Hey all ,stupid question ..im working on a 99 hoe lt , i noticed the return line on the fuel pump wasnt putting out very much flow ( engine is off) i went straight to the pump with 12v . Should it be a weak flow ? I did notice the ground wire i was holding to the frame got hot while i was doing this ..
Fuel pump return
- Thread starter Hpb99
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strutaeng
Full Access Member
What are you trying to do?
I've never actually measured how much flow there's in a return fuel line, but I don't expect there to be much. Return line is basically there to bleed of excess fuel to maintain the specified fuel pressure, controlled by the FPR.
I've never actually measured how much flow there's in a return fuel line, but I don't expect there to be much. Return line is basically there to bleed of excess fuel to maintain the specified fuel pressure, controlled by the FPR.
Well right now , im having issues tryin to get the truck to start.. not getting spark or fuel . So i been tracing items to make sure theyre not the cause .i had a pump issue 1yr ago then replaced it 3 times since with a new ( not reman) unit. It puts out flow but doesnt really seem to put out as much. I found this by accident trying to get fuel outa the tank for my generator..
strutaeng
Full Access Member
Understood.
What is your static fuel pressure when the pump primes? How much psi? Does it hold that pressure for 10 minutes? If not, how much does pressure drop?
Are you still running the poppet -type spider injectors? Those require the upper end of pressure, like 55 psi+ to fire the engine. The MPFI upgrades will fire the engine with lower pressure. I don't remember what that pressure is tho.
Also, there should be a blue wire hanging out of your fuseblock that's meant to prime the pump without you crawling down to jump wires. I've never had to use, just know it's there.
What is your static fuel pressure when the pump primes? How much psi? Does it hold that pressure for 10 minutes? If not, how much does pressure drop?
Are you still running the poppet -type spider injectors? Those require the upper end of pressure, like 55 psi+ to fire the engine. The MPFI upgrades will fire the engine with lower pressure. I don't remember what that pressure is tho.
Also, there should be a blue wire hanging out of your fuseblock that's meant to prime the pump without you crawling down to jump wires. I've never had to use, just know it's there.
By "static fuel pressure" do you mean without cranking the engine? Key on, engine off?
And for holding pressure, do you mean after the key is turned off?
To be honest guys not sure dont have any way to test it. Pump wont fire up even if i bypass the relay.. as for the injector on this truck it has a squirter not a spider setup. I did notice when i go straight to the pump with 12 v the pimp doesnt push fuel very far on the ground..& seems quierter than normal.
strutaeng
Full Access Member
Yes. I started calling it "static" because it makes more sense to me
."Holding pressure" yes.
Brother, go buy a fuel pressure gauge at the local parts store. I've joked here that a fuel pressure gauge should be like included in a "old Chebby truck starter pack." But to be honest, anyone working on these trucks needs to own one. So many fuel pumps get replaced because guys think they aren't getting fuel w/o actually hooking up a gauge. It's great business for the local parts stores tho. But I digress...
And if you need to get by for now, many auto parts stores will 'rent' a fuel pressure gauge kit; pay for it on a credit card, and get the full refund when you return it on time.
But it sounds like the fuel pump isn't getting commanded on.
But it sounds like the fuel pump isn't getting commanded on.
Thank you guys , i kinda think im just going to replace the pimp again( under warranty) for the simple reason that an old parts guy told me . He said fuel companies change from winter blend to summer blend & it tends do strip the lubrication from the pumps causing them to go out & i havent been putting a pint of oil in the tank lately.. I will pickup a pressure gauge again also, then i know ill find my other one .. Thanks for the poi the tho ...
" He said fuel companies change from winter blend to summer blend & it tends do strip the lubrication from the pumps causing them to go out & i havent been putting a pint of oil in the tank lately.."
Where do people come up with this stuff?
What is a squirter set up??
Where do people come up with this stuff?
What is a squirter set up??
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