It probably reads backwards.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.
Really? That's interesting... So couldn't you reverse the wires to the gauge?derf wrote:It probably reads backwards.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.
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..tedlovesjeeps71 wrote:Really? That's interesting... So couldn't you reverse the wires to the gauge?derf wrote:It probably reads backwards.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.
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?Stuka wrote: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..tedlovesjeeps71 wrote:Really? That's interesting... So couldn't you reverse the wires to the gauge?derf wrote:
It probably reads backwards.
Lol... Guess that's one way.derf wrote:Just remember that full means empty and empty means full.
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.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.
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?acct21 wrote: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.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.
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.
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.
Summit RacingDid you find the sock in a local parts store?
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.I have 2 both running tbi and can run either of them down to virtually nothing (like less than 1 gal.) in tank.
haven't done anything.acct21 wrote: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.I have 2 both running tbi and can run either of them down to virtually nothing (like less than 1 gal.) in tank.
Gotcha, thanks.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.