1990 Geo Tracker 4x4 Manual ECU 60A31 Repair

[fixkick]

Hi there..I'd like to add to this thread..I've got 2 1990 tracker tin top 4x4 5 spds...
They're twins except for chevy vs gmc badges...zukes all.
that is correct, in N. America, only, and but not smog, , for example the canada one may not have EGR monitors, but has EGR.
and 89s had carbs offered in N.America. and in all other non usa countries, had carbs many many years latter, in fact have 4 class engine types. world wide.
what country you are in matters. if you say GEO, that lands you in N.America, (90%) if you say same with sidekick but not Vitara....



My daily driver started randomly quitting at speed-cut right out- (the 1990 usa car , the distributor makes spark all by its self , so..... sparks first and only there , plugs/wire/distrib cap..rotor,cap.ignitor,VR pickup and coil and internal advancing weights, )
elaborate the cut out.... this matters, and can you end the cut out with your right foot, less, more foot pumping or?

so I'd pull over wait,restart and carry on ...till it happened again.

This makes things difficult to diagnose. Sure it is if spark is intermittent, ever set the VR Gap?

Finally she quit and wouldn't restart.Towed home.Now I can diagnose...good spark,means good coil and pickups. Now fuel..Pull return line and air horn from TB and crank over while looking at injector..no fuel from injector but tons thru return eliminates fuel pump,filter and lines to TB so injector or ecu.

Rarely see injector fails except for o-rings so I go with ecu as cause..change it out with known good unit from my twin and voila!!
but the screens on same clogged, 10 micron.
So I just loved this post about cap change outs with pics.....
most of these ECu all fail, every one , once, do to those junky, Rubicon black caps.

I would like to know how "the shop" hot wired said injector with a toggle? (this is why the injectors drives burn up, changed many out my self)
hotwiring any ECU is evil , stop them and win.... my page on ECU warns of hotwiring ecu ,like 10 times...
How is this done without burning it up? Could be a useful trick for those of us that find ourselves in the back of beyond sometimes.

Do you have have the 90, ecu schematic? I have 91 up.
but not 90... the 91 up blows up hot wired.
the samurai had an external injector resistor block, that can fail. ours dont have that. on any year.
here is ours.....
my work.
http://www.fixkick.com/ECU/injector-drivers.jpg


now you draw yours. and we can talk facts.
this is what 91+ does. hot wired.
if you hot wire the red wire, you burn up the injector coil and maybe Q102, if the injector burns and shorts, Q102 is burned to a crisp,
if you hot wire the yellow wire, q102 blows up and or R225.
in all cases if the injector services this event (hotwiring) the injector pulse widths will be wrong, controlled injection ends. because the 2 transistors have different pulse widths and the combined sets correct injection rates

on some (rumors only , early ecu) the Q101 is just a resistor, and Q102 does all pulsing, just like all MPI do.....sans resistors
in this case, only, (rumors suck) but one could hot wire the resistor, but if you did , and the rumor was true, then the lower transistor and injector overheats
how can this help anyone, for sure a $400+rebuilt ECU is no fun event.
the injectors is 1 ohm, at 12v that is Power = V squared divided by R. (ohms laws) 12 x12 /1 or 144/1 or 144w... the math.
12amps flows, huge current hot-wiring this. I = E/R , 12/1 is 12.
144 watts flows, touch your finger to a 100w light bulb , imagine that burning heat in side the injector or that transistor.
hopeless,
just because 12vdc seems safe its not, not for hotwiring parts. with no real knowledge of what's there.

it is a fact all of these ecu's use a cooling PWM pulse to keep that 1 ohm injector cool.
this is documented, I have the wave forms for it.
the there are 2 signals there, the cooling part, and the injection rate parts.
if you mess with either , the fueling will fail. hard.



hot wired damages if repaired many times on many ECU.

Injector driver 1
injector driver 2
+5vdc supply blows up the PCB trace to h3LL,
fuel pump relay driver blown to up
all VSV drivers blown up.

how ever the RED injector wires harness wire, if it lands (by any means) on ground, Q101 burns up. seen many. all are easy fix, if you have my fix it page.
but ive never had a 60a ECU in my shop. to fix. lots of 56B (91+)
send me one, and will do the schematic and may fix it for free.

here is my 56b page showing all DRIVERS, drivers and CAP are what most ECU fail for,... most.

see this.
http://www.fixkick.com/ECU/transistors.html

that shows all 56b main failures parts. on one page

i dont have a page on 60a, (car is rare in most States) see real p/n of parts and true makers name....


the 89/90 has no spark generation in the ECU at all, its a FUEL only ECU.
the 89/90s are not the same world wide, not a all, vast differences.
the 89/90s do monitor only spark, and if it sees spark die, it cuts fuel ,as do all ECU on all cars made by law. crash and burn rules.

http://www.fixkick.com/ECU/ECU.html

nut shell.
ecu tests (on my test jig on the bench)
1: if there is (measure it) 5vdc on that 5v pin, if not fix that first.
2: check all drivers on ECU. oops. hotwiring H3LL i bet...
3: new caps first, if they are black caps, and original they are junk, if some one used fleabay caps from china. most are junk, use Nichicon from japan. those dont fail. with the high temp option, shown on my page,

do no us NO NAME caps, or any you can not pronounce. like (som-ting-wong)? and the like, they are junk with cloned electrolytes inside,
Nichicon is a world leader, there are others, ask.


Keep in mind, at all times many of the parts inside all these ECU's , the parts are not made now. "discontinued"
so we find NOS parts, (some are not found at all)
or we cannibalize another ECU, making 1 of 2.
same with speedo clusters, in spades..


yes, we dont change out ECU untill last. due to 2 reasons.
1: most ecu dont fail. if got new caps and no hotwiring bs. they dont fail.
2: the rebuilt is $400
3: the other parts need to be checked first. ECU inputs, and spark, and fuel pressure , all are first .
4: and last but really a #! fact, if you put a new ECU in a car with shorted outputs, BAM, 2 bad ECUs. so.,... that cant be fun...


wish i knew if car was bogging cut out , (foot pedal right, was dead,)
or its was violent misfire, engine shakes, you can hear it, feel it .???
this is key to finding cause, as CUTs out , is not enough information to diagnose any engine ; the technician needs to drive it.
if it misfires parked, we do that first. easy fix. that.
or bogs park as I roll the TV.