Best way to run a wire from the battery to the engine compartment?
 

I'm wiring up a Snow Stage II alcohol injection kit and need a dedicated circuit that is only powered up key on and can handle a full 15 amps draw.

The only circuit I've found (but I'm not very good at looking) that fits this need is the cigarette, pardon me, Cigar lighter circuit which is 25 amps, and is in the trunk (or boot for you English folk)

I'm not terribly electrically savvy, is there a way to get / make a dedicated 15A circuit in the engine compartment?

if not, what is the best way to pull a wire from the cigar circuit to the engine compartment?

Thank you in advance for all your help :)

Without looking at the power distribution I would say the main pos on the starter motor solenoid would be directly fed from the battery, I'll have a look

Look at page 22 in the PDF I linked for you earlier

Regards

Jeff

I would suggest fitting a relay. Wire it up so it is energised from the cigar lighter circuit which is controlled by the ign and take a feed from the main pos on the starter or the alternator via the relay to power your install.

The cigar lighter circuit would handle the small load from the relay but you should fit an inline fuse as close as possible to where you tap into the supply for the relay

Regards

Jeff

Just noticed the "electrical savvy statement"

You will need two inline fuses one 20a which are normaly good for 15a hold for your main feed from the batt pos.

The second would be around 3a for your relay

Regards

Yes,

I'm not terribly savvy electrically, so I prefer to be "spoon fed" instructions like your last post.

Another thank you for you :)

OK,

Getting power from the main pos on the starter is easy enough to find, but which wire (under the hood?) is for the cigar lighter?

If I could impose on your translation skills one more time: If you give me an under the hood location of the cigar circuit wire and color of the wire (see I like being spoon fed) then I can find it.

I'm not really able to read those schematics and translate them into "Oh, this wire"

:)

Oh crap you gonna be renamed newby again now:)

true, true, yes, "Novice" limited expertise when it comes to wiring

Funny, because my father invented the switching power supply. He can talk to electrons and they will tell him what they would do in a given situation.


Hey Brutal, do YOU know which under the hood wire is for the cigar lighter circuit?? Betcha don't (taunt, taunt)

and for round 2, my RealGauge just showed up, but it has instructions I think I can follow, we will see

Dude, if you need a circuit thats hot all the time, isnt there an insulated stud that goes through the front of the housing that the ECM is in? I would just bolt down an eyelet there and call it good. You could put it on the inside too so you wouldnt see your "additional" wiring.

Having a look at it now prob use the ign relay in the engine fuse box to switch your control relay

Ok
The cigar lighters are powered from the trunk fuse box so unless you want to feed wires through the bulkhead Your best bet would to take a feed from the Ignition power bus in the engine fuse box

See page 39 and 45 of the wiring PDF.

I don't have access to An XJ to look at the fuse box but normaly there are unused fuse holders that will be connected to the power bus which would make for a tidier install.

You might find it easier if you print out the circuit diagrams and pen in the circuit your adding, easier to visualise instead of flicking through a PDF file.

Ask your father over for a brew and get him on the case lol

Hope this helps

Regards

Jeff

Yeah, my plan now is to go visit him to get him to help me with the RealGauge install :)

Thanks again for you help.

well hers the problem. Ide have to crack out the diags and test to verify and right now btween work, annula 100 question Jag test and building the engine for a twin screw kenne bell in my Nissan.....well im straped for time. I pretty much have only answer questions on here I know of the top of my head and avoid delving into time consuming diag. esp for free:)
BUT, If it where me Ide flip over the engine compartment fuse box. run the power wire to the inj pump off the fuse box power wire which comes directly from the battery. I fyou want to use a relay. Or I would pin out the wiring underneath finding a wire thats only hot with ign feed and tap into that. Run all the wiring down underneath the box and out to the pump with a inline fuse. You need a DVOM dont use a test light as the pull amps ands if you TEST the worng wire to a module driver you risk blowing the circuit. This is what happens to the climate control modules when the dual climate control valves internally short. Have you decided opn a location for the pump and reservoir? Or are you gonna use the washer reservoir for meth/water?

Brutal,

Thank you for taking the time to respond.

That was my "I wouldn't let just anyone paint THIS fence" Tom Saywer attempt.
I thought the jedi mind trick wouldn't work on you.

Yes I'll be running a relay. Thank you for the suggestion.

Please see the photos in my install post in the engine section of the board to see how I did the install.

I am using the windshield reservoir and strapped the pump to the frame as low as the bottom of the res. I tested it today (using an always live power source) and it works well.

It was a conscious decision to answer:) I have 3 teenagers I raised by myself most of their lives and now more than ever I have to "back door" them into making decisions that are all "theirs" :)