What is draining my battery
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 21
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From: Polo Mo.
What is draining my battery
I have a 1984 that I love but I have an issue right now, I have changed the battery cause I thought it might not be good. Come to find out I here my fuel pump running when the car is off. What do I check first
Help Help?????
Help Help?????
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Yep. agree, the FP relay has power, from the computer. a quick shutoff is to pull the fuse. not sure how the '84 works, but 91 is controled by ecm, so if relay stuck closed, it would have no current from ecm when key is off.
joe
joe
Race Director
Joined: Aug 2007
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From: Whitefish Falls Ontario
St. Jude Donor '08-'09
If unplugging the relay shut the pump off, the relay terminals should be marked A,B,C,D, & E. IF you have a multi-meter check resistance between A and E, if you get 0 ohms or low resistance you need a new relay. If you get infinity check for voltage between C & B on the connector, this is the power signal from the ECM to operate the relay.. 
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 21
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From: Polo Mo.
[QUOTE=ccrazor;1581097400]If unplugging the relay shut the pump off, the relay terminals should be marked A,B,C,D, & E. IF you have a multi-meter check resistance between A and E, if you get 0 ohms or low resistance you need a new relay. If you get infinity check for voltage between C & B on the connector, this is the power signal from the ECM to operate the relay..
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Race Director
Joined: Aug 2007
Posts: 11,889
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From: Whitefish Falls Ontario
St. Jude Donor '08-'09
Two things that you should look at getting is #1 an FSM (factory service manual) and an electrical troubleshooting shop manual supplement. The FSM covers most if not all problems you will have.. The electrical supplement gives you more detailed schematics of the electrical systems..
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 21
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From: Polo Mo.
Help again
[QUOTE=IZ-Boss;1581098148]
Ok my relay is out but the pump is still running does this mean my fuel pump is bad???
thanks in advance IZ-boss
If unplugging the relay shut the pump off, the relay terminals should be marked A,B,C,D, & E. IF you have a multi-meter check resistance between A and E, if you get 0 ohms or low resistance you need a new relay. If you get infinity check for voltage between C & B on the connector, this is the power signal from the ECM to operate the relay..
thanks in advance IZ-boss
Thread Starter
Heel & Toe
Joined: May 2012
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From: Polo Mo.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
is it possible you pulled the wrong relay? 91 relay is marked as the man said A-E. there is a bank of 5, easy to get the wrong one unless it was vibtrating, or hot. it is not the pump. pull the fuse to shut it off while you work or it will be bad.
** as agent 86 said, oil pressure switch could be stuck closed, and it is always hot, direct from battery, on 91. never sure about other years. fuse will kill current to FP.
** as agent 86 said, oil pressure switch could be stuck closed, and it is always hot, direct from battery, on 91. never sure about other years. fuse will kill current to FP.
Last edited by joe paco; Jun 18, 2012 at 10:15 AM. Reason: add **
Race Director
Joined: Aug 2007
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From: Whitefish Falls Ontario
St. Jude Donor '08-'09
If you unplugged the right relay, then you must have a stuck oil pressure switch as Agent 86 suggested. It does not normally operate until the engine has cranked over to build up oil pressure..