Samurai TBI | No Injector Pulse

[fixkick]

our  8v is not like that at all . TBI/SPI.  100% unique to this car  TBI unlike any other TBI on earth in fact.  2 rail driver, see that, sing UNIQUE.
I test mine using a scope
nobody sells used or better reburb samurai ECU now, for sure not suzuki.
all these old ecu love to fail for top reason bad electrolytic caps,  the VRMs too go nuts with noise on the inputs to the  VRM voltage regulators models.
there are many failures beside this.
1: all inputs to ECU must not be wrong for sure  CMP and for sure TPS TP pin (1v good not 3.5v up) TPS idle switch pin at 0v not 5vdc.
2: caps not bad.
3: injector not shorted or  its 2 wires. nor open wires. nor shorted to ground.
4: r225 (different id on sammi) not open. 
5: snubber D112 not open or shorted, if open back EMF (inductive kickback) signal kills Q102 dead.
6: both transistors must be good and pass super beta (hFE) tests.
7: both transistors must not be metal backed, or C is shorted to metal heat sink and boom, dead.

many cars these parts are blown to hell buy doing hotwired HaCKS. (AND NO CPU SOLD NOW.. IS WHY)


this is sidekick 91 -95 , not sammi  ecu. but is close. names different. on ID.

[fixkick]

OK this car is TBI and only this car has this class of TBI , and not even like any MPI 4 injector or 40year old chevys with TBI not the same.
no shops know this car this TBI nor do they even remember OBD1, and the lack of scan tools on this car, suzuku sucks here. that rule.

This TBI drives both sides of the Injector (2 transistors)
and both must be good or the engine dies, or floods,
the work as team to get the PWM correct and  nether transistor is optional.

it is not  just one transistor per injector like 99.9999% of all cars on the road it is 100% unique to this suzuki. the TECH.

the transistors fail for many reasons, here is list. to make it simple. (more) (all other input pins to ECU not wrong)

• injector is shorted (coil)
  
• wires shorted to injector
  
• alternator went mad, (reg) and hit 20+vdc boom and wrecks transistors lots.
  
• overheated,  transistors,
  
• overloaded, see alternator or shorts.
  
• ESD damage (bad handling)
  
• lightening hit car, boom. random things dead.
  
• ECU came from other car that was stressed badly there, (history matters)
  
• transistor loose on heatsink.
  
• transistor thermal grease old and cracked, causing overheating of same.
  
• wrong transistor put in and shorted Collector to ground then causing other transistor to overheat and engine wants to flood badly.
  
• R225 open only so transistor can not work at all.
  
• some one wired in a silly ALARM box to car or  omg remote start box to ECU and blew up very rare parts. here.
  
• some one (not you) hotwired the injector. (seen this vast times,)
  
• I hope I got them all.  but there is on more (luck bad, age failure or pure  entropy failures or part was weak to start.)
  

[d8nk]

Great condensed answer and I am confident I am at the end where I need to replace positive (red) driver transistors. That one does not test out properly with a DMM either. I did order two in case I fix it and it fries again. Something had to of caused it. So first thing make sure it works, second go enjoy my top and doors off in the last bit of summer!!

I'll update once parts arrive and I have time to dive in again. Thanks a ton your time!!

[d8nk]

Great condensed answer and I am confident I am at the end where I need to replace positive (red) driver transistors. That one does not test out properly with a DMM either. I did order two in case I fix it and it fries again. Something had to of caused it. So first thing make sure it works, second go enjoy my top and doors off in the last bit of summer!!

I'll update once parts arrive and I have time to dive in again. Thanks a ton your time!!

Ok I missed a bunch of what you wrote on page two, all I can say is WOW. You are so far above my head on this I can't even understand most of what you wrote. I am no electrical engineer   so I appreciate the summary. I never tried shorting (killing) the injector and doubt anyone before had either I have owned it for about 5 years and it has always run perfect. It is unfortunate that these Samurai ECUs are impossible to find. I hope I can fix mine.

I am curious what killed it in the first place. My suspicion would be a short in the injector, just a gut feeling as I have testing continuity on most the wires and checked against ground looking for shorts. Nothing found. Like I said before I will update when I get parts. Thanks again for all you effort and leaving this bomb of knowledge for someone to find down the road!

[fixkick]

Great condensed answer and I am confident I am at the end where I need to replace positive (red) driver transistors. That one does not test out properly with a DMM either. I did order two in case I fix it and it fries again. Something had to of caused it. So first thing make sure it works, second go enjoy my top and doors off in the last bit of summer!!

I'll update once parts arrive and I have time to dive in again. Thanks a ton your time!!

