outersketcher

My XJ has been sitting for more then a year. I have... or had... about half a tank of unleaded gas in the tank when I pulled the engine. Now I'm worried that my newly rebuilt engine will refuse to fire up when trying to suck on that dank tank.

Suggestions?

Slip a hose into the tank... suck on it and drain the old fuel?

or.. just add a few more gallons of fresh gas and a bottle of stabil?

jordan96xj

Its not uncommon for new motors to have a few issues when first starting up. You don't want bad gas to be a variable that you are guessing about when troubleshooting. So siphon the old gas out, put new gas in. Then use the old gas for your lawn mowers and stuff, or gradually add it back to the vehicle's tank over a few fill ups after everything is working normally.


Stabil used after-the-fact won't help very much, if at all.

PatHenry

As usual, Jordan is spot on.

I will say, I had gas in my old TJ and it had been sitting for 2 years - I fired it up and it ran great. In your case, the likelihood of having wonky stuff happen after the new engine goes in is more than enough reason to siphon and use fresh, clean gas from a reliable source (I'd use gas from the station you most commonly use).

outersketcher

got it!.. kay... wheres that siphon tube..

BlueRidgeMark

Yeah, I'll pile on here. What they said.

Wouldn't hurt to put some Stabil or other quality gas treatment in there for the first tank, just to help with whatever you weren't able to completely clean out.

Bugout4x4

You might not get a hose down in the filler tube to the fuel, These have a roll over check ball caged in the fill tube that blocks it off for hoses. I had to unhook the vent hose and use a very small diameter hose down through it into the tank if I remember right.

jordan96xj

Another way to empty the tank is to disconnect the fuel line that goes from the pump to the filter (disconnect at the filter) and run that line into a container. Then jump the fuel pump relay to manually turn on the pump. It will pump the gas into the container. It would be best to turn it off the moment that things run dry.

Bugout4x4

Absolutely. And hope that junk doesn't clog up the in tank screen. If the fuel is only a year old this shouldn't be an issue though.

outersketcher

The fuel is about 14 months old. I think what I'm going to do is just add several gallons of fresh gas. hip bump the XJ a few times to slosh the tank and give it a go.

Bugout4x4

I would at least unhook the line to the fuel rail and pump the line clear first by cycling the key several times after you dump in the new. The line takes the biggest hit from sitting like that and you want fresher fuel up there to start with.

outersketcher

good point.. will do.

Bugout4x4

Should be able to smell when you have it clear. There is a huge difference. lol

outersketcher

I enjoy restoring those old trail bikes from the 70s.. you know.. those Honda z50's. CT90s.. CT70s.. and so on.

I have developed a special hatred for the ethanol that the government forces us to put in our gas.

That stuff gums up every carburator, clogs every jet, plugs every screen within months of inactivity. Any motorcycle I forget to drain the gas tank, and empty out the bowl in the carb. Will invariably end up with me having to spend time doing a full tear-down and rebuild of the carb to get it to run again.

Bugout4x4

Oh yes I know. My first "real bike" after briggs and stratton minibikes was a QA 50.

You are real familiar with tank sealer then. lol

mannydantyla

If it was me, I would put in new gas and maybe pump out the gas that's sitting in the lines, but I've also been told by old timers that gas these days doesn't go bad like it used to.

With a new engine you want it to start up right away to get oil to the flat tappet lifters and cam. For our 4.0 engines, the cam lobes get oiled from oil "squirters" on the piston connecting rods, and I'm not sure if idle RPM is enough to effectively oil the cam but in general the higher the rpm the higher the oil pressure the better everything gets oiled. That's why the break-in procedure for new cam shafts and lifters is to idle the RPM around 2,000 for at least 20 minutes. And it's better to vary the RPM.

And yes I'm the guy who just put new lifters on an old cam and didn't do any sort of cam break in procedure. So you might be wondering why you would be listening to me, but after learning of this mistake I've been reading all about it the last two days and now I know all about it. You want regular oil, not synthetic, with a ZDDP additive. Very important! You can use an oil with a lot of ZDDP in it already like racing oil or diesel oil i.e. Shell Rotella, but I've read that the high amounts of detergents in Rotella competes with the ZDDP. That said, I'm now using Rotella T4 in my new-ish engine, so that tells you how seriously I take those racing oil experts. I mean, unless your engine is a 4.6L stroker with progressive valve springs and an aggressive cam, I don't think it's as easy to ruin a camshaft as the hot rod guys makes it sound. Sure it does happen including stock 4.0s, but I don't know if it happens as often as some folks will have you believe. Maybe I just got lucky though, idk

If you're cranking and its not starting, put the pedal to the floor and keep cranking. That will put the PCM in "clear flood mode." I've had to do that once or twice.