Fuel Lesson Learned

[HeyBales]

It seems the Hybrid & EB share the same external gas tank shell.

But how & why is the Hybrid’s tank pressurized? Are there internal pieces inside the hybrid tank taking up space? Also, is it negative or positive pressure?

It appears from the pictures of the tanks - they both benefit from having a hefty air space above the fuel inlet line.
And with full tank the level will rise above the inlet line.
That's an automatic block of fumes for awhile for the main tank.
The filler hose area would still have fumes - hence the canister being hooked to it.

I loaded the PIDs regarding fuel tank - there was a notice on the fuel level PID about EVAP leak check test ONLY runs between 30 -85% full.
Unlike other PIDs that state for hybrid or EB - this did not.
Makes sense - if fuel is blocking the inlet pipe, which is what the canister is connected to - can't check the whole tank. And too low, too much volume for the small pump to pull enough vacuum to confirm anything.

The why positive pressurized has been shown to reduce the amount of evap - which could become a problem with the ICE running less, therefore more time to evap.

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[dochawk]

Life was much simpler when we had mechanical fuel pumps.

Yes, nothing quite like vapor lock!

To that you served a bologna sandwich on a plate you kicked people in the leg with.

leaving aside how you kick someone with plate, I'd much rather be kicked in the leg than eat that foul psueudo-meat substance!

(fish lips and . . .)

 

[dochawk]

Actually that is a fair test too - to be at exactly half line - and does it actually refill to exactly half the stated gallons.

It's a ford fuel gauge--it's not meant to be taken literally1

(In fact, it refers to any manufacturers of dairy products!)

 

[Darryl]

Well, life may have been simpler back in those days, but it had little to do with fuel pumps. I've replaced two mechanical fuel pumps over the course of 54 years and zero electrical ones and most of those miles were on the electrical pumps. Of course they did have the benefit of modern technology.

Replacing mechanical fuel pumps were a regular repair back in the days when they were common. If you had a 1970s era car , eventually you were probably going to have to replace the fuel pump at least once, maybe twice by the time you reached 100,000 miles. Today with the complicated electric fuel pumps, it's not unusual to go the entire life of the vehicle with the original fuel pump.

 

[Automan21]

I’ve gone to the 5 mile warning.

 

[Meeka]

Yes, nothing quite like vapor lock!





leaving aside how you kick someone with plate, I'd much rather be kicked in the leg than eat that foul psueudo-meat substance!

(fish lips and . . .)

Baloney and Spam, the best,

 

[Darryl]

I’ve gone to the 5 mile warning.

You haven't lived life on the edge until you've driven a few miles with the 0 to empty light on at least once

 

[dochawk]

If you had a 1970s era car ,

I'm not even clear on why I had to remove & reinstall the fuel pump on my '72 Cadillac--probably because it was necessary to get to something for the water pump replacement.

Anyway, I found that it isn't even possible to remove both bolts with the same tool--one requires some inches of extension, while the other I don't think even had room for a socket wrench!

(oh, and as it turns out, you don't need to remove both--one merely needs to be loosened, and it can slide off once the other is removed; it's a U on that side.)

Once it's fully running, at the very first sign of vapor lock I will be adding a switched electric pump!

Oh, and odd bit: the 472/500 Caddy V8 has a second fuel filter in that pump. It takes a rather large socket (1-1/4?) to remove it. It seems to fit the same filter as the one just before the carb.

 

[Darryl]

I'm not even clear on why I had to remove & reinstall the fuel pump on my '72 Cadillac--probably because it was necessary to get to something for the water pump replacement.

Anyway, I found that it isn't even possible to remove both bolts with the same tool--one requires some inches of extension, while the other I don't think even had room for a socket wrench!

(oh, and as it turns out, you don't need to remove both--one merely needs to be loosened, and it can slide off once the other is removed; it's a U on that side.)

Once it's fully running, at the very first sign of vapor lock I will be adding a switched electric pump!

Oh, and odd bit: the 472/500 Caddy V8 has a second fuel filter in that pump. It takes a rather large socket (1-1/4?) to remove it. It seems to fit the same filter as the one just before the carb.

I do remember the various fuel pumps and how some of them were fairly easy while other were fairly difficult. Others such as the small block Chevy weren't that difficult, . You just had to know the "trick". But replacing fuel pumps was something every mechanic knew how to do. I think I recall the pump on the old caddy's being somewhat of a pain.

 

[dochawk]

Baloney and Spam, the best,

By my childhood, Spam was merely a novelty; something exotic for housewives to experiment with.

For two generations before . . .

Audrey Murphy, the most decorated soldier of WWII and later an actor, was invited to a dinner, in his hometown, iirc.

His hostess served a casserole of which she was quite proud.

He shuddered and politely declined, saying that he couldn't eat it--spam is C-ration! He'd had more than his lifetime dose by that time.

 

[Darryl]

Good point about the ACCS. Although there could be multiple culprits - some “guiltier” than others.

I always believe in grabbing the low hanging fruit. We've had 4 come in with the problem. Reprogramming the air Conditioning Control Module (ACCM) fixed 3 of the 4. That's pretty good odds

 

[HeyBales]

It appears from the pictures of the tanks - they both benefit from having a hefty air space above the fuel inlet line.
And with full tank the level will rise above the inlet line.
That's an automatic block of fumes for awhile for the main tank.
The filler hose area would still have fumes - hence the canister being hooked to it.

