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Fuel Pumps Expertise Sought

JavaG66

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1986
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Ford
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Transmission
Automatic
2WD / 4WD
2WD
At the Schrader valve on the injector rail:
KOEO- 5 psi
Idle - 30 psi
Faster- 28 psi
Truck cranks up and drives fine, does not idle well, is weak/misses at low rpms and smells like i'm just shooting raw gas straight out the back end. Anything above an idle it seems to run fine. So in the process of trying to fix this idle issue, I'm checking the fuel system. Both pumps whirr when the key is turned on, if I disconnect power to the pump on the chassis, I still can hear the pump in the tank run for those two seconds. The truck won't start with that high pressure pump off line.
Thanks for any insight you can provide.
So as I'm asking all this about fuel pumps, another question occurred to me: If an injector was stuck open, would it be the likely cause of the described issue? (I'm hoping not because they are a pain to get to.)
 


RonD

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Running pressure looks OK, 30-35psi would be "normal".

Key off pressure should hold above 20psi, for a few months.

Since you think it is running rich at idle I would check Fuel Pressure regulator(FPR)
FPR is on the fuel rail and is connected to the fuel return line, it also has a vacuum line attached.
FPR has a rubber diaphragm valve inside, if that valve starts to leak then raw fuel is sucked into the intake via that vacuum hose.
Remove and check that vacuum hose for fuel or fuel smell.

Stuck open injector would flood that cylinder, steady miss, sticky injector could be the problem, run some Seafoam in the gas tank
 

JavaG66

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Thanks for your comments, Ron. Based on a previous post of yours, I sniffed the vacuum tube to the FPR and thought I smelled gas, so I replaced it. But unless I got a bad one off the shelf, that wasn't the problem. I'll give SeaFoam a shot- it's easy and sometimes actually helps.
 

RonD

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I put a can of Seafoam in each fuel injected vehicle once a year, certainly smooths out my '94's idle, it isn't bad just definitely notice a difference after 1/2-3/4 tank.

22 year old injectors, original FPR and fuel pump, I have changed the filter, lol.
 

JavaG66

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Automatic
2WD / 4WD
2WD
22 year old injectors, original FPR and fuel pump, I have changed the filter, lol.
Well until my snoz misled me, my 86 had the original FPR also. And I discovered the fuel filter a couple of years back. Not much else is original though except the cruise control and faded paint.
I added SeaFoam; I'll post the results in a week or so as I generally put less than 10 miles a day on it now.
 

RonD

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Clean PCV Valve and hose, also vent hose.

An engine needs to get up to operating temp for at least 15 minutes, so 20 minutes running, to heat up and burn off moisture in the block/valve cover areas.

So drive longer than 10 miles at least once a week
 

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