Mystery...solved? Chuggy, lurchy, when low on fuel.

[joshivore]

Hi all, here is a mystery I may have figured out.

73 square, FI, recently rebuilt 1600 engine, work done by a good shop. 300 miles on the engine, check up with the shop at 100 miles. Ran like a champion all of those 300 miles.

A couple weeks ago she started giving me some attitude when I'd start driving, like out of first gear, peddle pressed, engine response not immediate, then maybe some lurch or chug. Same into second gear, not as noticeable above that but still kinda not right and not with the previous power.

After a few days it got better and was back to normal. I figured there was something in the fuel line that worked itself out? Didn't think about it again.

Until today, same symptoms. I start looking on here for answers, make my list of things to check, then realize I need to put gas in her. This reminds me that last time I'm pretty sure I was low on gas too. (like, almost to the red, but not in the red, I wasn't OUT of gas.) And it just rained in the past couple of weeks and it has barely rained since the engine rebuild.

I read somewhere about gas being lighter than water so if there is water in the tank it would collect in the bottom of the tank, does that sound right?

So when I'm low on gas my engine starts acting up, does this sound like maybe there is water in my tank? I just went and put gas in the car and she was noticeably better (though not perfect, but I only drove about a mile home, so maybe if there is water in the lines that wasn't enough of a run to work it out?)

I can't remember if it rained before the last episode. If it did, maybe my gas cap is somehow leaking? Seems odd. Or maybe water in tank from condensation?

Any thoughts are appreciated.

[joshivore]

oh, also, maybe related but I don't know how, the rubber....boot? gasket? shoe? around the gas cap inside the fuel door is loose and cracked and not in good shape at all. It doesn't seem like that could be letting water in the tank, but maybe it's worth adding.

[KTPhil]

Yes, the overflow/filler seals are vital to a FI car. Dirt and water will find their way in, including from splash under the fender. The lowest point in the fuel loop is the motor, which can be destroyed by dirt and water. Jim Adney makes a better-than-OEM kit you should install as soon as possible. Also, if water got in, your fuel sock may be rusted or clogged, and your fuel filter may be closed up due to absorbing water.

I recommend you buy lots of new FI hose and clamps, and change out the lines up front, the filter, and the filter sock, flushing out the tank while you are at it. Otherwise you may continue to fight this problem and perhaps have to replace the pump.

I presume they already replaced the rear fuel lines as part of the rebuild, but check those, too.

[joshivore]

thanks KTPhil, does the problem sound like maybe i have water in the bottom of my gas tank in your opinion? i found a filler collar on ISP West, but would love a link to the one you mentioned as I couldn't find anything. will definitely fix that collar soon and replace the lines and empty the tank up front.

[Bobnotch]

[BSQUARE]

You may have sediment in the tank obstructing fuel from getting into the "bowl" surrounding the tank outlet.

The bowl was put in later model tanks to prevent fuel from sloshing away from the outlet at lower fuel levels.
But, over the years, scale and sediment can clog the small openings from the bowl to the rest of the tank, causing the symptoms you describe.
_________________
1988 Ford Festiva L
1965 Honda 50 "Super Cub"
2016 Miami Sun Trike

[joshivore]

thanks everybody. today my car ran great. it had a half a block of chugging and lurching when it started up, but was great the rest of the day. this on again off again symptom, which doesn't happen at idle, is so odd.

thanks for the tips, i will get the needed parts for tank cleaning, filler collar replacement, fuel line replacement and whatnot.

any pro-tips on those jobs? i have a sad history of occasionally breaking things that didn't need to be broken.

[nogoodwithusernames]

My "Pro Tip" is don't try to pull all the old fuel lines out and then have to try to figure out where everything went. Just go through and do one section at a time! (Also don't do it with a full tank of gas! Empty it into a gas can first.)
Other than that it is a fairly straightforward job.

Maybe call around a few places to see who has the cheapest FI line, since it can get pretty $$$ at some places.
_________________
71 Squareback, 1.7l T4 w/ crank trigger fuel and spark
(Conversion thread https://www.thesamba.com/vw/forum/viewtopic.php?t=732508&highlight= or https://shoptalkforums.com/viewtopic.php?f=1&t=151375&sid=f0542d44a322d290c29d6609fac7f215 )
74 914, 2.0L w/ D-Jet

-Derek

[Mike Fisher]

You don't need to buy fuel injection hose, just reinforced rubber fuel hose like Gates/Goodyear. Strain your gas through a T Shirt to filter it for reuse.
_________________
https://imgur.com/user/FisherSquareback/posts
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold

Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey

[Bobnotch]

[D/A/N]

[KTPhil]

[W1K1]

Gates 27340 Barricade is rated high enough pressure for the FI system

http://www.amazon.com/Gates-27340-Barricade-Fuel-Line/dp/B0053OSB90
_________________
http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap