get to ½ tank gas and '88GW will stall

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pjwoody88
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get to ½ tank gas and '88GW will stall

Post by pjwoody88 »

I have installed EFI on my 88 gw with an in-line fuel pump. Runs great until I get to ½ tank and it will stall when the fuel moves to the forward portion of the tank. Is there anything that can be done to the pickup that will allow it to reach more of the tank? Should I just replace the poly tank with a baffled tank? Would a fuel command center do the trick? I’m not looking to do any wheelin. Just want to be able to drive it on extended trips and not get gas four times. Thanks.
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

Mine has this same issue. Infuriating to say the least. May try swapping the tank from my '89 suburban in to see if that helps. The suburban is TBI 350 and the pump is in the tank. Wonder if the sending unit works the same.
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derf
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Re: get to ½ tank gas and '88GW will stall

Post by derf »

tedlovesjeeps71 wrote:Mine has this same issue. Infuriating to say the least. May try swapping the tank from my '89 suburban in to see if that helps. The suburban is TBI 350 and the pump is in the tank. Wonder if the sending unit works the same.
It probably reads backwards.
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

derf wrote:
tedlovesjeeps71 wrote:Mine has this same issue. Infuriating to say the least. May try swapping the tank from my '89 suburban in to see if that helps. The suburban is TBI 350 and the pump is in the tank. Wonder if the sending unit works the same.
It probably reads backwards.
Really? That's interesting... So couldn't you reverse the wires to the gauge? Image
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Stuka
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Re: get to ½ tank gas and '88GW will stall

Post by Stuka »

tedlovesjeeps71 wrote:
derf wrote:
tedlovesjeeps71 wrote:Mine has this same issue. Infuriating to say the least. May try swapping the tank from my '89 suburban in to see if that helps. The suburban is TBI 350 and the pump is in the tank. Wonder if the sending unit works the same.
It probably reads backwards.
Really? That's interesting... So couldn't you reverse the wires to the gauge? Image
No, the difference is in the resistance, and how many ohms equals full vs empty. Almost every manufacturer changed in the mid 80's to be the opposite of what it was previously..
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

Stuka wrote:
tedlovesjeeps71 wrote:
derf wrote:
It probably reads backwards.
Really? That's interesting... So couldn't you reverse the wires to the gauge? Image
No, the difference is in the resistance, and how many ohms equals full vs empty. Almost every manufacturer changed in the mid 80's to be the opposite of what it was previously..
Not to derail the thread but how are folks using suburban tanks dealing with it then? I'd love to swap but going from only using half the tank with a dancing gauge to having lots of fun but not having a working gauge at all seems like only a partial win. Is there a replacement sending unit/pump/pickup that drops in the sub tank?
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derf
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Re: get to ½ tank gas and '88GW will stall

Post by derf »

Just remember that full means empty and empty means full.
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

derf wrote:Just remember that full means empty and empty means full.
Lol... Guess that's one way. ImageImage
Or maybe install a stand alone fuel gauge.

Danbert
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Re: get to ½ tank gas and '88GW will stall

Post by Danbert »

Carefully open your gauge cluster and black out the existing E and F and use white out to make new ones. :D


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acct21
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Re: get to ½ tank gas and '88GW will stall

Post by acct21 »

pjwoody88 wrote:I have installed EFI on my 88 gw with an in-line fuel pump. Runs great until I get to ½ tank and it will stall when the fuel moves to the forward portion of the tank. Is there anything that can be done to the pickup that will allow it to reach more of the tank? Should I just replace the poly tank with a baffled tank? Would a fuel command center do the trick? I’m not looking to do any wheelin. Just want to be able to drive it on extended trips and not get gas four times. Thanks.
The aftermarket sending units on the later GW have a known issue, where the pickup tubes are nearly 2" shorter than OEM -- so they sit almost 3" off the bottom of the tank. That leaves a huge amount of fuel in the tank when the bottom of the pickup starts sucking air.
Image

When I installed EFI on my '90 I flared the end of the pickup tube with my flare tool, and added a ~6" piece of submersible 3/8" FI hose. Then added an aftermarket strainer sock that sits down in the little square recess in the bottom of the later coffin tank. So my pickup is in the absolute dead bottom of the tank.
Image
Image

I also run a surge tank -- but not the FiTech FCC. Those things have been nothing but problems since they introduced them. I run one from RobbMc Performance (PS500) that uses a standard Walbro pump inside.

https://www.robbmcperformance.com/produ ... surge.html

Between the two modifications, I can run my '90 until the low fuel light comes on. It has never cavitated/sucked air. As a bonus, I have the stock fuel system from the pickup all the way to where the soft lines came off the mechanical pump. The low pressure mechanical pump feeds the high pressure pump in the surge tank. If I need to replace the high pressure pump, it's right there under the hood -- I put it where the charcoal canister used to sit.
Last edited by acct21 on Sun Feb 03, 2019 11:33 am, edited 1 time in total.
1990 GW with HD towing package -- everything works! (today, anyway)
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

acct21 wrote:
pjwoody88 wrote:I have installed EFI on my 88 gw with an in-line fuel pump. Runs great until I get to ½ tank and it will stall when the fuel moves to the forward portion of the tank. Is there anything that can be done to the pickup that will allow it to reach more of the tank? Should I just replace the poly tank with a baffled tank? Would a fuel command center do the trick? I’m not looking to do any wheelin. Just want to be able to drive it on extended trips and not get gas four times. Thanks.
The aftermarket sending units on the later GW have a known issue, where the pickup tubes are nearly 2" shorter than OEM -- so they sit almost 3" off the bottom of the tank. That leaves a huge amount of fuel in the tank when the bottom of the pickup starts sucking air.Image

