The Gear Box

Welcome to the Gear Box!  Please use the message boards for technical questions.


 

joanfenn

2020 Nov 26 13:40:46
Wow hello Fredric, nice to see you again. Happy thanksgiving to you
 

Stripe

2020 Nov 26 12:51:53
Happy Thanksgiving!
 

ClydesdaleKevin

2020 Nov 26 12:26:33
Happy Thanksgiving everyone!!!
 

Oz

2020 Nov 25 01:26:28
Thank you Joan!
 

joanfenn

2020 Nov 25 00:42:41
Have a good and safe one Mark.  We already had ours last month but will be with you in spirit.  And drooling also. 
 

Oz

2020 Nov 24 16:29:55
Happy Thanksgiving everyone!
 

Elandan2

2020 Nov 22 13:31:55
Ah, that's better. Thanks for all the great improvements Mark. :)ThmbUp
 

Oz

2020 Nov 22 05:15:11
You're welcome!
 

TerryH

2020 Nov 22 03:48:06
Yes - seems to be up and running. Missed it while gone. Thanks Mark!
 

Oz

2020 Nov 17 03:32:58
I know, right?  The changes to the site are coming along, but not without its glitches, of course.  Always a learning curve...
 

joanfenn

2020 Nov 16 18:01:10
This one is good also.  Just nice to chat again
 

Oz

2020 Nov 15 13:09:30
 :D
 

joanfenn

2020 Nov 15 02:49:50
I am used to this one, but not to old enough to learn
 

Oz

2020 Nov 15 02:36:28
Do you like this way better, or the balloon box version?
 

Oz

2020 Nov 14 23:02:46
Thank you!   :)clap
 

Oz

2020 Nov 14 23:01:19
Not as compact with the text, but maybe a bit more "fun" and "chatty"?
 

joanfenn

2020 Nov 14 23:01:18
carry on sir, you are doing a great job :)ThmbUp
 

Oz

2020 Nov 14 23:00:29
LOl!  :D
 

joanfenn

2020 Nov 14 22:58:41
yes it is growing on me now :)
 

Oz

2020 Nov 14 22:58:06
I kinda like it.
 

joanfenn

2020 Nov 14 22:57:57
And I wasn't going to say anything but your are special, not odd
 

joanfenn

2020 Nov 14 22:56:46
It will work just have to get used to the layout
 

Oz

2020 Nov 14 22:55:53
Well, I'm odd.  So... yeah, kinda fits just right.
 

joanfenn

2020 Nov 14 22:55:47
Funny layout I mean.  But nice to be able to chat again
 

Oz

2020 Nov 14 22:55:24
Just transitioned to the new portal system.  I have a lot to recreate yet, but it won't take long. How do you like the new chat room?
 

joanfenn

2020 Nov 14 22:54:24
This is odd
 

Oz

2020 Nov 14 22:53:50
Hi Joan!
 

joanfenn

2020 Nov 14 22:52:54
Hello!!

Author Topic: 1990 Winnebago Superchief (Chevy P30) -- Fuel Sending Unit -- 80 gallon tank  (Read 248 times)

0 Members and 1 Guest are viewing this topic.

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Last week I diagnosed that our fuel pump was not working correctly, by borrowing a fuel pressure gauge from O'Reilly Auto Parts.  Pressure maxed out at 2 PSI (instead of 13) and dropped off immediately.  After dropping the tank using 4 ratchet straps, and pulling the fuel sending unit out, I found there was a slit in the small flexible tube between the pump and the metal tube that goes up and out of the tank.  I could easily replace the small tube, and the pump itself (which is a GM E3902), but I would prefer to replace the entire fuel sending unit while it is out and everything is torn apart.  The main reason is that the fuel gauge on the dash is not working, and I suspect the sensor on the sending unit is toast.

None of the national parts stores have matching sender units because I have an 80 gallon tank.  It has a depth of 16".  All of the units they have ordered have been about 2" shorter than the existing one.  This would put the pump at about the level of the generator supply nipple on the side of the tank, which risks the motorhome running out of gas before the generator.

