Chris' '90 Toyota Celica
Summer '03 Mod List -
September 25, 2017
Issue: Inconsistent voltage - Since relocating
the battery to the trunk, I've noticed inconsistent voltage at various times
and at various points on the car.
Solution: Although I'm 98% certain the
variations I've noticed are due to poor grounding, I will go the extra
mile or so and thoroughly redesign the power distribution units under both
the dash and the hood, as well as upgrade the alternator output wire to a
larger gauge. I'll also implement one of those
grounding systems to ensure I have a consistent ground throughout the car.
Over the weekend
of August 10th, I started digging into
all the wiring that had been added to the car to accommodate the various gauges,
controllers, alarm, and stereo gear, that have been added over time. And,
the more I dug, the more I didn't like what I was seeing.. a bunch of spaghetti.
Now, I am pretty good at wiring, and have not had any shorts, blown fuses, or
other problems (other than insufficient grounds) yet, I decided to redo
everything. So, I gutted all the non-factory wiring and am in the process
of redoing everything. So, with the front bumper cover off, the fender
liners out, along with the seats (F & R), center console and center console of
the dash... it's looking pretty barren.. I've also removed all the wiring for
the fuse-box which I relo'd to the hatch with the battery; and, the fuse-box will make
a return trip back to under the hood near its original location. Over the past
few weeks, I've scoured JC Whitney, Home Depot, a couple stereo shops, and a
couple electronic parts outlets here in Houston for all the components I need to
rebuilt the power and ground systems the we they need to be done.
SUCCESS!! I started the engine with the new wiring in place
on Sunday, Sept 14, and found I had 14.5v pretty-much all the time with the
engine running and the headlights on.
- added two independent and individually
adjustable switches to the clutch pedal - one switch each for flat-shift and
- rewired the fuel pump with 12 ga. wire, adding
a relay in the rear hatch such that the Autronic SMC trips the relay which
then applies +12v power to the fuel pump directly from the battery
power distribution unit (PDU) - This has been fabricated and close to
Greddy gauge controllers in center console.
- mounted the
Autometer ProComp warning lights
on the lower gauge pod on the A-pillar
- fabricated mounts in the front left corner of
the engine compartment for a series of relays. Although I'm planning
to use only four relays at present (two for fans, one each for nitrous and IC
spray), the mount will support up to eight relays. And, for those who
wonder, the zip-ties are temporary; I'll permanently pop-rivet the relays to
the mount when I'm through fabricating and wiring them into their respective
fabricated a new mount
for the fuse-box so I can relocated it from the hatch to the front-left corner of
the engine compartment.
- fabricated an
intermediate harness which
connects the Autronic SMC to the new primary
- relocated the factory
to the front-left corner of the engine compartment.
- fabricated a
system for under the hood.. connected up the twin coil pack, both igniters,
throttle-body and both factory under-hood ground points. All are connected via
8 ga. stereo power cable to a 3" x 1" strip of copper that is mounted on a
steel brace just off the alternator mount. This copper strip has a 2 ga
wire running to a second center ground point located under the rear seat,
which is a connect point for various 8 ga ground cables from the stereo amps
and a couple factory ground points under the dash. This 2nd ground point is
then connected to the (-) side of the battery with another section of 2 ga.
- fabricated a
nice bracket for a small
switch that will make contact at 95-100% throttle. NOTE: I was going to
use this as part of the nitrous activation system but have since learned that
I can allow the Autronic SMC utilize throttle position in its control of
nitrous activation. So, I no longer need to this switch...Fun
rewired alternator output with
2 ga. wire that runs across the front of the car, under the ac condenser,
to the 1 ga cable that connects to the starter. This will ensure a good
path of current flow to the battery.
- rewired alternator inputs
- rewired a/c compressor circuit
- rewired pre- and post-IC temp senders
a single harness to the stock
factory fan temp switch (located in the bottom tank), the n/b O2 sensor, and
the MR2T oil level switch
- ran additional wires to an adjustable pressure
switch that will be used in conjunction with the Autronic SMC to control
nitrous activation. This pressure sender will trigger nitrous below a
certain level of boost, at which point nitrous flow will terminate.
- rewired existing oil pressure, oil temp, engine temp,
and trans temp gauges, and installed new wiring for oil pressure and
engine temp warnings
- I've made several
modifications to both the
engine wiring harness and the
Autronic SMC wiring pigtail. Wires that are no longer needed were
removed while other necessary wires were added.
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