93 Tracker ECU woes (no power to injector)

[mechoption]

Got a 93 Geo Tracker. After much troubleshooting for no start, found injector not working as not receiving power from ECU. Bypassed (through 5A fuse) power to injector, and car runs no problem. Took out ECU, see photos attached or posted here photos.

Is that capacitor (C48) involved in driving the 12V to injector?
Is it ok to just run a new 12V line to injector (through 5A fuse)?
Can that cap be replaced (way beyond my skillz).
Anything else that could stop 12V to injector?

[fixkick]

so its a 93 what? 8v or 16v engine>
the caps leak , all do , if not changed out. all caps this old leak or just dry out
never hot wire any injector, sure it runs but like crap, its done at junk yards, and for this car used only to pull stumps. but not for series driving, and not getting 15mpg gas mileage.

All caps there are INVOLVED. not one is uninvolved, they are filters, and if bad you get noise, and noise causes data errors, and CHAOS.
any cap here can be changes out by any tech, all techs electronics do this all the time , the parts last about 20 years, caps, they are the weakest part of aNY ECU made.

ok second photos shows 56Bxx ECU, 8valve G16a engine
my guess is you hot wire the red injector wire to the TBI, (nasty trick that)
if you keep at it you burn up that poor, 1ohm injector there. that will cost you.

if the red wire is dead, then its cut or transistors number Q101, 2SB1020
its all documented here,
http://www.fixkick.com/ECU/transistors.html

and here
http://www.fixkick.com/ECU/ECU-8v.html

what can happen is the red wire ground to the body, (called a short)
and blows Q101 to kingdom come, a $2 transistor any tech on earth can change, its not SMD here, its good old easy to change parts, old skool , solder lead feed trough parts. super easy.
take a new ECU on a new car and parts only an ANT CAN SEE, hard.

find a tech
find a ham radio guy that is old ,new kids dont make things today so, only old guys know this.
tracker is mostly USA or Canada, and we have CARDONE
http://www.cardone.com/find-parts/vehicl...&year=1993
and they are #1 in ECU repairs here. bar none.
see engine control computers,.
then ask for a local stocking store, this link is the MAKER and they DO NOT SELL DIRECT TO THE PUBLICK
all stores in my town can buy this REFURB.

there are just 2, one is A/t other is M/t , the A/t car must HAVE A/T ECu or cant shift.

[fixkick]

replace that corner cap its NO GOOD and when NO GOOD the ECU goes NUTS>
it boots over and over and over, in a total CHAOS way.
mouser.com sells them, need a PN? once ECU is on a shop bench, its like 15min work to fix it.
the transistor takes me 1hr work , getting the heat sink right and HS grease too. right. (simple but tedious it is this 1 transistor.)
why not fix the cap and undo the hack an try it.

all caps on this car (electrolytic) must be changed 1 time. then then again 20 years from now, i use a top brand that many last 50% longer.? Nichicon ! made in Japan and is SUPER GOOD !

[mechoption]

Agreed ! Found a local electronics guy to replace all caps and transistors (well, he'll test the transistors first, as physically they look good), including C48 which is a tiny surface mount fellow. So no more hot wiring. Will be an interesting moment of truth when I reconnect fixed ECU and turn key !

BUT, I still don't understand how hot wiring through a fuse to the injector can damage it? If injector is 1 ohm and I'm feeding 12V through 5A fuse, then I can never reach the peak current of 12A that would occur if I maintained a constant 12 V across the injector, as the fuse would blow first, and yet it doesn't? Seeing as though ECU grounds the negative side of injector to fire it, how can injector tell if the 12V came from ECU or other source? What am I missing? [my electronics knowledge fairly primitive !]. My thought was ECU provides positive so that it can decide not to if it detects some other issue in the engine (so I risk some other issues, but not injector damage, but I don't know what)

[fixkick]

THOSE 2 transistors , for the injectors are still sold.
a curve tracer works best on those, but nobody has one, today.

what does hotwing mean, it means removing the wire and putting 12vdc there, all the time.
this ends the pulsing on that line, dead. now is 12vdc.
if you meant adding a fuse inline, well that is 100% ok an smart, it saves the ECU when the injector or wire shorts, done many times here.

both the red and yellow wires to injector are pulsed of you bypass that.
12vdc to red
or 0v ground to yell.
the pulses end, now, and MPG goes to 15mpg or worse, the ECU can not control injections if you wreck those pulses, not only that they cool the injector but if lucky that fuse does protect the ECU, weve used 7amps too. ok.


this car is very unique, it does not work like any MPI cars made on earth (PNP, or NPN fired, one wire is 12vdc ignition and it fires to ground)
nor most TBI. but not this car, it runs dual fired wires.

this ecu fires both wires,

here is the scope readings that tell the full story

here is the cooling method used

http://www.fixkick.com/INJECTORS/TBI-pwm-wave1%20.jpg
12v at 1 ohm is 12 amp (I= E/R) but that current is only for 3mS , 3/1000th of a second and is also with cooling pulses to lower heat more.....
http://www.fixkick.com/INJECTORS/TBI-pwm-wave1%20.jpg


now red and yellow


red to ground
http://www.fixkick.com/INJECTORS/INJ-red-gnd-1w.jpg

yellow to ground
http://www.fixkick.com/INJECTORS/INJ-yel-to-gnd-w1.jpg

and transverss (red to yellow)
http://www.fixkick.com/INJECTORS/INJ-red-to-yel-w1.jpg


if not like this, the ECu gets all confused, due to being out of control, it must do 2 things , inject correctly and keep it cool, both.