Searching all over the internet I cannot find any sending units for a 80 gallon tank (16" deep).  They are all for 40 gallon tanks and explicitly say not for 80gal or for buses.  I also cannot find an exact part number for the existing unit.  The Winnebago parts manual PDF is unreadable for the sender unit.  It appears to be 086254-01-000 or 096254-01-000.  Cannot find any cross references for those part numbers though.

Has anyone replaced their fuel sending unit on a Chevy P30 chassis with an 80 gallon tank?  If so, where did you find a replacement and what was the part number?
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Oz

  • Top Post Contributor
  • *
  • Posts: 3551
  • Member since: 2002
  • I own: a Motor Home
  • Year: 1974
  • Make: Winnebago
  • Model: D24 Indian
  • Chassis: Dodge
  • Engine: 440-3
I was looking all over for one as well, ran into same thing, "except 80 gallon".
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Hi Oz,

For 40 gallon tanks this is what I have found:

    * Spectra Premium FG12S and D12S1H
    * ACDelco FLS1066

Can't guarantee these would actually work, but they look exactly the same as mine, just shorter.
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline tmsnyder

  • Top Post Contributor
  • *
  • Posts: 668
  • Member since: 2016
  • I own: a Motor Home
  • Year: 1976
  • Make: GMC Motorhome
  • Model: Eleganza II
  • Chassis: GMC
  • Engine: 455
You can also use the available sending unit, as long as it has the same ohm range to match your dash gauge and as long as it fits the top of the tank and seals, and you can modify the part of the sending unit inside the tank to work.    In your case you might have to extend the dip tube with steal tubing of the same diameter using either a compression union or brazing union.   The wires can be extended as well if needed, soldered and shrink wrapped.   And the level sender can be modified so that the full sweep of motion is from empty to full.  I had to do this on my GMC b/c the ones available were about 10x more money than a common full size chevy car sending unit. 
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Oz

  • Top Post Contributor
  • *
  • Posts: 3551
  • Member since: 2002
  • I own: a Motor Home
  • Year: 1974
  • Make: Winnebago
  • Model: D24 Indian
  • Chassis: Dodge
  • Engine: 440-3
Yeah, that seems to be the big issue.
They fit but they're not long enough.
It may indeed require modifying a shorter one if one for an 80 gal tank can't be found.
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
@ tmsnyder, that is a good idea that I had not thought of.  Thank you.
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Ericb760

  • Post Contributor
  • *
  • Posts: 104
  • Member since: 2019
  • I own: a Motor Home
  • Year: 1989
  • Make: Winnebago
  • Model: Chieftain 28
  • Chassis: Chevy
  • Engine: 454
I  have the same problem with my 89' Chieftain, only with the 40 gallon tank. Can you please explain exactly how you dropped the tank using ratchet straps? This seems like a much better option than jacking the tank completely out. Thanks, Eric
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions
1989 Winnie Chieftain 28'

Offline Oz

  • Top Post Contributor
  • *
  • Posts: 3551
  • Member since: 2002
  • I own: a Motor Home
  • Year: 1974
  • Make: Winnebago
  • Model: D24 Indian
  • Chassis: Dodge
  • Engine: 440-3
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Ericb760

  • Post Contributor
  • *
  • Posts: 104
  • Member since: 2019
  • I own: a Motor Home
  • Year: 1989
  • Make: Winnebago
  • Model: Chieftain 28
  • Chassis: Chevy
  • Engine: 454
Informative thread. I remember reading that when I first joined but it didn't sink in because I didn't need it then...
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions
1989 Winnie Chieftain 28'

Offline Oz

  • Top Post Contributor
  • *
  • Posts: 3551
  • Member since: 2002
  • I own: a Motor Home
  • Year: 1974
  • Make: Winnebago
  • Model: D24 Indian
  • Chassis: Dodge
  • Engine: 440-3
Which is why our forum is a great resource. What we may not need now will still be there, and able to find, down the road when we do!
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Hi @Ericb760, I put 4 ratchet straps under the belly of the tank and attached the hooks in the closest holes or crevices I could find for each.  After cinching them all up tight, I removed the bolts at the front and back of the tank (4 total).  Then removed nuts holding the 3 metal straps that help hold the tank in place.  One of the straps has its bolts way up inside of the HWH leveling jacks.  One bolt was completely unreachable, but I was just barely able to get to the other using a swivel attachment on the end of the impact wrench.  Once that bolt was off it was possible to swing the remaining metal strap out of the way rotating around its other bolt.

