T O P I C R E V I E W
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xchpstang
Member # 1206
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posted
(Ignore the first incomplete post) To those who have their battery in the trunk:
Did you run ground wires back to the engine block and to the frame near the washer bottle? If not, did this affect your performance? I recently installed Edelbrock heads, TFS intake, Comp Cam, BBK full lengths, off road H-pipe, Pro-M 75 meter, and MAC cold air induction. The battery had been relocated to the trunk a few weeks before. The car now runs terrible. It "wheezes" just to get to 4K RPM. When I let off the gas I hear backfiring and popping through the exhaust. The car feels like it has less power than stock. I haven't even tried full throttle because like it's running on 5 cylinders. I read at the Pro-Flow website that not running ground wires back to the engine compartment will cause this lean condition and backfiring due to the EEC not getting proper ground. Would running ground wires solve this problem and if not where should I start? Any suggestions would be appreciated before I drive the car off the cliff.
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shade-tree
Member # 298
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posted
I thought the ground for a trunk battery is supposed to be the frame rail closest to the trunk? Only long run should be the 'hot' wire, right up to the stock location (near the coil)?
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xchpstang
Member # 1206
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posted
This is exactly where I have the ground: a short wire goes from the negative terminal to the nearest frame rail in the trunk. However Pro-M tech support said this was exactly the WRONG way to do it on a fuel injected Mustang. They told me that for proper grounding of the EEC and thus proper operation of the computer I needed to run ground wires back to the original places in the engine compartment (the frame near the washer bottle and the engine block.) I am still puzzled as if this is what's causing all the mentioned woes.
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1sicklx
Member # 1018
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posted
the only wire going to the front on mine is the positive, the grond is bolted to the frame...
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st5150
Member # 51
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posted
If you have a digital volt meter, load up the car electricly (run the A/C, defefroster, electric fan, ratio, headlights + high beams, ect) and measure the voltage from the point where you grounded it in the trunk to where the EEC grounds on next to the washer fluid cap. Then measure the voltage from the point where you grounded it in the trunk to where the motor grounds to the firewall. You should get almost no voltage. If you do get any significant amount of voltage, then that means the chassis has too much internal resistance and you'd probably benifit from running an extra ground strap to the front of the car. Even if you're unsure, extra ground straps can never hurt you
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PunkINa5.SLOW
Member # 10
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posted
quote: Originally posted by st5150: Even if you're unsure, extra ground straps can never hurt you
There is the key to your fix
Run another ground strap
Like ST says cant do anything, but good
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xchpstang
Member # 1206
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posted
Thanks for all your input guys. I'm off to my nearest hardware store to buy about 20' of 2 gauge welding cable and 20' of 10 gauge wire. I hope this solves my problem.
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shade-tree
Member # 298
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posted
nah that stuff is too heavy. get the silver braided cable with 'eyes' so that you can bolt it to the frame.
no need to weigh the car down with another 10-20 lbs. of welding cable!
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