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Discussion Starter #1
I've got a Suzuki SJ410 1986-model (std carburetor, 997 cc engine), which used to run just fine. But, the old fuel tank was rusty and leaking when filled more than half, so I replaced it with a second hand one which seemed ok, at least it does not leak. Now since I installed the "new" fuel tank, the car runs fine the first 5 kilometers or so, but then it suddenly looses power just as if there's no more fuel coming. This only happens while rolling the wheels. When I let the car rest for about 10 minutes, it goes fine again, some kilometers, and then the same behaviour comes back.

While warm, I've tried running it in neutral at a couple thousand revs for some minutes and then it runs fine too. But one I start rolling, after a short while it just dies again. I've tried emptying all fuel from the tank and refilled with fresh fuel, this didn't help. The fuel filter is quite new, replaced it about a month before I replaced the tank. Have not yet cleaned the carb because I reckoned it should be ok considering the engine runs fine when standing still in neutral.

This problem really puzzles me. Any suggestions?
 

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it mysteriously dies....

since you have gone throught the fuel system pretty thoroughly, i have only two guesses for you:

There is something big in the tank that is getting sucked into place over the fuel pickup while the engine/fuel pump is running. after a few minutes of sitting, the blocking item floats away allowing fuel to flow again for a while.

You have a loose ground in the ignition system that is causing the ignition to cut off from road vibrations.

just a couple of educated guesses, there...

there is an '86/'87 410 factory service manual in pdf format at Ack's FAQ (see link in signature). Do a search for fsm. It's the first link in the resulting search list.

I hope that this helps!
 

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I have a samurai so I don't know a lot about your fuel tank or how similar or different it is from mine. I do know that a lot of people don't hook up their vapor return line properly or it gets plugged by debris. When this happens, a vacuum forms in the tank as the engine draws fuel out of it. If air can not enter the tank through the vent on the vapor return line the vacuum pressure overcomes the pumps ability to draw fuel. When you shut the engine down, the tank will equalize pressure since the engine is no longer sucking fuel out of it. Try taking your gas cap off and see if it still has the problem. If removing the gas cap works, then you need to find out where in the venting system it's plugged.
 

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fuel tank

Very well said. Take the advise to the bank. Hope it's something simple like a plugged vent line or new fuel tank cap
 

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Discussion Starter #6
Follow up

Hi! Many thanks for tha replies so far. I did not write that I tried loosing the fuel cap while this behaviour occurs, to check if the tank is drawing vacuum, but even while riding without the cap on, it still occurs. I don't think it's a vacuum problem but still I could suspect the fuel feed lines. Originally, there is a metal pipe from the fuel tank to the fuel filter, but the owner of the second hand tank that I bought has cut that one about an inch from the tank outlet so I had to replace it with a quite thick rubber fuel line. Could it be that this rubber feed line from the tank to the fuel filter is wrong dimension? It's quite a lot thicker than the original metal pipe. I've got ok clammers on it and checked so it's fitted properly but still.... could this be an issue that the pump cannot draw enough pressure because of the non-standard setup here?
 

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well that seems to eliminate the vacuum theory... The larger diameter fuel line shouldn't be causing a problem, It may need a few extra cranks to get it running when cold starting, but it shouldnt cause it to choke after it's been running a while. Even if you damaged the hard line when clamping it, it shouldn't cause an intermittant failure. I would have to go with either of Ack's first 2 assesments. Something floating over the fuel pickup or a loose ground on the ignition. If this problem didn't start untill after you changed the fuel tank, its probably NOT going to be the ground wire issue, but don't rule it out.
 

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Discussion Starter #8
Thanks again. It's hard to diagnose the tank on the inside, but I'm going to try first putting in a brand new fuel filter, and if it still occurs after that I'm thinking of replacing the fuel tank - again, but this time with a new one. Maybe the second hand tank was faulty... I'm going to keep you updated on the outcome when I know more.
 

