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fuel pump still on w/ ign off "why did this work" by ceo
Started on: 11-21-2003 04:10 AM
Replies: 4
Last post by: Marvin McInnis on 11-22-2003 04:16 PM
ceo
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Report this Post11-21-2003 04:10 AM Click Here to See the Profile for ceoClick Here to visit ceo's HomePageSend a Private Message to ceoDirect Link to This Post
i unhooked the oil sensor
"to keep the fuel pump from running"

while i searched for the right wrench
to disconnected the battery "resetting the ecm"

when i re-connected the battery
i forgot to re-connect the oil sensor
"of course"
the car ran for about 1 second and quit

then i remembered that oil sensor
"and plugged it back in"

for sum reason the fuel pump
no longer runs while the ignition
is off. i dont really know why it fixed it
"but i suspect" that when i rest the ecm
something code realated must have changed

"hmmm i dunno"
if any of you know for certain let me know
i would rather KNOW if it could have been
code related than just ASSUME that it was..
TIA!

[This message has been edited by ceo (edited 11-21-2003).]

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Old Lar
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Report this Post11-21-2003 09:28 AM Click Here to See the Profile for Old LarSend a Private Message to Old LarDirect Link to This Post
You found the problem. You have a bad connection at the oil sending unit. You need to clean the contacts where the wires plug onto the sending unit.

Best bet is to replace the sending unit. Make sure there is a rubber boot that covers the connection. Water can collect in the top and short out the connections keeping the power onto the fuel pump. Been there, done that.

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JazzMan
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Report this Post11-22-2003 12:36 AM Click Here to See the Profile for JazzManClick Here to Email JazzManSend a Private Message to JazzManDirect Link to This Post
Oh, and if the fuel pump won't run with the oil pressure sender disconnected, you've still got problems. The pressure sender switch is only a backup in case of relay or ECM failure, it is not designed to serve this function full time and will eventually fail.

JazzMan

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ceo
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Report this Post11-22-2003 02:52 AM Click Here to See the Profile for ceoClick Here to visit ceo's HomePageSend a Private Message to ceoDirect Link to This Post
all i know is that what ever the problem was
it doesnt seem to be present now..

i can only assume there was a circut some where that was close and unable to open as it should

which makes me think that between reseting the ECM and disconnecting the oil sensor , i some who interupted the power that was keeping the circut close and things are back to normall

perhaps the fuel pump relay was stuck in the closed position and opened when the power/current flow was noloner avalible to keep it closed

like i said "i dunno" but it certainly left me with a few thoughts to consider..

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Marvin McInnis
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Report this Post11-22-2003 04:16 PM Click Here to See the Profile for Marvin McInnisClick Here to visit Marvin McInnis's HomePageSend a Private Message to Marvin McInnisDirect Link to This Post
 
quote
Originally posted by ceo:

all i know is that what ever the problem was
it doesnt seem to be present now..

...

which makes me think that ... things are back to normall

It will return. Maybe today, maybe next week, or maybe next year, but such problems don't go away by themselves. Consider this episode to be an early warning.

In aviation there is a saying, "The airplane will always try to tell you something's wrong ... before it kills you ... but only if you are listening."

Unfortunately, intermittent problems are the most difficult to diagnose. If I understand you correctly and the FP continued running with the ingition switch off and the OP sensor disconnected, the problem is either in the wiring or the FP relay is failing. My first step would be to swap out the FP relay with a known-good one.

Good luck.

------------------
'88 Formula
Project Testostarossa
"Anything worth doing is worth overdoing."

[This message has been edited by Marvin McInnis (edited 11-22-2003).]

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