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low voltage, crappy idle, bucking.... help

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Old Apr 12, 2007 | 06:07 PM
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low voltage, crappy idle, bucking.... help

Well I had my fuel system redone and afterwords, the car wouldnt idle due to low voltage. I changed the oddyssy pc680 out for a braille carbon racing battery. Everything was fine. 2 days later the car was back firing and died do to low voltage again. I changed out the alternator today and everything cranked up fine. Drove home and on the way home the car started bucking like crazy and back firing going into my neighborhood. finally died on my street and coasted to my house. Anyone have an idea as to what the issue is? I am still breaking in a new motor and it hasnt been tuned yet. Major Mods are a streetport, microtech lt-10s, single t67, fuel system with 4 - 1680cc injectors.

Why do I keep losing voltage. Shouldnt it still run on just the alternator (even though it is bad to run on just the alternator)?
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Old Apr 12, 2007 | 08:14 PM
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When having battery/alternator problems it is not a bad idea to replace both at the same time. A failing alternator will kill a battery, and in turn a failing battery will kill an alternator. Might not be a bad idea to take each in and get them tested, even though I doubt they would go bad that fast.

Also might want to check the coils, if it's sputtering you might not be getting spark. Basically just check over the basics, air, fuel, spark...

- James
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Old Apr 12, 2007 | 08:24 PM
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rynberg's Avatar
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When you say four 1680cc injectors, are you saying you are using those as primaries as well? Why in god's name would you run 1680cc primaries? There's no way that thing is ever going to have any kind of stable idle.
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Old Apr 12, 2007 | 09:33 PM
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the idle has always been fine until i have been having voltage issues. the problem here lies somewhere in the electrical system. Voltage has been low and it seems like the alternator isnt always sending power back to the battery. When the voltage gets low its like the coils aren't getting power and it misfires.
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Old Apr 12, 2007 | 09:34 PM
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also, i am not running half of the electrical stuff in the car. as a matter of fact, most of the harness isnt even hooked up i don't think.
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Old Apr 13, 2007 | 02:27 PM
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bump for help
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Old Apr 13, 2007 | 02:33 PM
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did you go have your battery/alt tested? look into the coils/spark? we can't help if your not going to help eliminate potential problems...
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Old Apr 13, 2007 | 02:57 PM
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have u added grounds or upgrade the grounding system.
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Old Apr 13, 2007 | 03:22 PM
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My problem sounds exactly the same. Here is a thread I posted up. https://www.rx7club.com/3rd-generation-specific-1993-2002-16/need-help-burnt-up-3-odessey-pc680s-576625/

I am going to be trouble shooting this over the next week or so. I have a full size optima yellow that I am using as well as relocating it to the hatch area.

One thing I heard from a old hot rodder is that some times the solenoid on the starter can keep drawing power from the system even though it's not engaging. I have another starter here to try as well.

Anyway give my thread a read, and good luck. I will be watching this thread and if I fix my problem I will post here as well.
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Old Apr 13, 2007 | 03:49 PM
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im going to test the battery and alternator right now.
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Old Apr 13, 2007 | 05:00 PM
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alternator checked out fine but the battery needs to be charged before tested.
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Old Apr 14, 2007 | 09:30 PM
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well i think i may know what the problem is. I didnt replace the battery and alternator at the same time. the pc680 died and i got a braille carbon. then replaced the alternator but at that time the battery was already done. autozone tested the alt as perfect but the battery is bad after 2 days. i will see if that is all on monday when i get a new battery.
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Old Apr 15, 2007 | 05:43 AM
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Yea, that might fix it (hopefully). The one thing I learned over the years is start with the easy/obvious stuff, even if it seems stupid. Getting the battery/alternator tested is easy and has solved many a problem for me over the years haha. Hopefully the battery you bought came with some kind of warranty so you don't have to buy another one.

- James
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Old Apr 15, 2007 | 06:29 AM
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Originally Posted by rynberg
When you say four 1680cc injectors, are you saying you are using those as primaries as well? Why in god's name would you run 1680cc primaries? There's no way that thing is ever going to have any kind of stable idle.
I have 4 1680 cc injectors and idles perfect at 900 rpms on a TEC3. I've also seen these idle absolutely perfectly with a haltech e6K and 900, rock solid.

Anthony
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Old Apr 15, 2007 | 06:32 AM
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Originally Posted by mqt_hockey6
well i think i may know what the problem is. I didnt replace the battery and alternator at the same time. the pc680 died and i got a braille carbon. then replaced the alternator but at that time the battery was already done. autozone tested the alt as perfect but the battery is bad after 2 days. i will see if that is all on monday when i get a new battery.
Let me know how this works out.

Anthony
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