My fuel pump went out

[kb0nly]

I'm a 1/4 tanker here also... I very rarely run any vehicle below that mark. Just learned that over the years its best to keep it at 1/4 or above to make sure the pump and such is submerged and being kept cool. And in the winter i hardly ever let it go below 1/2 and prefer to keep it full, less frost buildup in the tank. Not as a big of a problem on modern vehicles but old habits die hard. Have frozen fuel lines once and you will get that habit too.

 

[belvedere]

I'm a 1/4 tanker here also... I very rarely run any vehicle below that mark. Just learned that over the years its best to keep it at 1/4 or above to make sure the pump and such is submerged and being kept cool. And in the winter i hardly ever let it go below 1/2 and prefer to keep it full, less frost buildup in the tank. Not as a big of a problem on modern vehicles but old habits die hard. Have frozen fuel lines once and you will get that habit too.

Exactly what I do. Must be because we live in the same climate!

 

[belvedere]

Going under a 1/4 tank will shorten the fuel pump life.Even though the KJ's fuel filter is a so called "lifetime" filter it is not and should be changed often as a fuel filter that is as little as 15% plugged will increase the fuel pump amp draw by 100% and reduce fuel flow at the injectors by 200% which also kills fuel pumps.

Do you have a reference for these numbers? To reduce fuel flow (or anything, for that matter) by 100% would bring it to zero. So, to reduce flow by 200% would mean that fuel is flowing in the reverse direction.

 

[tjkj2002]

Do you have a reference for these numbers? To reduce fuel flow (or anything, for that matter) by 100% would bring it to zero. So, to reduce flow by 200% would mean that fuel is flowing in the reverse direction.

Total flow and what is needed are 2 different things,some vehicles you can reduce the flow by about 500% before noticeable(to normal idiots)driveability issues will occur.Go to some advance diagnostic classes and you will get all the info you want about driveability issues that deal with dirty fuel filters.

 

[belvedere]

I don't think you're understanding me. If you reduce anything by 100%, you're down to zero. That could be your bank account balance, your gas tank level, or your fuel flow. If you have $100 in your account, reduce it by 100%, and you're at zero. So, reduce it by 200%, and you're $100 in the hole. So when you "reduce fuel flow by 200% (or 500%)", your fuel is flowing back into the tank from the engine! Great for fuel economy, not too practical in the real world!

That's why your numbers are not credible. Can you provide a reference for your information, something we can look?

 

[belvedere]

Believe me - I agree that a partially clogged fuel filter will cause an increased amp draw from your pump, and that it sure doesn't do your pump any good. I'm just saying that it makes you alot more credible if your supporting numbers are actually realistic.

 

[tjkj2002]

I don't think you're understanding me. If you reduce anything by 100%, you're down to zero. That could be your bank account balance, your gas tank level, or your fuel flow. If you have $100 in your account, reduce it by 100%, and you're at zero. So, reduce it by 200%, and you're $100 in the hole. So when you "reduce fuel flow by 200% (or 500%)", your fuel is flowing back into the tank from the engine! Great for fuel economy, not too practical in the real world!

That's why your numbers are not credible. Can you provide a reference for your information, something we can look?

Your not thinking like a tech.They over engineer the fuel systems nowdays(hard lessons learned in the '90's).So let's say your injectors need a min of 150ml per min for the best operation so they make the pump able to deliver 300ml per min capacity with a clean filter(just #'s thrown out there).So the total flow is 200% of what is needed and if you reduce it by 100% your left with 100%,you know simple math like 200-100=100.

Get it now?

(doubt it but worth a shot)

 

[Porkchop]

Tjkj think if thay buy a 150% or prof bottle of Don-Q rum it has more than the bottle can hold?

 

[jnaut]

Your not thinking like a tech.They over engineer the fuel systems nowdays(hard lessons learned in the '90's).So let's say your injectors need a min of 150ml per min for the best operation so they make the pump able to deliver 300ml per min capacity with a clean filter(just #'s thrown out there).So the total flow is 200% of what is needed and if you reduce it by 100% your left with 100%,you know simple math like 200-100=100.

Get it now?

(doubt it but worth a shot)

As an engineer and a tech, this represents poor terminology. The way to describe this then would be "a reduction of flow below baseline".

