Inaccurate fuel gauge almost leaves me stranded!
 

So I'm on the highway opening her up and right before the tach hits redline the engine just loses power, almost like it hit a rev limiter at about 6.5k rpm. I knew something was up right away so I threw it into neutral and just coasted to the next off-ramp. Right away I looked at my fuel gauge and it's sitting at 2 dots, warning light isn't even going off yet! Couple seconds later the warning light goes on. On my way coasting to the gas station any time I gave it gas it was bogging, even died on me but I was able to start it back up. Then, I look at the gauge once I get closer to the gas station and it's at zero all the sudden! I'm thinking POS gauge, it goes from 2 dots, to dying on me, to zero dots in like a 1 miles span. So I fill her up and bam, runs like normal. I've had some issues earlier in the spring putting gas into the tank, after 1 click-off from the gas pump I usually always turn it back on till the second click to top it off. Earlier in the spring when I tried doing the the gas overflowed outta the tank onto my bumper, after only one extra fill after the fist click! I never had that problem before and it shouldn't do that after one click, I'm thinking maybe this has something to do with the fuel gauge issue. And I was going in a completely straight line with this happened, although I had just come out of a tight on-ramp taking that right turn pretty hard, but I doubt that will cause the infamous gas starve issue on this car since the problem happened right after the corner,and it was a constant issue all the way up to the gas station, right?

once starved it does act fairly funny, I tend to use the fuel gauge on my torque app on my phone as it tells me percentage of fuel left according to ecu vs dots.

Well my guess is there's something wrong with the computer that tells how much gas is left, therefore wouldnt the torque app be showing the same thing as the in car gauge? Can the fuel starve issue happen in a straight after a corner, and would it set the fuel gauge to zero? I'm just trying to find out what's going wrong so I don't run into this problem again.

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havent had an issue with my fuel gauge yet. I was coming home from work friday and had 1 dot left and the remaining distance said -- -- so I was scared as ****, but I managed to sit at 3 4 way traffic lights which felt like an eternity and still made it to a gas station. I dont know if any of this matters, but whenever i put my gascap back on i always click it 2-3 times. Always use the same fuel from the same gas station and randomly put additives in about once a month or so and ive never had issues. But Its been really accurate for me. My 09 I was wary about though..... I would stop the car with 5-6 dots, start it the next day and it would have 4. then get to my destination and it would have 5 again....... so its probably one of those shitty quality part issues with nissan like the CSC, some work, some dont.

Could this have been fuel starvation? I was taking a right hand turn on-ramp pretty hard but it didn't start to die immediately, it started when I almost got to redline right after making the turn.

with only 2 dots and under hard/full acceleration that little fuel cup/bucket can be drained faster than it fills up

Probably a safe bet to never do that under a 1/4 tank of gas so you dont lean out and break something expensive

Yea, that sounds like you had the right hand turn fuel starve problem.

My car will do that on the track if it's below 1/2, go I would also bet thats what it was. I have to fill the car up after every other 25 min session at Sebring or the car does it coming out of turn 17 every time.

that is definitely fuel starvation. the gauge acts up during fuel starvation because the gauge is not made to provide instant feedback. if it had instant feedback, the gauge would be dancing up and down like a light show during the entire drive as fuel sloshes all around. so its not made to react to sudden changes. it displays an average of what the fuel sensors are reading. if the fuel on the passenger side goes empty due to fuel slosh causing fuel starvation, the gauge will go to zero, but not right away since it is "dampened".

Ok my question on fuel starvation, how does it leave some people stranded? If it get starved from fuel its only because for that small period the fuel is sloshed to another side of the tank, but after the fuel moves back shouldnt the car then operate perfectly fine?

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the gas tank is divided into 2 halves, bridged only at the top. once fuel goes to the driver side, the only way to get it back to the passenger side is to either slosh it back with a hard left turn, or wait for the fuel pump module's secondary function of in-tank transfer to slowly pull it back. however, if fuel pressure drops, the module cannot transfer it back because the siphon is powered by fuel pressure.

Does a return system do anything to help the fuel starve issue? Just wondering if the fuel in the return line acts as an additional buffer.

Just take easy right turns when you're down to 2-3 lights.

Sent while driving!

Return systems wont help at all.

A larger fuel pump than the engine needs might aid to some *slightly* measurable amount. This is because a greater return volume and higher bypass fuel pressure can boost the venturi's vacuum a little and speed up the fuel recovery time. This would not do anything to prevent the sloshing away. But it could increase the volume of fuel around the pump before it sloshes and help it collect some more fuel before the next turn. I wouldn't do a pump upgrade looking for any results, but I would try and see if I notice a difference after making a change for other reasons.

My S2E fuel system which optionally has the installer physically remove the factory filter from inside the fuel pump module may help a little by increasing usable displacement inside the open lid surge canister that is integrated into the pump module. Not sure if its measurable either.

So basically we have to go dual pump or not turn right on the track? :confused:

Well... a standard dual pump wouldnt help but our road race pump solves it completely!

There are currently no real easy fixes for it. I have suggested trying some fuel cell foam tucked into the bridge across the fuel tank. It could possibly reduce sloshing a lot. Might have a side effect of making it annoying to fill the tank, but I doubt it. We will see if anyone ever tries it.

Or if you are return style already you could just put in a surge tank.

