Diesel Place banner

1 - 9 of 9 Posts

·
Registered
Joined
·
99 Posts
Discussion Starter #1
This a 1999 6.5TD Suburban 2500 4WD.

There is a large amount of air getting to the fuel filter housing.

Here's the scoop:

The suburban just came back from a 2500 mile trip without missing a beat.
Prior to the trip the fuel filter was changed, the lift pump changed with new orings and the lift pump relay replaced. The PMD and OPS were also
replaced with good units and just checked again.

The lift pump produces 9 to 11 psi at the filter drain valve.

I installed indicator lights and toggle switch to watch the ops and lift
pump relay and they are working fine.

There are no visable leaks in the fuel lines.

I have rechecked the lift pump orings and it is tightened.

I can blead the air out of the filter housing but it returns and causes a
skip and loss of power to the point it almost stalls.

Is there a connection in the tank that can come apart and let air in the
fuel system ? What am I missing here ?

Other than this problem it runs like a bear.
 

·
Registered
Joined
·
43 Posts
TDHDIESEL;1313591; said:
This a 1999 6.5TD Suburban 2500 4WD.

There is a large amount of air getting to the fuel filter housing.

Here's the scoop:

The suburban just came back from a 2500 mile trip without missing a beat.
Prior to the trip the fuel filter was changed, the lift pump changed with new orings and the lift pump relay replaced. The PMD and OPS were also
replaced with good units and just checked again.

The lift pump produces 9 to 11 psi at the filter drain valve.

I installed indicator lights and toggle switch to watch the ops and lift
pump relay and they are working fine.

There are no visable leaks in the fuel lines.

I have rechecked the lift pump orings and it is tightened.

I can blead the air out of the filter housing but it returns and causes a
skip and loss of power to the point it almost stalls.

Is there a connection in the tank that can come apart and let air in the
fuel system ? What am I missing here ?

Other than this problem it runs like a bear.
I had the same problem. The sending unit on the fuel tank was sucking air. There was a small amount of rust around the down tube. BTW, I had just replaced my lift pump also thinking I had a problem there.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #3
borus,

Ok, was the leak fixable with out totally replacing the tube assy going into
the tank or should I order a new assy ?
If you did a fix please let me know the method you tried.

Sounds like I got my work cut out for me since the tank has 45 gallons in it.

Thanks for the help,
 

·
Registered
Joined
·
43 Posts
I had ran out of options and decided to drop the tank to check the sender. Discovered the small amount of rust around the down tub and the sender brace plate. I was told from a diesel mechanic that it had been a source of problems in the past on other trucks. I would replaced the entire sender as I think it was just over $100. I didn't want to try and fix it. It did give me peace of mind that I addressed most of my fuel issues. I have replaced my ip in the past (20K) ago. Hope this helps...
 

·
Registered
Joined
·
99 Posts
Discussion Starter #5
Boris,
Thanks for the info.
Just an update.
I replaced the fuel lines , the fuel tank (really rusted from dirt and salt
between the tank and plastic stone shield) and the fuel sending unit
assembly.
After pricing around the cheapest I could find the sending unit was about
$250 with tax and shipping from NAPA , $190 plus tax for the tank and about
$100 for fuel injection line, clamps, filters, etc .
Not the cheapest fix but it runs way better than the past few months.
I did find 3 pin holes in the sending unit . That is why no leaks were visable,
since they were above the fuel level and under suction from the lift pump.
Thanks again for your help.
 

·
Registered
Joined
·
43 Posts
Glad to be able to help
 

·
Registered
Joined
·
689 Posts
Borus,

What's involved in dropping the tank and inspecting the sending unit. Is this also where the sock is located or is that still lost in the dryer...no, seriously.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #8
Hey Dan,

I am not sure if you drive a pickup or a suburban, but nice boat
The tank removal is still clear in my mind if you need a play by play
description to help.

The sock in my burb looked just like new when I pulled it out of the tank.
To bad every thing else out side of the tank did not look as good.
 
  • Like
Reactions: jimclemjr

·
Premium Member
Joined
·
8,462 Posts
Hey Dan, while you have the tank out. Buy some POR and paint the tank. It will keep it from rusting again. Dont paint the sending unit, use a rubberized undercoating for the top of the sending unit.
 
1 - 9 of 9 Posts
Top