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same prob

Sorry about butting in but i got this problem to with my sj410 i have replaced all things on mine due to that i restored it about a year, its had a head new gasket set, new metal and rubber fuel line, fuel filter, ht leads, disruptor cap, posh spark plugs, contact points, coil, even a extra earth wire (the whole thing) now its has been cutting off when i drive it, only once and a while this happens or some times for the whole day, and it is hard to start on the choke:mad: this has been doing this for about 4 months now and iv been talking to my friend who is an x mechanic he says that there may be crap in the carburettor so get a air line take the carb apart and clean it and give it a blow out so don’t bother with red ex, :lol:funny that which is the only thing i have not checked yet lol so i may give that a go this Saturday. Hope this helps (And i all so put a little hole in the fuel cap so it’s not an air lock)
 

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Keep in mind that with Bram the problem didn't start untill he replaced the tank. Logic dictates that the problem would be related to the tank. Since Samurais are anything but logical, it could be anything.
 

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Here is an off the wall question. Are you running a fuel regulator?
I had this same problem when I was setting up one of the Harley systems I tested. The supplier provided a 'less expensive' fuel regulator and when I tried to set it down to where it needed to be, it ran great in the driveway, but as I went down the road it lost pressure. It seemed that the lesser fuel regulator was not designed to run at such a low pressure...
The supplier replaced it with a nice Holley unit and it ran fine after that.

Don't know if that has anything to do with this situation, but I'm throwing it out there just in case.
 

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Discussion Starter #12
Almost solved!

Thought I'd post an update. Last weekend I bought a plastic fuel tank for use with an outboard boat engine (30 liter tank), and connectec the fuel send ine from the plastic tank to the fuel filter, and still let the return fuel line go back into the old tank, because the boat tank has no fuel return inlet. With this setup the car ran perfectly also on the road!

So now I'm sure it's a problem inside the tank, something with the fuel send pipe inside the tank or something.

So now I'm looking - once again - for a replacement tank think I'lltry a new one this time either a plastic one such as the Petroworks, Drive Train - PetroWorks, or one like this if they have one: Fuel Tanks for your 1985-1989 Suzuki Samurai
 

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...I don't think it's a vacuum problem but still I could suspect the fuel feed lines. Originally, there is a metal pipe from the fuel tank to the fuel filter, but the owner of the second hand tank that I bought has cut that one about an inch from the tank outlet so I had to replace it with a quite thick rubber fuel line. Could it be that this rubber feed line from the tank to the fuel filter is wrong dimension? It's quite a lot thicker than the original metal pipe. I've got ok clammers on it and checked so it's fitted properly but still.... could this be an issue that the pump cannot draw enough pressure because of the non-standard setup here?
It could be that the rubber tubing that replaced the original steel tubing is collapsing from the suction pressure of the fuel pump. This assumes that your 410 engine is using a camshaft-driven fuel pump like the 413's engine. The collapsing may be increased by a sharp bend in the rubber tubing.

It may be that the outboard motor tank has stonger/reinforced rubber tubing designed to not collapse under suction or the line is not severely kinked as you have set it up...

It sounds like you need either a combination of steel line (for the sharp bends) and short lengths of rubber hose where the old steel line was OR a new/gently used tank with the original steel line in place.

I hope that this helps!
 

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Discussion Starter #14
Going to check that!

It could be that the rubber tubing that replaced the original steel tubing is collapsing from the suction pressure of the fuel pump. This assumes that your 410 engine is using a camshaft-driven fuel pump like the 413's engine. The collapsing may be increased by a sharp bend in the rubber tubing.

It may be that the outboard motor tank has stonger/reinforced rubber tubing designed to not collapse under suction or the line is not severely kinked as you have set it up...

It sounds like you need either a combination of steel line (for the sharp bends) and short lengths of rubber hose where the old steel line was OR a new/gently used tank with the original steel line in place.

I hope that this helps!
Thanks Ack! That was an interesting tip. The line I drew from the boat tank to the fuel filter was not the same one that I used from the old tank to the fuel filter. From the plastic tank I drew a 3 meter new rubber line, with gentle curves. It may be that the other one I drew from the steel tank to the fuel filter collapses although it's hard to check while driving :) My SJ410 does have a mechanical driven fuel pump. This is definitely worth a try before buying a new tank! Will keep you updated.
 

