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| 2.5 Fuel Pressure ? something is not right here (Page 3/3) |
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fierosound
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SEP 07, 07:34 PM
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Leave gas cap off - see what happens...
Just wondering if tank is venting properly or building a vacuum.
Bad pump maybe?
They can be faulty out of the box.
I know it sucks, but it has happened.
Years ago - different car.
Car died on side of road in middle of nowhere. Called for tow truck.
After 1/2 hour of waiting, tried engine and it started !! Cancelled tow.
Repeat two more times before diagnosis of bad in-tank fuel pump.
It would shut down when "hot" and start working again after it cooled off.
You don't have the exact same situation.
Temporarily run 12V power direct to fuel pump connector.
If test light/voltmeter shows pump is getting 12V power even as PSI drops to zero - it has to be the fuel pump.
From 1986 Factory Service Manual...
A picture is worth 1000 words.
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My World of Wheels Winners (Click on links below)
3.4L Supercharged 87 GT and Super Duty 4 Indy #163[This message has been edited by fierosound (edited 09-07-2019).]
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Lou6t4gto
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SEP 08, 10:53 PM
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so, if I were to run a wire from the switched "ON" terminal at the fuse box to the ALCL . the pump would HAVE TO run all the time. and if the pump DID" stop" running,(or stop providing pressure) it would HAVE TO BE the pump itself, correct ?
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Patrick
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SEP 08, 11:41 PM
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| quote | Originally posted by Lou6t4gto:
so, if I were to run a wire from the switched "ON" terminal at the fuse box to the ALCL...
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You've got a 12v source at the cig lighter right by the ALDL port to supply what you need... for test purposes only of course.
| quote | Originally posted by Lou6t4gto:
... the pump would HAVE TO run all the time. and if the pump DID" stop" running,(or stop providing pressure) it would HAVE TO BE the pump itself, correct ?[
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Correct. The ALDL fuel pump terminal is connected directly to the fuel pump.[This message has been edited by Patrick (edited 09-08-2019).]
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Lou6t4gto
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SEP 09, 02:08 AM
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well, that should settle it once and for all if it is truely the fuel pump cutting out Causing the problem. when I get to it, I'll post my findings
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Lou6t4gto
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SEP 15, 06:25 PM
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I NOW HAVE a wire coming from the lighter hot, out to the console, and a wire from the fuel pump plug at the acl out onto the console. not connected, (Just in case) .I took it for a few mile ride, acted just fine ! Maybe just the "threat" of being hotwired Scared It ! LOL
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edfiero
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SEP 16, 02:05 PM
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| quote | Originally posted by Lou6t4gto:
1985 2.5 / automatic. Put in a shrader valve, car will go to exactly 13 PSI "while It's RUNNING". as soon a,s (immediately) when the key is shut off, it goes to" 0"!
not gradually, within a half second ! isn't it supposed to HOLD pressure for at least a couple of minutes ??? Thanks |
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NO. I don't think it will hold the pressure for a couple of minutes. All the TBI cars I've ever checked, lose pressure immediately and go back to zero within 20-30 seconds. Now a SFI/MPI car will hold pressure for minutes, or hours, but not a TBI.
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Lou6t4gto
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SEP 16, 02:13 PM
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this car loses pressure WHILE RUNNING !
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Spoon
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SEP 16, 08:32 PM
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Soooooo, what happen when you tried running with the gas cap loose or off like Fierosound suggested?
Spoon
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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
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Lou6t4gto
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SEP 16, 11:27 PM
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thats the only thing I (so far) forgot to try, the cap. I'll go to get gas and leave the cap loose.
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