Fuel Issue

[MrPotatoHead]

So I've been driving around Australia while I'm on long service leave, done about 10,000 km so far with no issues whatsoever. Today I ran the tank lower than I think I've run it on the trip so far and ran into a bit of a problem. At an indicated 100km to empty (10L left in the tank), the car just decided it didn't want to accelerate any more. It would drive at very light throttle applications, but put the foot down at all, and it felt strangled (actually went slower). At no point however did it stall or cut out completely. Luckily I was only a couple of kilometres from my destination, and I limped into the first petrol station I saw and filled up. When I fired it up again, it ran rough for a few seconds, but seemed to burn through the "bad" fuel and once it picked up fresh fuel it was all good again.

My question is, was it something in the bottom of the tank? water? bad fuel? I've run it down to about 70km to empty in the past with no issues. I had 10L of fuel remaining (put 54L in) so it shouldn't have been picking up the dregs so to speak. Will it just burn through it over the next few tanks? Or if its something like water is there something I can add as a co-solvent (ethanol?) thats not going to mess with the engine.

[Kekotic]

From what I know from google (yes John...it's how people these days learn!) from a while back when asking a similar question hypothetically on a different forum, I was told that the fuel pump receives fuel from the bottom section of the tank anyway, so there is no 'sediment' or 'bad fuel' at the bottom of the tank like some people claim. This could be wrong of course, because it's from google and not your local mechanic

Due to your circumstances (re: driving around Aus) maybe the fuel isn't the problem (not counting whatever reads the fuel), and something else is?

Just a thought from someone extremely uneducated on cars, so basically disregard this when youngy/dropz or one of those guys comes up with something better.

[Nottage969]

I know when i went "puddle hunting" in my old car and managed to get some water into the engine from sucking it up through my air intake, it ran exactly like that. I managed to limp it home but then couldn't restart it or anything for a couple of days (luckily for me the water basically dried ITSELF out), and i was able to get going again. It ran rough for a minute or so, and then was back to normal. (I've never been puddle-hunting since ).

However, all i'm saying is that your symptoms match those of water getting into your engine, because i wouldn't have the foggiest what else it could be or how you could've done it! Another un-educated reply, wait for Dropz or someone like that to drop the solution!

[Dropz]

Hehe, just read through, nice to see my name popping up

Similar to your thoughts, and whats been said, it sounds much like a fuel issue. From what you've said about it occurring with low fuel and the symptoms disappearing after a full tank I would be suspicious of having condensation in the fuel tank. As it is only a small volume compared to the fuel quantity it would float on the top, and when the fuel level is low and the fuel moving around with G forces it may pick up a bit of water/condensation here and there.

Did you get any dash lights or any other symptoms at the time it happened?

[Jtek]

Not saying you're wrong Dropz but isnt water denser than petrol causing it to sink to the bottom of the tank? In saying that, it wouldn't matter if the tank was full of fuel or not because the pickup is near the bottom off the tank. No other causes coms to mind though When was the fuel filter changed last?

[Ric]

Old bit of bushies advice.
To get rid of water in your tank, pour a cup of metho into your tank.
That will mix with the water, and allow it to pass through the engine slowly.

The other option is to chuck a fair bit of E10 fuel into your tank, which will have a similar effect.

[Dropz]

I've found that miniscule amounts would tend to float as there isn't enough to outweigh the fuel and cause it to sink. I've seen the same with oil drains that get a bit of coolant or water splashed on top.

A tank of E85 would help flush it out.

[MrPotatoHead]

No other dash lights or anything came on at the time. I've just run most of the way through the tank of fuel again (down to ~160 to empty) with no issues so far. If it is condensation then ethanol will do the trick, is it safe to run e85 through the H6? Its tuned for 98

[Dropz]

It'll be ok for a tank. Just see how it goes again though, I'd run it lower than it was last tank if there are no issues, just to see for comparisons sake how the car responds and if it happens later again.

[smythie]

unless you have had it tuned specifically for it, I'd strongly advise against it: you need to run a LOT richer for E85 AFAIK and the ECU is not capable of auto detecting and compensating.

[Dropz]

For one tank I've never heard of anyone having issues. For extended use or hard driving certainly yes get a retune.

[BUDDAH]

If you ever owned a boat you would know how hard it is to keep water out of the fuel tank apart from physically removing the tank I would use a bottle of Chemtech Petrol Power - Fuel Additive available from Bias Boating

Adding metho e10 e85 just didn't work for me . After getting a gut full of water you will find your petrol filter is rooted.


To the OP I doubt water in you fuel was you problem ( the engine would just STOP) although a new fuel fix it I would say the engine was starving for fuel so I would be looking for a blockage on the fuel line pick up.

[MrPotatoHead]

But if it runs fine now at full throttle then that blockage would no longer be there. Maybe I should just run this tank down and see if I run into the same problem again...

[BUDDAH]

But if it runs fine now at full throttle then that blockage would no longer be there. Maybe I should just run this tank down and see if I run into the same problem again...

Could be something neutrally buoyant still floating around inside you tank that may or may not ever be a problem again.

[Dropz]

To the OP I doubt water in you fuel was you problem ( the engine would just STOP) although a new fuel fix it I would say the engine was starving for fuel so I would be looking for a blockage on the fuel line pick up.

Water won't always kill the engine completely, it depends how much water there is in the system, it may only get water in one cylinder at a time causing misfires, or it may only be a minute amount and run lean. It's all pot luck.