[BDCCruze]

How are you putting 18 gallons in? Mine clicks off at about 14.5. I can maybe squeeze in another .5 gallons till it at the neck. I've had the low fuel light on and put 50 more miles on before getting gas and it still barely makes it over 15.

 

[Rivergoer]

How are you putting 18 gallons in? Mine clicks off at about 14.5. I can maybe squeeze in another .5 gallons till it at the neck. I've had the low fuel light on and put 50 more miles on before getting gas and it still barely makes it over 15.

If you have a Gen 1 CTD, the tank WILL hold over 18 gallons...you just need to be very patient.

When diesel fuel comes out of the pump it foams. That foam creeps up the fill pipe and clicks off the pump.

To truly “top off” your tank to the very end of the fill pipe, you have to keep clicking the pump on very slowly till the foam reaches the top, stop for 10-15 seconds and repeat. This process will go on for about 10 minutes.

Eventually the diesel level will reach the top of the fill pipe and you will visibly see diesel (not foam) level with the fill pipe opening.

My experience has been that the point at which diesel fuel pumps click off varies from station to station. But generally after the pump clicks off on the Gen 1 CTD, you can get another 2-3 gallons into the tank/fill pipe.

That can equate to another 100-150 miles of range on a filler-up!

(added note: 18+ gallons would be achieved only after running the tank down about 60-80 miles PAST the Low Fuel light)

 

[BDCCruze]

This guy says covering the vent hole on the fuel nozzle eliminates foaming. I think that's the hole that also tells it when to click off so you have to be careful. In their forums he said if you just do about 1/2 flow you can cover the hole without stopping it from clicking off.

https://www.youtube.com/watch?v=AB082zQ7Das

 

[DslGate]

This guy says covering the vent hole on the fuel nozzle eliminates foaming. I think that's the hole that also tells it when to click off so you have to be careful. In their forums he said if you just do about 1/2 flow you can cover the hole without stopping it from clicking off.

https://www.youtube.com/watch?v=AB082zQ7Das

You're going to have to wear plastic gloves on that one ( if you don't want smelly hands , that is)....I carry a box of the nurses-type gloves in the car. Cheap at Costco or SAMs.

 

[BDCCruze]

You're going to have to wear plastic gloves on that one ( if you don't want smelly hands , that is)....I carry a box of the nurses-type gloves in the car. Cheap at Costco or SAMs.

The place I fill up has plastic gloves out by the diesel pump, thankfully. I thought I read somewhere that overfilling the tank will cause damage. I wonder if the foaming is considered when they are planning tank capacity and sending unit design.

 

[Rivergoer]

The place I fill up has plastic gloves out by the diesel pump, thankfully. I thought I read somewhere that overfilling the tank will cause damage. I wonder if the foaming is considered when they are planning tank capacity and sending unit design.

Yeah I tried that “cover-the-hole” technique a few months ago, didn’t work for me at all...made no difference with the foaming.

I’ve been topping my diesel to the rim for a year with no adverse effects whatsoever. My understanding is this should NOT be done with gasoline vehicles but OK for diesels.

 

[BDCCruze]

Yeah I tried that “cover-the-hole” technique a few months ago, didn’t work for me at all...made no difference with the foaming.

I’ve been topping my diesel to the rim for a year with no adverse effects whatsoever. My understanding is this should NOT be done with gasoline vehicles but OK for diesels.

Hmm interesting, know what the difference is?

I've replaced the sending unit on more than one gas vehicle and it always seems everything is always submerged anyways. Maybe it has to do with the evap system? Not sure how different that would be on a diesel. Interesting though.

 

[TX CTD]

Gasoline expands when it warms up so there need to some room in the tank for that. Diesel doesn't so it won't hurt to fill it all the way to the top.

 

[Rivergoer]

I might add with my driving pattern, I always top off and jump on the highway for a 200+ mile cruise so the fuel doesn’t sit (topped off) for any length of time.

 

[Cruzator]

I was curious if anybody has had their tank out (or filler tube off the tank). I know a lot of the gasoline tanks on cars have a float, that covers the inlet to the tank once they are full. This helps prevent overfilling, and also prevents the gas from coming out in case of a roll over. I'm guessing the diesel Cruze might have this as well. That (in addition to foaming) may be why it takes so long to fill it to the brims, as the fuel has to seep by the float (or check valve). Just curious.