I loaded the PIDs regarding fuel tank - there was a notice on the fuel level PID about EVAP leak check test ONLY runs between 30 -85% full.
Unlike other PIDs that state for hybrid or EB - this did not.
Makes sense - if fuel is blocking the inlet pipe, which is what the canister is connected to - can't check the whole tank. And too low, too much volume for the small pump to pull enough vacuum to confirm anything.

The why positive pressurized has been shown to reduce the amount of evap - which could become a problem with the ICE running less, therefore more time to evap.

Ok - just hit 0 miles to empty leaving grocery store last night, next stop got a picture if the values for 2 PIDs.
Been observing those 2 since just past last fillup. (so couldn't confirm 100% start)

The Accelerometer PIDs show I wasn't exactly level at picture time, slight tilt to right and nose up - so away from the fuel pump area of tank, which is front left bottom.

FLI - Fuel Level Indicator, has been pretty much matching the fuel gauge drop at 75%, 50%, 25%. Not exactly, so it's not the gauge reading, but must be used for it.

FUELLEVEL - on the other hand, I'm guessing is related to a % of the fuel tank vertical space left, literally.
It was never at 75% or above when I added the PIDs, dropped faster than FLI until abouts 30%, then seemed to drop very slow as FLI went lower - then it caught up, and went lower.
So I'm guessing it's what % of a rod float reading scale the level is at - not sure where it would be located.

2.35% of 16.5 gal useable gal tank = 0.39 gal - even that doesn't seem right and way too low.
Maybe that's the level starting at minimum required for fuel pump. As Mavster Mechanic said in his test of running out - it just stopped, no sputtering last few drops, and started right up on fill-up as no air in line.
My guess if I kept going - it would drop very slowly.

FLI 5.88% of 13.8 used in math = 0.8 gal - that sounds better as built-in reserve when it's declared 0 miles left.
So even if someone doesn't want to believe about the extra 2 gal really there - you have plenty of miles left to get to station.

So pay attention to the highway sign stating "180 miles to next fuel stop", but don't rearrange your errands or get questionable gas because you think you have 0 miles.

(unrelated - TFT - tranny temp is held better after a grocery store stop @ 28F than INT_TEMP of DCDC Convertor)

ETA: just filled up level ground - normal 2nd click (done in case the 1st clicked very early, which happens).
FLI maxed at 96.xx%. Needle was top of full line.
Going down slight hill later - read 100%, didn't go over when it probably could have.
The reading does change quickly as tilt happens, so slosh. The gauge must use this, but smooth it out for display.
FuelLevel - only went to 39% - so it must mean something else, or values being read wrong.

 

[Darryl]

For what it's worth note: The ability of an owner to access a lot of information is both a blessing and a curse. Blessing: When there is a problem, having the benefit of the customer given information is often very valuable and can often help us with diagnosis of intermittent problems.
Curse: when the customer overanalyzes information and stresses about things that are no problem . Example A customer stresses because he thinks the fluid in his transmission is going to degrade because the temp is 220. But he doesn't realize the the ULV fluid is DESIGNED for high temp. Example. Although the Ford 10 speed is a totally different transmission, it uses the SAME fluid as the 8F35. And Ford tells us to CHECK the fluid level between 206 and 215 degrees. Even though the Maverick says to check at a lower temp between 185 and 200. It's obvious the fluid can stand a higher temp. Another example is tire pressure. We have customers obsessing because one tire is 2 psi lower than the others per their scan tool or instrument cluster readings not realizing that the tpms sensors are NOT exact. Information is only as good as knowing how to analyze it. Before saying something is too hot, too high, it too low. A person would do best to find out the manufacturer expected readings and the readings that they consider cause for concern.
Information is power. But information can also be nerve wracking

 

[Meeka]

For what it's worth note: The ability of an owner to access a lot of information is both a blessing and a curse. Blessing: When there is a problem, having the benefit of the customer given information is often very valuable and can often help us with diagnosis of intermittent problems.
Curse: when the customer overanalyzes information and stresses about things that are no problem . Example A customer stresses because he thinks the fluid in his transmission is going to degrade because the temp is 220. But he doesn't realize the the ULV fluid is DESIGNED for high temp. Example. Although the Ford 10 speed is a totally different transmission, it uses the SAME fluid as the 8F35. And Ford tells us to CHECK the fluid level between 206 and 215 degrees. Even though the Maverick says to check at a lower temp between 185 and 200. It's obvious the fluid can stand a higher temp. Another example is tire pressure. We have customers obsessing because one tire is 2 psi lower than the others per their scan tool or instrument cluster readings not realizing that the tpms sensors are NOT exact. Information is only as good as knowing how to analyze it. Before saying something is too hot, too high, it too low. A person would do best to find out the manufacturer expected readings and the readings that they consider cause for concern.
Information is power. But information can also be nerve wracking

Awesome Darryl! Hope many others read this instead of just glancing over it, (like I usually do)

 

[Darryl]

Awesome Darryl! Hope many others read this instead of just glancing over it, (like I usually do)

I don't blame you. I know that I sometimes write too much like I'm writing a documentary. So it's easy to skip over. But I see i am not alone.

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