It was then just a matter of patience to let each of the ratchet straps out an inch at a time, slowly bumping the tank down.  One gotcha, the metal flange on the front of the tank got caught on the air ride suspension leveling sensor boxes.  It bent one of the boxes down a bit before I realized it.  Had to draw the tank back up a bit, and then man handle it a few inches toward the back so it would clear when dropped.  Overall the process worked really well, even with about 30 gallons still in the tank.  If I had to do it again, I would recommend lowering the back of the tank a bit faster than the front, then using the natural tilt to make it easy to slide it backward enough to miss the leveling boxes.

When cranking it back up into place, I ran into the reverse problem with that front bracket.  You have to take the tank up at a bit of an angle so that the front is a bit higher, this lets you get past the leveling boxes, before you shove the tank forward enough to clear the frame rail on the back.

One unexpected problem, on the way up the tank kept rotating around its long axis, with the side closest to the ratchets getting higher quicker.  I had to keep fighting to push it toward the opposite side of the straps to keep it level.
funny
0
informative
1
agree
0
like
2
Doh!
0
No reactions
Members reacted informative:
Oz,
No reactions
Members reacted like:
Oz,Ericb760,
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Image below of the tank after dropping it
funny
0
informative
1
agree
0
like
1
Doh!
0
No reactions
Members reacted informative:
Oz,
No reactions
Members reacted like:
Oz,
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
I ended up purchasing a Spectra Premium FG12S Fuel Sending Unit from O'Reillys.  It was about 3" short of the original hanger.  I cut it up and built a Frankenpump.

I cut the fuel return line at about the half way point down, then used rubber fuel hose to extend it to the right depth.  The bracket for the pump is at the end of that tube, and the fuel level arm is also attached to it.  To stabilize the new setup, I cut an aluminum rod and strapped it to the return line at the top and bottom.  It was important to use metal hose clamps touching the return line and the new stabilizing rod, as the level sensor needs to be grounded, and was originally getting its ground from the return line.

It was then necessary to extend the 3 electrical wires (pump power, fuel level signal, and ground).  I soldered everything and put strain relief zipties in a couple of places.  The + voltage for the pump worried me, as it could accidentally spark to the grounding rods, so I cut a length of fuel hose and slipped it over the connection.  [As an aside, I was astounded to see how small a gap there is manufactured between the + and - leads of the terminals on the pump.  You would think it would spark through the gas, or vapor, and cause the whole thing to blow up.]

I laid the old and new units on top of each other and bend the fuel lever arm until they came out at roughly the same height at the empty and full marks.  Before putting it in the tank I connected up just the ground and sensor wires and turned the ignition key on to verify that the fuel gauge worked as expected at different angles of the arm.

Installing the new unit was a bit tricky, as the new hanger needed to be rotated 90 degrees relative to the old one.  This is because there is a plastic tub inside the tank that prevents the fuel sloshing around so much.  The sensor arm has to fit into that tub in the correct orientation.  A fiber optic camera helped diagnose why it would not go in and seat properly.  Unfortunately, rotating the hanger 90 degrees meant that the holes not the exterior bracket that holds the unit in place, no longer matched the screw holes in the tank.  Six of the holes lined up fine, but the remaining three were reversed.   I did what was absolutely stupid in retrospect.  I got a battery powered drill out and started to drill new pilot holes through the bracket into the tank.  After 3-4 seconds, I start to doubt that drilling into an explosive tank was a bright idea  The solution was actually pretty simple, I took the bracket back off and drilled holes in it to match the ones already in the tank.

