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Quantum Fuel 255lph pump problems

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Old Jul 25, 2021 | 11:39 AM
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Quantum Fuel 255lph pump problems

Anyone tried these? I have the f150 1996, rear and front pump. I'm thinking they are duds. I am getting 20psi right after the fuel filter. Filter was changed couple hundred miles ago. Rear tank will trigger lean codes but front do not. Front pump when idling is at 26psi, key on engine off, 36 psi if I cycle the key 5 times, otherwise 20psi. Rear about 15psi while idling. With from pump enable, it runs fine on my newly built 410. Blipping the throttle does not do anything to the pressure. Replaced FPR just for the heck of it. Unplugging vacuum does nothing, which I assume means a faulty pump.
 
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Old Jul 25, 2021 | 11:41 AM
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I don't know what pressures the 1996 OBD-II rigs should be running at, but that seems low.
 
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Old Jul 25, 2021 | 11:50 AM
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I'm curious to see what the old stock pump reads. Just hating f'ing with the bed again.
 
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Old Jul 25, 2021 | 12:14 PM
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Well i was wrong, if I rev the engine enough it does move the needle downwards. I'm thinking weak pumps.
 
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Old Jul 25, 2021 | 12:50 PM
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Should be 32-35psi idling and 40-45psi with vacuum removed from the regulator. Your pumps are very weak.
 
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Old Jul 25, 2021 | 12:56 PM
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Originally Posted by Conanski
Should be 32-35psi idling and 40-45psi with vacuum removed from the regulator. Your pumps are very weak.
Yeah removing the regulator does nada. How in the world can 2 pumps be weak? The rear is even weaker than the front. I'm going to bypass the fuel lines and just go straight to the pump and see what the pressure is.
 
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Old Jul 25, 2021 | 01:02 PM
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Is there a solid 12.5v at the pumps?
 
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Old Jul 25, 2021 | 01:06 PM
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Did you install those pumps inside the OEM fuel delivery module or did you delete them? The FDM contains check valves to prevent cross flow between tanks and without that half the fuel volume(and presure) would just spill into the other tank.
 
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Old Jul 25, 2021 | 01:21 PM
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ok had to cycle key 10 times, only managed to get 30psi right at the tank supply line. Time to return these pieces of crap pumps.
 
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Old Jul 25, 2021 | 01:24 PM
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Originally Posted by Conanski
Did you install those pumps inside the OEM fuel delivery module or did you delete them? The FDM contains check valves to prevent cross flow between tanks and without that half the fuel volume(and presure) would just spill into the other tank.
Well i got them because they had the FDM, 167 bucks for 1. I'm out over 300 bucks and nothing to show for it. I'm going to hook up the stock pump and see what that reads. Just have to rig something to pull the bed off. I could do it with the bed jacked to one side but easier with bed removed.
 
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Old Jul 25, 2021 | 01:30 PM
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Oh I read a thread earlier where the guy found that the relay was bad, had the same psi as mine with key on, engine off. I swapped the relays around and it did not change anything. Would it be worth getting a brand new relay?
 
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Old Jul 25, 2021 | 01:32 PM
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Being you can't buy OE pumps anymore I put a carter FDM fuel pump in my front tank. After 3 weeks the FDM check valve has failed and has over filled the tank to the point it was running on the ground while driving. Frankly at this point I wish I would have just put one new 33 gallon tank from a Bronco in the rear and **** canned the front tank. Then I could just run a fuel pump from the likes of a Mustang with just 1 return line and no FDM to mess with.
 
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Old Jul 25, 2021 | 01:38 PM
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Originally Posted by Zrt1200
Being you can't buy OE pumps anymore I put a carter FDM fuel pump in my front tank. After 3 weeks the FDM check valve has failed and has over filled the tank to the point it was running on the ground while driving. Frankly at this point I wish I would have just put one new 33 gallon tank from a Bronco in the rear and **** canned the front tank. Then I could just run a fuel pump from the likes of a Mustang with just 1 return line and no FDM to mess with.
Everything's made in china now...can't get anything decent. I think if my stock pump reads any decent amount of pressure I might just run it that way. It's probably not enough but oh well. I'm just tired of this project. There are more aftermarket for the fox bodies, might head that way. Put my stocker 302 back in and call it lesson learned.
 
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Old Jul 25, 2021 | 03:31 PM
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I installed one those 255 LPH from Quantum
this past spring and it failed on me after a couple days. I put the stock OEM pump back in it that has 235k miles on it and it works great. I’ll add Quantum has good tech support and refunded my money without hassle.
 
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Old Jul 25, 2021 | 04:05 PM
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Originally Posted by EllieMae94
I installed one those 255 LPH from Quantum
this past spring and it failed on me after a couple days. I put the stock OEM pump back in it that has 235k miles on it and it works great. I’ll add Quantum has good tech support and refunded my money without hassle.
Good to know! Well i found the issue, I tested the amp draw and it's only doing 6.5amp key on, engine off. No wonder I can't get 40psi or more. according to walbro chart it will give me 20psi which is right around what I'm seeing. The rear is worse like I thought at 5.8 amp. I'm going to need around 9amp draw, so I am guessing the wiring needs to be upgraded. Too bad they don't make the 190 version, only 255. Anyone know how I can accomplish this? Oh and no where on their site did they say you had to upgrade your wiring.
 
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