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Discussion Starter #15
Fuel tank problem SOLVED!

This problem is now solved, it was after all dirt inside the tank!

I want to inform you about what happened so others can skip the trouble I had. It did not seem logic to me at first but now I know better... So as I wrote earlier, when I got the second-hand tank home I thought I'd better flush it before installing it, and this I did by filling it with 10 liters of fuel, through the inlet hose (tha large pipe), stirring around, and emptying it again through the same inlet hose. I did this at least twice, basically no dirt came out.

But after all the trouble I got and your tips, I finally removed the tank again and loosened the upper cap for the fuel meter instead. Under this cap, on top of the tank, there is a large hole that I emptied the fuel through. And this time a lot of stuff came out that shouldn't have been there!!! So apparently the former owner of the tank had used silocone to tighten the upper cap, and large chunks of silicone had fallen down into the tank. When I emptied the fuel thought the inlet hose, this stuff did not come out because the inlet pipe continues about one inch inside the tank. I did not know this until I saw it from above... so I never got out these chunks before.

Clearly Ack's theory was correct, some pieces of dirt got sucked onto the pipe that would take out the fuel to the fuel filter, on the bottom of the tank, causing the engine to stall. When resting for a while, it ran again until driving a while etc...

So my nr.1 tip for anyone who installs a used fuel tank would be to make sure you clean and flusgh it through the upper hole meant for the fuel meter, not though the inlet hose!

When you buy a new tank this is normally not a problem but in my used tank the fuel meter was installed already so I never gave that a thought at first.

I anyway decided to install a new tank at last because when this first problem was solved, I discovered more rust and leaking also on this second hand tank, so I was fed up and found a new tank instead made in Canada, aluminium one very nice and clean at a good price too.

Tanks for all the help, now the car runs like a champ again!! My next project would be to install Calmini's 5 inch suspension and look for 31 inch tyres :)
 

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I've got a Suzuki SJ410 1986-model (std carburetor, 997 cc engine), which used to run just fine. But, the old fuel tank was rusty and leaking when filled more than half, so I replaced it with a second hand one which seemed ok, at least it does not leak. Now since I installed the "new" fuel tank, the car runs fine the first 5 kilometers or so, but then it suddenly looses power just as if there's no more fuel coming. This only happens while rolling the wheels. When I let the car rest for about 10 minutes, it goes fine again, some kilometers, and then the same behaviour comes back.

While warm, I've tried running it in neutral at a couple thousand revs for some minutes and then it runs fine too. But one I start rolling, after a short while it just dies again. I've tried emptying all fuel from the tank and refilled with fresh fuel, this didn't help. The fuel filter is quite new, replaced it about a month before I replaced the tank. Have not yet cleaned the carb because I reckoned it should be ok considering the engine runs fine when standing still in neutral.

This problem really puzzles me. Any suggestions?
Might be the carb. It will start well but will loose power after some time I had that same experience with a samuri as well u can cross the plug leads and tumble to clean some of the dirth out or take it down and clean it
 

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If you check the post above yours you will see that the problem was resolved - over five years ago.
 

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Jimny fuel pressure issue

Hi guys, I had similar problem on a 1999 Jimny, but..now it wont start at all so I still have issues. It also ran ok for a bit then lost power & would stall then be ok after a short period. I thought it was bad fuel as I had similar issues with a hedge trimmer, mower & motorbike after filling up several petrol cans from the same petrol station. I have taken the tank out 3 times now. Originally I cleaned it out as there was debris / particles in there. My problem is low pressure from the fuel pump. New fuel pumps are over $900, car is neat but not keen on spending that much on it.
Not sure what to do??
 

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I found a brand new stock one at suzukipartsUSA on ebay. fixed the problem although I cut the old one up and found nor reason it shouldn't have worked.
 
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