Reserve Fuel Tank?

Hi,

I'm not sure what you are asking. There isn't a separate fuel tank that is for reserve. If you are not getting fuel, have you checked fuel pressure to see if it is within the manufacturer's specifications?

If you haven't, here is a link that explains how in general to test fuel pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the pressure specifications below. Let me know if this helps or if you have other questions.

Take care,

Joe

See pic below.

The car has on numerous occasions left me stranded with half a tank when reserve runs out of fuel. Have replaced the fuel pump and fuel filter. Still the gauge drops to empty and cuts the car out meanwhile there is half a tank of fuel. My son noticed a nozzle or pipe leading from the reserve to the main hold tank. I think this could be possible blocked. Right now, I keep on filling up 26 liters every time it's a 45 liter tank.

When the gauge drops to 0, does it happen all at once and then the vehicle stalls? If so, that sounds like a connection issue at the pump assembly.

Let me know if that is what happens.

Joe

Yes, the car starts to stutter, letting you know it's about to run out of fuel. However. Then I go to the nearest filling station, I fill up or give them R300 and then it rises all the way up to half again. Something is off and I just can't put my finger on it. Next step is the sender unit. I have in the interim run a hose from the remaining tank into the reserve so that the fuel can be reached by the pump at all times.

Hi,

There are two things I can think of. First, since the fuel gauge drops to 0 when it happens, it sounds like there is a connection issue. Have you checked the wiring at the pump?

As far as the pump itself, there is a filter at the bottom that could be partially plugged. See pic below.

Let me know your thoughts.

Joe

Hi apparently the wiring was checked and all is OK. Apparently everything wasn't in working order however I'm still using stupid amounts of fuel very quickly. I must mention that the tank has rust and the car stood for 4 years. Also the injectors have just been done a week ago. My next conclusion is the sender unit is faulty at half. Or the floater. If I had a clearer picture of the inside of the tank I could understand the mechanics of it. How does the remainder of the fuel get into the reserve compartment area where seemingly all the problems are. There is a small pipe intake or outtake from the reserve and curves in a C bend around the reserve and goes somewhere I have no idea. In order to solve the mystery. I will stick to my mock up plan until I can source a second hand tank and a complete new pump assembly unit.

Hi:
I attached a few pics below to help you understand how it works. However, pic 1 is for me. LOL Do you see what you are referring to as a fuel reserve compartment? There really isn' a tank for that. Let me know.

Okay, in pic 2, I circled the float. It is mounted on the fuel pump module. Basically, it is a rheostat or thermistor. As the fuel level drops in the tank, the float moves downward. When you add fuel, it moves up.

If you look at pic 3, that is the level float. Power is introduced to it via pin one in the connector. Power goes through the rheostat which functions as a resister. Based on the level of fuel on the tank, a certain amount of voltage is sent via pin 4 in the connector. That voltage is what determines the fuel gauge indication.

Let me know if this helps. Note, pic 2 is from is for a single overhead cam model. If you have a dual overhead cam engine, let me know and I'll get you the other pic.

Take care,

Joe

See pics below

Hi Joe,

Thanks for the pics. I'm ready to set this car on fire. I got stuck on the side of the road again with sparks coming out of the exhaust.

A tank that is supposed to produce between 500 to 600 kilos is giving me 352 as per the pic which makes no sense.

The reserve in this tank is a 10cm high square unit in the tank with an outlet going somewhere.

My temporary fix at least helped me get way more mileage but still left me stranded. I then topped up with 15 liters for the needle to rise to just over half again.

The problem seems to be at half. Or as has been suggested that the floater is too short to reach the lowest level of the tank and then reads through to the engine that there is no fuel left over meanwhile there is about 5 to 10 liters.

Hence it would have been nice if someone somewhere actually had the gall to chop open a tank so that I could understand once and for all how it works and what is causing the problem.

But at this rate I'm going to set it alight. It's causing me huge amounts of frustration and heartache which I don't need because I keep on having to have standby fuel and can't actually afford it anymore.

I only earn 10000k a month in South Africa, and our fuel is at an all time high of R24 per liter. I drive 60k's a day.

This car has over 300,000 on the clock.

Thanks for your time.

Hi,

I'm concerned about the sparks from the exhaust. That sounds like the catalytic converter is coming apart. Was it backfiring or anything?

Joe

Hi Joe,

No backfiring like a loud bang. After I had stopped to re-fuel I drove off again and there was nothing. It could also have been the car before me dumping a cigarette out the window.

Who knows?

LOL

I suspect that is a likely cause. You had me a bit concerned. I've seen plugged catalytic converters do that. Eventually, it would cause a fire. Ugh! I didn't want that to happen.

Regardless, take care of yourself, and please feel free to come back anytime in the future.

Joe

Thanks for the response. However we still haven't solved the fuel starvation issue. And I was hoping that someone had a answer for me or a solution or a picture of the inside of the tank to understand the dynamics.

Neither here nor there.

Keep well

Hi,

I wish I could have been of more help because I don't like to be beaten by a vehicle. LOL

However, if the vehicle stalls out at half tank, the only thing I can think of is the filter at the bottom of the fuel pump is partially clogged and not allowing fuel to enter after a certain level. Nothing other makes sense.

I'm still confused about what the reserve tank is. I have gone through several exploded views of the tank and components, and nothing is listed.

If you take a look at the pics below, do you see the component you are referring to?

Let me know.

Joe

See pics below.

I hope this will help what I see and feel when I've got the lid off into the tank.

Do the actual fuel lines go to those things or could they actually be the charcoal canister?

Let me know.

Joe

I have no idea. My investigation is still around is that the reserve and how does the rest of the tank flow into the reserve once it starts heading down to low and nearly empty.

If the "reserve tank" in the pic you made is mounted near the tank and not in it, that is most likely a charcoal canister that traps fuel vapors from escaping into the atmosphere.

Do me a favor. Carefully disconnect one of the hoses at the "reserve tank" and see if there is fuel in it. If there isn't, suspect the sock on the bottom of the pump is partially plugged.

Let me know.

Joe

Pic is from inside the tank as you drop the fuel pump assembly unit into the tank. There aren't any internal hoses. Maybe below the tank on the outside yes. But none inside the tank even remotely resembles a hose.

Next option could be that the floater isn't long enough to give a proper reading. Or that the tank at some point was changed to a 25-liter tank.

I'll take pictures tomorrow and send them to you. Also, will get proper test done on assembly unit specifically the sender unit.

I'll keep you posted.

Hi,

Anything is possible as far as the tank. Maybe the pump isn't reaching the bottom of the tank.

I attached the pic you made below. What is this that I circled?

Let me know,

Joe

See pic below.

That is a metal pipe that is part of this "reserve" section that is made of metal. It is part if this section and is not an attached section to the tank. It also curves in a C around the "reserve tank" I had huge amounts of carbon smoke this morning that looked like condensation.

So, if the pipe to the carbon box is dirty or blocked will it have a huge effect on the regulation of the fuel inside the tank?

And if the carbon box is dirty, will it also affect a lot of the problems experienced?

Hi,

The canister is an emissions component that is designed to accept fuel vapors from the tank. At specific times, the fumes from the canister are vented into the engine to be burned with the fuel. It wouldn't cause the issue you have with running out of fuel at half tank. However, if one of the vents is stuck open, it could cause a lean fuel mixture.

You mentioned carbon-colored smoke. Was it a blackish, gray color?

Joe

Grey color. I've had fun the past two weeks.
The car started stuttering on 3 pistons. Had fuel injectors reconned. R2500 later.
A week later major fuel consumption and heavy grey smoke.
I pull the spark plugs reset the ECU, grey smokes stops dramatically but a week later running on 3 pistons again.
Contact the mechanic that did the work only to get told to get lost.
Off to a MRI mechanic checks the fuel injectors. No 1 has gone will need replacement. R800 later.
Buy plastic second hand tank and fuel pump assembly R1000 later.
Firm I work for helped me buy the tank but can't pay for the injectors no budget right now.
Being driven to work.
Never ending project. Never ending owing and borrowing money.
Will keep you posted after all is done and replaced and take it from there.
Here's to my little project that is keeping me on my toes.

Wow, you have luck like me. LOL

If the smoke is gray, it's getting too much fuel. Did you have a chance to check the fuel pressure and the regulator? Also, confirm there is spark at the affected cylinder.

I will watch for your reply.

Joe

Dear Joe,

Grey smoke - too much fuel - injector no 1 has gone even after the recon - more money
I bought a plastic fuel tank thinking it was going to be an in out scenario only to find it wouldn't fit.
Attempting a bicarbonate and vinegar flush on the tank - which should have been followed through with a diesel rinse - was never done.
I'm truly overwhelmed by people's inability and ignorance.
Stuck with the old tank - rust will build again.
Tried to flush out the fuel line pipe that follows to the reserve thank - such a bad design. See diagram of how it works.
Fitted a secondhand sensor and floater unit and filter let's see how it goes. I'll have to on a monthly basis pull out the pump and see what the tank is doing.

Hi,

I have no idea the purpose of the "reserve". What is indicated is no fuel from the outside can enter it. Could it be some type of baffle that prevents the fuel from sloshing around?

Also, the tank in the pic appears to be plastic, or am I seeing it wrong?

Let me know.

Joe

Morning Joe,

It's literally a bowl that the pump sits in and then sucks the fuel through that stupid pipe in the picture. So, if the fuel isn't shaken around in the car regardless, I will always run out of fuel because we weren't able to manage blowing it open. Or rather I didn't get the help I needed to get it done.

It is what it is.

Yes, that tank is plastic.

Hi,

That is an interesting design. One that really makes no sense to me, but I'm not a design engineer. LOL What is interesting to me is they call it a reserve tank.

Regardless, let me know how things turn out once you get everything together.

Take care,

Joe