 

[kdsmalljr]

Did you post these changes in the forum or technical section? Did you try the OZ Tune. Can't decide between OZ and CHIP Express: https://www.chipexpress.com/

It has a few enhancements plus a few mods.

Tire pressures are maxed out, 55-58 psi warm.

Grill block off ran below 65°f

Partial extended belly pan between rear axle and rear bumper

Amsoil full synthetic fluids throughout power train

Pretty rowdy tune in computer

Removed extra parts and pieces to reduce weight


Sent from AutoGuide.com Free App

 

[froyofanatic]

If you have a Gen 1 CTD, the tank WILL hold over 18 gallons...you just need to be very patient.

When diesel fuel comes out of the pump it foams. That foam creeps up the fill pipe and clicks off the pump.

To truly “top off” your tank to the very end of the fill pipe, you have to keep clicking the pump on very slowly till the foam reaches the top, stop for 10-15 seconds and repeat. This process will go on for about 10 minutes.

Eventually the diesel level will reach the top of the fill pipe and you will visibly see diesel (not foam) level with the fill pipe opening.

My experience has been that the point at which diesel fuel pumps click off varies from station to station. But generally after the pump clicks off on the Gen 1 CTD, you can get another 2-3 gallons into the tank/fill pipe.

That can equate to another 100-150 miles of range on a filler-up!

(added note: 18+ gallons would be achieved only after running the tank down about 60-80 miles PAST the Low Fuel light)

It sounds like you might be filling the vapor space.

 

[sailurman]

It sounds like you might be filling the vapor space.

That's what she said.....

 

[BDCCruze]

It sounds like you might be filling the vapor space.

Yes, that is what is happening. Running the tank that high can damage the evap system. However, it is possible that due to the nature of diesel foaming that GM built the tank to allow fuel to run up over the evap valve and not cause issues.

But for those that want to do this, I would imagine putting 3 gallons of fuel into a fuel jug before filling your car, then use the fuel jug to top off since it won't be foamy once the handle clicks off. That may be an easier way to get it completely full rather than clicking it off for 10 minutes. Or you could just drive home and finish filling up so that people don't stand there wondering what that weirdo at the pump is doing :laugh:

 

[Rivergoer]

Just missed another 1,000 mile tank by 35 miles.

Topped off at 17.7 gallons so 1,000 was definitely doable. Low Fuel light illuminated at 906 miles.

Started in Phoenix, AZ, drove to Anaheim, CA then through Las Vegas, NV, St. George, UT and ended up at Page, AZ (Lake Powell). Pretty amazing car.

 

[BU54]

You're taking pics while driving??? lol

 

[Rivergoer]

Chalk up another 1,000 mile tank. 1005 miles to be exact on 18.275 gallons. Hand calc @ 56 mpg. (Pics show how BCM/ECM calcs have been a bit off since a few parts ‘fell off’)

 

[BDCCruze]

Are there any known, documented, and provable reason for a decline in fuel economy? This summer, after a few months of watching, I'm down about 1 MPG average over a full tank.

 

[Rivergoer]

Weather seems to have a lot to do with my fuel economy. Heat and wind can really impact mpg.

I regularly run I-10 between Arizona and California. From about May to October the prevailing winds out of the West can cost me 3-4 mpg heading into CA. On the return trip to AZ if I catch a tailwind it can cancel out most of that loss but not always all.

Then there are those trips where I fight headwinds both ways. Depending on time of day the winds can switch from West to East.

Add to that it’s HOT (less-dense air = decreased efficiency). The turbo helps to negate this impact but it’s still noticeable.

Winter to Spring the winds die off for the most part. It’s on those calm, cool days where the car is most efficient.

 

[MP81]

Hot weather actually should be pretty good for fuel economy - less dense air doesn't mean anything for efficiency, it just means less power, since less air = less fuel needed = less power. But less fuel = more fuel efficient. But if it's too hot, now the AC is on, and you're putting a load on the engine.

It's why a short-ram intake should actually improve fuel economy at the expense of power (despite what they claim - probably because their dyno tests are done with an open hood).