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weird no start on my87 gt mustang

 
Bobpa87
New User
Posts: 2
Joined: 09/13
Posted: 11/20/13 01:45 PM

jack the car about one foot off the ground and it starts right up.on the ground the fender mounted solenoid(relay)just clicks.I just changed the negative wire from the solenoid to the starter which was very corroded;same!The starter is pretty new ,solenoid is brand new,battery is good battery terminals new.Any help would be appreciated;Thanks.Bob  

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wayne712222
New User
Posts: 14
Joined: 10/13
Posted: 11/20/13 08:41 PM

sounds like you have lost your battery negative post to the body connection..

or

the engine to body connection usually on the back of the cylinder head..


try this...

take your jumper cables..

work with both red and black..   hook both clamps on one end to the negative battery terminal..   hook the other ends .. one to the engine block and one to the body...

attempt to start the engine...

if you can get it started...

perform this test... while carefully disconnecting the jumper cables..


headlights on.. engine running.. digital meter set to 20 volts DC..


1.  negative battery post to the positive battery post... 14.1 to 14.8 volts..

2.  Negative battery post to the engine block.. 0.04 volts dc max .

3.  Negative battery post to the body..  0.02 volts DC max..

4.  Engine block to the Body... 0.02 volts DC..

if you get MORE THAN 0.04 and 0.02 volts on test 2, 3 and 4.. you have a bad ground connection

i have more info that will come later..

try the junper cables to its self..

post results..  

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wayne712222
New User
Posts: 14
Joined: 10/13
Posted: 11/21/13 02:07 AM

ground locations under the hood...

2 on the top of the core support.. perhaps 3 on some models..

one on the inner fender next to the starter relay..

one on the bottom corner of the block.

and one not show here.. a braided strap between the back of the engine and the firewall..  this one is really important..  as it also supplies ground connection between the engine and the body for the shortest route for the electrons for the computer..

189674Ba Dfbd 4746 8B76 626Dd7372e40 Zps39a79681  

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wayne712222
New User
Posts: 14
Joined: 10/13
Posted: 11/21/13 02:15 AM

92 Mustang 50 Eeciv Wiringlocator Zps3451be8b


2001Rangerfirewallgroundstrap

92 Mustang50ecmconnector Zpsbf55ea49


Ground Strap 15 Inch Zpsbc9293c1

Fordcoresupportgrounds Zps48c74c23

Ford Starter Solenoid Flat  

Post Reply
Bobpa87
New User
Posts: 2
Joined: 09/13
Posted: 12/04/13 12:54 PM

Wayne;thanks for the very informative reply.I had my wife turn the ignition key while I moved the braided engine to body ground stap and it started right up.I removed the terminal to the body and cleaned it as well as removing the factory paint which allowed only the screw to make a ground.I order a new braided ground strap and added a ground wire from the engine to negative battery cable.Thanks for all your help! Bob  

Post Reply
wayne712222
New User
Posts: 14
Joined: 10/13
Posted: 12/05/13 01:49 PM

great...

glad i was able to help you find the issue..

please run the 4 part voltage drop test when you are done..


engine running.. headlights on...  digital volt meter to 20 volts DC..

1.  Negative battery to the positive battery post.. 14.1 to 14.8 volts..

2.  Negative battery to the engine block.. 0.04 volts DC max..

3.  Negative battery to the body.      0.02 volts DC MAX..

4.  Engine block to the Body.     0.02 volts DC MAX...


the 4/100ths of a volt or 2/100ths of a volt show that the ground connections between the parts are properly connected and the  tiny voltage shown is just from the actual resistance in the copper wire..  

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