Edit: gives you a good excuse to put one of these fuckers in there SWEET BABY JEEZUZ

depends on how you feel about having a container of fuel pressurized to 50+psi inside the car. ive never been a fan, which is why I made the RRP. By putting it inside the fuel tank, it is able to function effectively without building up internal pressure. external surge cans which overflow to venturi's will inherently pressurize, for if they do not, the venturi's will not work, and you will fuel starve regardless of the surge can, as the surge can itself would be starved of fuel when the in-tank module isnt sending it anything.

In other applications, the run-of-the-mill external surge can like the radium is the go-to solution. In cars with return venturi's, theres a little more thought to put into it.

:confused: I'm failing to see what overflowing your tank on fill-up has to do with your gauge?? Did I read that wrong?:ugh2:

Which is why you could use a quality can like the radium one and not worry about putting it under 10-20 psi of pressure(at worst), then mount it up front or under the car, you also don't have to worry about getting 40-50 lacerations trying to run 10 feet of line across the inside of the factory tank and bending baffles out of the way by hand. Gas hurts like hell when you get it in a cut.

A 255lph in the factory unit with the regulator replaced with a straight through fitting, with a 90 degree bulkhead on the top to feed the venturii's with no regulator to restrict it and then do an easy return setup up front like ur stage 0 or just a set of rails with new lines, return and supply from the factory pump to the radium unit, and then from the radium's supply and regulator to the rails or line adapter. it isn't hard at all and like i said if your worried about it just mount it under the car or in the front like most external surge cans are anyway

Or if you are just a badass you could go with the cheaper TRIPLE surge tank, get an external regulator, a 340 in the factory pump to lift to the surge tank, and then you could even put a 190lph in one spot of the surge tank and route that back to the factory unit to specifically power the venturii's so the surge tank could have a non pressure dump return line into the top of the factory pump, and then you could have 2x 455lph e85 pump in the surge tank and feed your 2500hp badazz motor.

I personally dont want any pressurized container of fuel.

10-20 psi is not accurate. The return/venturi pressure in cars with upgraded fuel pumps is up to and over 50 psi.

For installing the RRP, there is just a couple of inches at the end of a baffle to bend. Big deal? If you are afraid of getting some little cuts on your hands, either cover the sharp edges, or dont work on cars.

I dont need a lesson from you on installing a generic surge can, its a practice that out-dates me. There are reasons you dont see them applied to these cars, ever... because the 350z crowd went through it, and its a delicate balance with its own inherit problems.

You can attack my product if you choose, by shedding tears over the installation... but it is far greater solution that has proven to eliminate the problem to the highest degree of success and has yet to show a single negative side effect or issue after installation :tup:

I am not trying to sell it anyway. If you want to do an external surge can in your 370z... be my guest... I will be here to take your calls to figure out how to solve all the problems with it like I do for the 350z guys that jump on it.

Coulda shoulda woulda! Build it and they will come.

I wasn't trying to teach you I'm just throwing it out there for others so we can have a few more options. After the drysump, manifold, exauhast, all poly mounts, suspension, radiator, oil lines and coolers, ati damper, wheels and tires, twin plate clutch and race hydraulics, and getting some body damage and a bit of interior fixed I'm going to be tapped out for mods for a good long while and this will be next on the list. Waiting to get the car's tune dialed in yet now after the 3" intakes and twin 70mm throttles, I've got an easy 15-20k in it and another 5k on the short list, and then fuel fix, and arms, and cage, and cams, and better headers, and retune again on e85, and upgrade the brakes again, and getting the race aero installed, it will be a year before I put together one of these for myself. The car is getting setup for max NA power on the factory bottom end, I don't want to say 400 but wen I got past 335 on a factory engine with a dry sump and exhaust we'll see what happens.

In a car with a build like that, I would probably consider handling an external surge can configuration as well. I just feel that the laundry list in your post with the 3 pumps in a surge can would actually work fine pending some details... but that its out of place in the average Z street car project. Its a layout description that displays you are able to think-around problems and solve it yourself, which is :tup:, I just think that by the time someone put that in a viable "kit" it would be equally or more expensive than the way I did it, and a bit more external race-car style clutter versus my efforts to contain it all within the fuel tank... which admittedly contributes to its own downsides of annoying installation and serviceability, a common attribute of street cars. :tup:

Yeah I am dying because I can't post pictures or details until the parts are ready for sale as it is all one-off prototype work at this time.

dailey engineering or a new dry sump?

new. Had to lose the ac for the pump. It's a traditional style with lines instead of being attached to the pan so i could always relocate it, but because there are lines i can get different pumps and add or delete stages in the future. right now its a 4 stage running 11in/Hg vacuum with all peterson gear and the new R4 pump which is supposed to have less hp draw than the daileys. 2.5 gallon oil capacity, wix racing oil filter, lightweight lines, all the good ****.

Edit: when it was first put on it was running 22in/hg until they turned down the regulator to 11in/hg, so I might run more vacuum in the future for a bit more power as well. Then when the slugs wear out go with light weight rods and pistons, with low tension rings and pull out another 5%

Also thats the last little teaser I'm posting don't want to get in trouble haha

Where does blowby go in a dry sump?

It gets sucked out with the oil, seperated in the tank, and vented through the vent can

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I don't understand going down to 2-4 dots. I would probably go crazy if I were a regular passenger of yours.

Then again, I'm also the person who pulls out after the first fill point. I shake my head at people sitting there clicking the trigger over and over to...do...what exactly? Pull out when you need to pull out. Refuel when you need to refuel. Life becomes much less stressful. :)