Draining the fuel tank and what fuel?!

Afternoon from the UK

I picked up a 95? 940 2.3 HPT auto estate a couple of weeks back for ?160 from flea bay. It?s been stood for over 5 years and hasn?t turned a wheel, other than being towed. Got down there to winch it onto my fiends trailer, 3 of the 4 tyres wee flat so we decided to throw a battery in it to see if we could get it started. Much to my surprise and the complete shock of the guy who I bought it from, it started and then drove.

Obviously this means it already has a character and I am officially in love!!

It needs a fair bit of tlc and through stage 0 tune to get it going as a daily but I?m all in with it now.

My question is, what is the safest way to drain the fuel tank?! It has half a tank of 5 year old petrol in it which I don?t really want to run through the engine.

My second question is, given it?s been standing for ages, what fuel would you top it up with? Standard 95 ron or a super unleaded 97/98 ron?! What are the advantages/disadvantages of both?

Cheers
Ben

If you suspect there's gunk on the bottom of the tank I guess you'd have to drop it. If not, the easy way is to disconnect the fuel lines coming from the pump, put them in a canister and and let the pump do the work. Even if you consider dropping the tank I'd empty as much as possible first.
I used 98 in mine before converting to e85, but 95 is fine according to the manual. 98 if the boost is more than stock, resists knocking better.
Changing oil would be top priority.

Look in the tank! It’s going to be nasty. You will have issues down the road and ask me how I know!

Recently went thru this on an old BMW, but only 2 years parked and it had non-oxy 93 in it.
Fuel still smelled of varnish, but after a hand 'syphon' device drew out old fuel it's running good(so far).

* The hand syphon device costs me $8 and another $5 for extra length of hose. This method was easy, altho if you want to do a complete drain(& flush) then follow TestPoint's procedure below.

Easiest and safest way to drain the tank is to remove the hose from the back of the pressure pump, extend it with tubing into a container adequate for the amount of gas in the tank. Jump the in-tank pump and drain it. After draining put a couple gallons of new gas back in and pump it out also. Inspect that gas and it will tell you how bad the tank is.

Here is the original gas that had spent 19 years in my tank.



This is the second effort:



Tank was rusted beyond repair. That was pure gas by the way. Ethanol wasn't around 19 years ago.

Since the 940 fueltank is plastic, rust is not a bad issue. Had my car stad for a year and a half, saw no gunk in the tank when I replaced the pump nex year. If you're dropping the tank you might want to replace the metallic straps that secure it, since they like to rust. New ones were ~30€ each over here, IIRC. The hoseclamps at the tank line fittings are probably also worth replacing.

Thanks for the responses guys!

I have no idea on the condition inside the tank, I?d imagine it?s not brilliant though. I have a 125cc motorbike that?s had the same fuel in it for 3 years and it?s practically orange in colour now!!

The straps on the tank are ok, no signs of rust on the underside at least. I like the idea of dropping the tank completely, I am on a budget but I want to be thorough so anything that costs me extra time without the need for additional parts will be welcomed.

As for pumping out the existing fuel, when you say ?jump the pump? I assume it means disconnecting the wiring from the car and wiring it directly to a battery to run the pump?!

Or figure out the pin-out for it on the fuse panel and jumper it there.

Acke said:

Since the 940 fueltank is plastic, rust is not a bad issue. Had my car stad for a year and a half, saw no gunk in the tank

Click to expand...

Yes correct, but the sending unit will rust, and the fuel strainer will break down severely and contaminate the system. BTDT. Installed a new fuel system from tank pump to injectors

The last fuel tank I drained I used a siphon hose through the fuel filler cap, it got almost everything out. And cost less than $10. I didn't feel like messing around under the car playing with rusty fuel lines.

https://www.summitracing.com/parts/...0v7JCeq6qIuaBlYmiETCMaYJ5MQv8BSRoCQzAQAvD_BwE

keep in mind this for a 240, but you can see the process:

http://cleanflametrap.com/transferPump.htm

So I’ve decided to go down the siphon route.

Ordered a hand pump from amazon for £8.50 and a 20 litre Jerry Can. I’m guessing there’s around 30ish litres in there at the moment, I’ve got another car I can dump the fuel in for the time being which allows me to work on this one.

Had the car up on the ramp last Thursday and the tank straps look good all around, however the area around the tank sender looked a bit crusty, I’m not so confident I could drop the tank and clean it properly without having to replace parts because they are beyond the point where they can be cleaned and refitted.

There is a long list of other issues to deal, chief among which is an oil leak coming from the rear of the engine, suspect rear crank seal or sump seal.

Once I’ve drained the tank as dry as I can, is there anyway of cleaning the inside of the tank without removing it?

You are never going to get the last half gallon out. Siphon best you can then put a gallon of fresh gas back in and siphon it into a clean bucket to see how much junk you have remaining. That will tell you a lot about the condition of the tank. Keep putting fresh gas in and siphoning it out until you are happy.

Way up top photoman327 recommended 'looking into the tank'. I bought a 5 foot fiber optic camera with a light that plugged into a smart phone. Really works at about $12.

Long ago in the colonies there was such a thing as shops that rebuilt radiators and fuel tanks. Between aluminum radiators and plastic fuel tanks they are just about gone. They would flush out the tank and coat the inside with some magic potion that would seal even a rusty tank.

The last radiator shop in Georgia:



The magic potion is still sold in many brands and places. https://www.walmart.com/ip/POR-15-F...edirectid=15693642863272239392410080301008005

I never tried it because you have to rotate the tank to spread it around. I replaced my tank for about $200.

I just reread the thread and forgot you have a 900 series with a plastic tank. The siphon and refill still applies but not the coat the interior of the tank.

So a quick update on the tank draining.

Siphon pump kit and Jerry can all arrived at the beginning of the week and I managed to find some time on Tuesday evening to get it done.

Popped the tubing into the tank, started pumping, nothing happened. Pulled the pump back out and the hose was bone dry!! Decided to send my inspection camera down the filler cap and the tank was almost empty even though the gauge is saying I have half a tank. I put 2 gallons of 97 Ron in the tank and the needle moved up from the halfway mark?! I can only assume the sender unit has given up, for now I will just deal with it as it?s not really a problem for me.

When I do get round to it, is there any way of servicing and repairing the existing sender unit? Had a very quick browse online and they seem to be going for ?70-100!!