I tested it in really short intervals, at first turning the key on for a few seconds, and then going back to inspect for leaks.  I also rented a pressure test kit from O'Reillys and connected it into the fuel line right before the fuel filter.  It is now reading 11 PSI, which is in the range of 10-13 PSI others have recommended.  She started right up and purred happily.

After that it was just a matter of raising the tank back up, bolt it in place, and putting the filler hose and filler relief hose back in place.

Hopefully this Frankenpump will live a long and happy life.
funny
0
informative
1
agree
0
like
1
Doh!
0
No reactions
Members reacted informative:
Oz,
No reactions
Members reacted like:
Oz,
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Newly constructed fuel assembly:
funny
0
informative
1
agree
0
like
1
Doh!
0
No reactions
Members reacted informative:
Oz,
No reactions
Members reacted like:
Oz,
No reactions

Offline Oz

  • Top Post Contributor
  • *
  • Posts: 3551
  • Member since: 2002
  • I own: a Motor Home
  • Year: 1974
  • Make: Winnebago
  • Model: D24 Indian
  • Chassis: Dodge
  • Engine: 440-3
Awesome.  Thanks for the detailed description and photos!
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline tmsnyder

  • Top Post Contributor
  • *
  • Posts: 668
  • Member since: 2016
  • I own: a Motor Home
  • Year: 1976
  • Make: GMC Motorhome
  • Model: Eleganza II
  • Chassis: GMC
  • Engine: 455

Hopefully this Frankenpump will live a long and happy life.

Oh wow I don't want to rain on your parade but I don't think that will work for long. 

What diameter is the steel tubing?   Could you flare it and use a brake line union to splice in the short extension needed?   That's probably the easiest way to make that connection .  Or two steel compression unions, they'd be a little more money but you only need a pair of wrenches to install .  Even a soft solder union would work, silver solder or brazing would be best. 

What's keeping the rubber tubing from swelling up and slipping off the steel lines? Did you flare the ends or anything?

I don't think that ground through the aluminum rod is going to last for long :(

If you put that in the tank I'm afraid it's going to strand you on the side of the road somewhere.

funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
Hi Tmsynder,

You gave me good reasons to pause for a second and worry that it could vibrate loose someday and strand me.

The flexible fuel hose that goes from the pump to the outlet tube is secured to the pump and tube using metal hose clamps.  I did not flare the ends, just slipped the tube over them about 1-1/2".  But, the replacement sender unit itself did not come with flared ends, and would have been the same setup, just with a shorter tube.  The one difference is I used screw down hose clamps, instead of the plastic type locking clamps that were on the old unit, or the metal crimp clamps that came with the new kit.  The concern is then whether the screw clamps will come lose over time and allow fuel to leak out of the high pressure line, and thus reduce pressure to the engine.

The return line is the same setup, but is not critical.  If the extension hose was to fall off, the fuel would still return into the tank.

I should have had the support rod welded onto the existing tube for stability.  In the worst case scenario, that one of the metal clamps comes loose, the pump could start swinging a bit and eventually fatigue the rubber hose (which would be the only thing supporting it). 

The loss of grounding via the rod would only affect the fuel level sensor. The pump gets its power and ground through a two prong connector on top, so is not reliant on the support rod for grounding.  In retrospect, a grounding wire soldered directly to the ground on the level sensor, and patched to the other ground wires would have been a smarter idea.
funny
0
informative
0
agree
0
like
0
Doh!
0
No reactions
No reactions
No reactions
No reactions
No reactions

Offline Superchief90

  • New Poster
  • **
  • Posts: 9
  • Member since: 2020
  • I own: a Motor Home
  • Year: 1990
  • Make: Winnebago
  • Model: Superchief
  • Chassis: Chevy P30
  • Engine: 454-7.4L
In case anyone else has to work on their pump, here are some photos for reference:
* Top view of tank
* Fuel lines
* Original fuel sending unit
* Rupture in the original fuel hose from the pump to the hanger rod
funny
0
informative
1
agree
0
like
3
Doh!
0
No reactions
Members reacted informative:
Oz,
No reactions
Members reacted like:
Ericb760,c farmer,Oz,
No reactions