Ok I missed a bunch of what you wrote on page two, all I can say is WOW. You are so far above my head on this I can't even understand most of what you wrote. I am no electrical engineer   so I appreciate the summary. I never tried shorting (killing) the injector and doubt anyone before had either I have owned it for about 5 years and it has always run perfect. It is unfortunate that these Samurai ECUs are impossible to find. I hope I can fix mine.

I am curious what killed it in the first place. My suspicion would be a short in the injector, just a gut feeling as I have testing continuity on most the wires and checked against ground looking for shorts. Nothing found. Like I said before I will update when I get parts. Thanks again for all you effort and leaving this bomb of knowledge for someone to find down the road!

• sure the injector shorted is bad deal.
  
• wires to it shorted end to end.
  
• alternator went mad (reg) and sent out 20vdc or more blowing up or causing injury to transistors. seen this vast times. even blowing up car radio.
  
• Transistor over heated or heat sink fails , screw loose there or TIM compound failure there. thermal grease died out after 30 years.~~~
  
• bad luck (entropy) aka, OLD AGE failures, no parts here last forever.
  

I sure hope it is just one bad transistor.
that be an easy fix.

I always had spare ECUs from mine,  some are impossible to find now, and driving far from home and that fails , no cure.

[fixkick]

something must have caused it , yes that is wise thinking
but not true, always,
all parts made by man fail
the hotter running parts love to fails first. power transistors top this list. and CAPS are top of top of list always , RECAP it?)
bad luck
entropy.
age.
none of those are someone.
top failures in this ECU are all electrolytic caps failed,

the ECU is really microcontroller, there,
and has VRM voltage regulators, none are LDO rated.
the caps go bad (dead zero uF) and now the regulator goes NUTS, on and off line over and over.
see this vast times even all relays to ECU clacking like mad.
so the CPU inside never stays booted up, it just reboots endlessly and in this mode the injector never goes on LINE.
#1 all time classic failure and covered in my bad ECU page. fully, leaking acid caps and all,
a cap that looks bad is
a cap that looks ok sure can be bad even dried out inside where you can not see.

what happens above is the CPU inside resets endlessly,do to BAD POWER regulation.
power is king if power is weak or full of noise, you have very very serious problem in electronics, for sure inside any ECU.

I test my transistors and the are good (example)
i then scope the base drive of each transistor with my scope and scope signal is dead or wild crazy spikes.
i then see power to the chips 5vdc is full of noise.
bad power it is.
recap it now.

[fixkick]

even old age cause all parts to fail.
stress and age is the simple answer.
over time.
I used to run factory testing (ATE)
and we tested life spans using heat and fast cycling at 100C temps.
Mil testing was this.
military grade.
all parts made have bell curve, aka a bath tub shaped curve for life.
(curve shows;;;;;;early fails, long life then end of life fails.)
all parts. (electronic)
caps are 10 to 20 years rated, why think yours are good.> ?

the caps on this car love to;
leak
explode. crack, spit leak acid, go dry, even make tiny volcano's on the side of case, or rubber plug on bottom blows out or Bulges, the tops on some have X cross that cracks (to stop exploding trick)
the only way to know is test them with a ESR or Cap meter, best test is REMOVED. they are polarzed, never connect them up backwards, minus to minus it.
or simply replace them for $5

[d8nk]

I know a lot has been typed but the first thing I did when I was getting a dead NOID test (and testing everything else you have written about) was replaced the caps. They are all new now. I didn't have any visual signs of them being bad but read so much about that being the first thing to go bad on these ECU that I just did that right away. That is why I am trying to narrow it down. 

On a sad note the Match a Knob place has not shipped my transistors yet... I have to call them tomorrow and see what is going on. It has been a week now.

[d8nk]

Well Match A Knob never even replied to any requests so I requested a refund from PayPal. I ordered some "ebay" transistors. They just arrived. Will update once I get a chance to test them and hopefully install and give good news of it running again!

[fixkick]

Well Match A Knob never even replied to any requests so I requested a refund from PayPal. I ordered some "ebay" transistors. They just arrived. Will update once I get a chance to test them and hopefully install and give good news of it running again!

match knob is  "pin ball machine"  parts seller from 2007,  13 year old links they may be offline forever or KUNG-FLU down.

just use google or ebay
those are real Japanese made transistors, not USA brands.  so takes a bit of work to find.

but can be found,  ive even ordered from 2 sources at same time so down time is less.... on car.

i presume you read the numbers off the transistor cases right.?
2SC1234 (fake example)
is marked C1234
see?
2SA, 2SB,2SC are common . prefixes from japan. it is there numbering system only.  
good luck to you.

yes new caps are wise.  , they can dry out and no outward signs, but all fail ESR tests if tested and are bad.