When speaking generically about "flow", corking the system and stopping the flow is a "100% reduction of flow". But if what you mean is flow is running above baseline or 'normal' then you have to describe flow loss relative to the baseline. Because even if flow is 1,000,000x (putting pinkie to corner of mouth) above baseline, and you stop the flow, you have still reduced flow by 100%.

More specifically, if the system requires 150ml per min, but is getting 300ml per min, then reducing flow to 150ml would be a 50% reduction of the flow. Or one could say a 100% of the above-baseline flow. But from a point of clarity, this muddies things up.

 

[belvedere]

Thank you, jnaut. My explanations are obviously not working.

 

[belvedere]

Your not thinking like a tech.

LOL! Now the basic rules of math change, depending on your job title. ](*,)

 

[kb0nly]

As an engineer and a tech, this represents poor terminology. The way to describe this then would be "a reduction of flow below baseline".

When speaking generically about "flow", corking the system and stopping the flow is a "100% reduction of flow". But if what you mean is flow is running above baseline or 'normal' then you have to describe flow loss relative to the baseline. Because even if flow is 1,000,000x (putting pinkie to corner of mouth) above baseline, and you stop the flow, you have still reduced flow by 100%.

More specifically, if the system requires 150ml per min, but is getting 300ml per min, then reducing flow to 150ml would be a 50% reduction of the flow. Or one could say a 100% of the above-baseline flow. But from a point of clarity, this muddies things up.

=D> Good Explanation!

 

[tjkj2002]

LOL! Now the basic rules of math change, depending on your job title. ](*,)

Nope,like stated just look in the pic below and the following description,guess you didn't think there are 6 injectors in our engine(just a basic injector rail pic,not a KJ's but same principle).

You must be registered for see images attach

Now 500ml of flow is coming in at the inlet,each injector requires 150ml flow for nominal operation.Notice where the inlet is?

After 2(or 3) injectors fire there is a lag time for the pump to return the flow rate(milli seconds) so the #3 injector is going to get short changed from the natural parasitic draw from the other 5.With a partially plugged filter that #3 injector could be receiving little to no flow(severely plugged filter).If you could look at the fuel trims(short term and long term) you could see this taking place even with a brand new fuel filter on a "V" engine,the fuel trims will always be closer to zero on the fuel inlet side of the engine,get's worse as the filter starts to plug up.


Sorry if my explanation was not clear enough.


A good example of this was the mid '90's Chrysler 5.2/5.9.It was a common issue when it would have the 2 rear most passenger side cylinders misfire and lack of power.They had a partially plugged fuel filter and why the started over-designing the fuel systems so the interval for changing the filters could be increased(but still should not be).

 

[belvedere]

Ok, I give. As I previously stated, I was not disputing the fact that a plugged filter reduces flow or increases pump draw. No advanced diagnostic classes needed. I was simply stating that you can't have over a 100% reduction in flow, or you would be flowing in the opposite direction! IOW, fuel flowing back to the tank. Jnaut tried to explain it to you, too. It's just not mathematically possible, and math is the same whether you're a carpenter, an auto tech, or a NASA engineer. Please read what people type before you answer.

 

[tjkj2002]

Ok, I give. As I previously stated, I was not disputing the fact that a plugged filter reduces flow or increases pump draw. No advanced diagnostic classes needed. I was simply stating that you can't have over a 100% reduction in flow, or you would be flowing in the opposite direction! IOW, fuel flowing back to the tank. Jnaut tried to explain it to you, too. It's just not mathematically possible, and math is the same whether you're a carpenter, an auto tech, or a NASA engineer. Please read what people type before you answer.

Most newer FI use a returnless system(another part of a over built fuel system to help combat driveability issue).Again look at the pic and were the inlet is,the last in the line injector will receive little to no flow with a partly plugged filter,that's physics and the math can not be denied by even your standards,#3 injector(in pic above) can get ZERO flow when #5 and #6 are getting just barely enough.

 

[belvedere]

](*,)

 

[tjkj2002]

](*,)

Do that enough and you may see the light.

 

[Prospect62]

Some people are never wrong even when they're wrong. I know the type well (and I don't particularly care for the type). Nothing you can do but agree with them, unless you like perpetual d**k measuring contests.

 

[belvedere]

Of course you're right, Prospect. I just like to help people (as do most folks on this forum), and get in the mindset that if I point something out to someone, they will be receptive to it and want to learn. That's how I am, anyway, I like to learn new things. I just have to remember that not everyone is the same.