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What voltage do fuel injectors operate at? by tesmith66
Started on: 08-21-2013 01:54 PM
Replies: 9 (3630 views)
Last post by: armos on 08-22-2013 12:12 AM
tesmith66
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Report this Post08-21-2013 01:54 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
I want to clean some fuel injectors by running spray cleaner through them. Every how to I see on the net says to run 5V to them to fire them. Does it have to be 5V? My battery charger can supply 6V. Is that too much? Would a 5V phone charger have enough amperage to work?

------------------
1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

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trotterlg
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Report this Post08-21-2013 01:59 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
They run at 12 volts, a 9 volt battery usually will fire them. I don't think 5 volts will do it most of the time. Some times even 9 volts won't pull them in. Larry
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tesmith66
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Report this Post08-21-2013 02:02 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
Then why do all of the how-to's say 5? Are they computer geeks with power supplies laying around?
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trotterlg
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Report this Post08-21-2013 02:17 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
Who knows, 12 volts is supplied to the injectors and they are turned on by grounding the return wire. That is how it works. Looks like you are another person who believes what you read on the internet. Larry
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fieroguru
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Report this Post08-21-2013 02:18 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
My test rig (4 injectors wired in parallel) runs off a 9V battery. In the past I have done all 8 injectors with a car battery.

I have heard people concerned with using 12V and leaving the injectors on steady - potential to overheat the coil.
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tesmith66
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Report this Post08-21-2013 02:47 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trotterlg:

Who knows, 12 volts is supplied to the injectors and they are turned on by grounding the return wire. That is how it works. Looks like you are another person who believes what you read on the internet. Larry


That was a bit harsh. If that was the case, would I have asked here?
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Pyrthian
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Report this Post08-21-2013 03:59 PM Click Here to See the Profile for PyrthianClick Here to Email PyrthianSend a Private Message to PyrthianEdit/Delete MessageReply w/QuoteDirect Link to This Post
I always thought 12v too.
is it maybe that 5v is the ECM signal, and the injector driver puts it up to 12v?
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tesmith66
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Report this Post08-21-2013 04:08 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
The wiring diagrams show it as 12V with the switching performed on the ground side, and I was planning on using 12V, but all of the info I saw online said 5V. Just wanted some verification.
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Lou6t4gto
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Report this Post08-21-2013 05:17 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
They all have 12 volts all the time and are fired by Grounding them. Some systems are "Batch fired" some are not,
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armos
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Report this Post08-22-2013 12:12 AM Click Here to See the Profile for armosSend a Private Message to armosEdit/Delete MessageReply w/QuoteDirect Link to This Post
It would be nice if they ran on a regulated supply like 5 volts, it would help the ECM to control them with better accuracy. But they run on battery voltage, and the ECM attempts to tweak the fuel pulse slightly based on what the voltage at that moment happens to be. The variable voltage is a source of error.
I assume that a regulated 5 Volt supply would have to handle lots of current to drive the injectors, making it uneconomical.
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