When I installed EFI on my '90 I flared the end of the pickup tube with my flare tool, and added a ~6" piece of submersible 3/8" FI hose. Then added an aftermarket strainer sock that sits down in the little square recess in the bottom of the later coffin tank. So my pickup is in the absolute dead bottom of the tank.
Image
Image

I also run a surge tank -- but not the FiTech FCC. Those things have been nothing but problems since they introduced them. I run one from RobbMc Performance (PS500) that uses a standard Walbro pump inside.

https://www.robbmcperformance.com/produ ... surge.html

Between the two modifications, I can run my '90 until the low fuel light comes on. It has never cavitated/sucked air. As a bonus, I have the stock fuel system from the pickup all the way to where the soft lines came off the mechanical pump. The low pressure mechanical pump feeds the high pressure pump in the surge tank. If I need to replace the high pressure pump, it's right there under the hood -- I put it where the charcoal canister used to sit.
That’s some good info, thanks. I may have to find my flaring tool and give that a try. Did you find the sock in a local parts store?
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babywag
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Re: get to ½ tank gas and '88GW will stall

Post by babywag »

I have 2 both running tbi and can run either of them down to virtually nothing (like less than 1 gal.) in tank.
One has an in tank pump other has frame mounted pump.
You have something wrong w/ pickup placement or it's sucking air somehow.
-Tony
'88 GW (aka Babywag)

acct21
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Re: get to ½ tank gas and '88GW will stall

Post by acct21 »

Did you find the sock in a local parts store?
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acct21
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Re: get to ½ tank gas and '88GW will stall

Post by acct21 »

I have 2 both running tbi and can run either of them down to virtually nothing (like less than 1 gal.) in tank.
What have you done to extend the pickup in the one you're running the frame-mounted pump with? Because if you've done nothing, you can't be getting down to a gallon in the tank -- not with the end of the pickup sitting 3" off the bottom. I mean... a gallon of gas in a late GW coffin tank would be like 3/4" deep -- max. That defies physics.
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babywag
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Re: get to ½ tank gas and '88GW will stall

Post by babywag »

acct21 wrote:
I have 2 both running tbi and can run either of them down to virtually nothing (like less than 1 gal.) in tank.
What have you done to extend the pickup in the one you're running the frame-mounted pump with? Because if you've done nothing, you can't be getting down to a gallon in the tank -- not with the end of the pickup sitting 3" off the bottom. I mean... a gallon of gas in a late GW coffin tank would be like 3/4" deep -- max. That defies physics.
haven't done anything.
a correct sender pickup/screen rests on bottom of the tank not sure where you get 3" from bottom?
there is also a small depression in bottom of tank so pickup sock is actually below rest of tank.
I have filled it with 19gals. on many many occasions.
-Tony
'88 GW (aka Babywag)

acct21
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Re: get to ½ tank gas and '88GW will stall

Post by acct21 »

This is the aftermarket sending unit mounted in a 1990 tank that I cut the front out of (since the junkyard had already drilled a huge hole in the bottom). The end of the pickup tube is nearly 3" off the bottom -- if you consider the measuring tape isn't even in the bottom of the little depression, it's even further from the bottom of that.

Image

The pickup screen doesn't let you suck gas from any deeper in the tank... after all, it's not a solid tube -- it's a screen. The end of the pickup tube is what determines how far off the bottom you are sucking gas (or air).

Who knows... maybe I got a defective aftermarket sender -- but I think we all know they're shorter than the OEMs were. I had issues running out of gas with 1/4 tank showing on the gauge, but this solved the problem for me.
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babywag
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Re: get to ½ tank gas and '88GW will stall

Post by babywag »

The oem's I've had apart obviously much longer.
Your "fix" shouldn't be needed but sadly most aftermarket parts are crap these days.

I have never even opened up my '90 tank and assume it's an oem sender in there. My '88 was original and if my memory is accurate? seems to me the tube was all way to bottom and sock laid on bottom.
I actually put over 20gals. in '88 last time I ran outta gas in it.
-Tony
'88 GW (aka Babywag)
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

I may pull my sending unit tomorrow if the weather cooperates. Any idea what the length is of the stock vs short replacement units is? 3”s short doesn’t help so much as I can’t cut off the end of my tank to measure.
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babywag
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Re: get to ½ tank gas and '88GW will stall

Post by babywag »

If you can't utilize almost the whole tank there is obviously a problem.
Most folks that have 1/4 tank issues are simply missing the pickup tube/screen or it's broken/breaking apart.

To check correct depth you just need a ruler and a stick or something if you don't want to stick your tape measure into fuel.
With sender out of tank measure how long it is, then compare to how deep the tank is.
-Tony
'88 GW (aka Babywag)
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tedlovesjeeps71
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Re: get to ½ tank gas and '88GW will stall

Post by tedlovesjeeps71 »

babywag wrote:If you can't utilize almost the whole tank there is obviously a problem.
Most folks that have 1/4 tank issues are simply missing the pickup tube/screen or it's broken/breaking apart.

To check correct depth you just need a ruler and a stick or something if you don't want to stick your tape measure into fuel.
With sender out of tank measure how long it is, then compare to how deep the tank is.
Gotcha, thanks. ImageImage
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