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Topic: Expert Needed: Fuel Pump signal NOT coming from ECM - hair pulling!

in Forum: C3 Electrical

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Expert Needed: Fuel Pump signal NOT coming from ECM - hair pulling!

Posted: 5/30/20 12:43pm Message 1 of 4
vettz
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Joined: 2/26/2006
Posts: 3

Hi,  Bought a 1982 with a fuel pump signal problem... if I jumper the relay pump works and engine pops off!

 

What I have tried so far:

  1. confirmed orange wire by battery (20amp fuse) is ok
  2. replaced ecm same condition
  3. replaced the fuel pump relay

Can somebody tell me where to look for possible issue with wiring? I have probed to connector on ecm and no signal

also confirmed that ground has continuity to ecm..  Please help 🤒




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Re: Expert Needed: Fuel Pump signal NOT coming from ECM - hair pullin

Posted: 5/30/20 6:06pm Message 2 of 4
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Adams' Apple
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Without looking at a wiring diagram. or knowing what specific code(s) you have, I would venture to guess you have an oil pressure sending unit problem. The ECM looks for oil pressure to ground the fuel pump relay, as well as an ignition signal. One or the other...or both, can cause the pump to play dead.




Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Expert Needed: Fuel Pump signal NOT coming from ECM - hair pullin

Posted: 5/30/20 8:15pm Message 3 of 4
vettz
Former Member
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Joined: 2/26/2006
Posts: 3

Thank you Joel! been trying everything, and it was tough to track down!  ended up being corroded fuse for ECM power!  what the hell  LOL  My journey just beginning with this one 😂




Re: Expert Needed: Fuel Pump signal NOT coming from ECM - hair pullin

Posted: 5/31/20 6:01am Message 4 of 4
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Adams' Apple
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

It's always something silly, right? lol




Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

in Forum: C3 Electrical


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