Samurai TBI | No Injector Pulse

[fixkick]

Hello all, new to this forum but have been reading a ton, thx for all the info! 

Backstory: Driving along and suddenly engine died. Spark test - pass, Fuel pressure near 50 psi at intake, basic NOID test, failed. Replaced caps on ECU. Still no NOID pulse. Did more extensive testing, TPS good, injector at 1ohm, wiring good from ecu to harness at TBI. Here are where my questions begin.

Doing the pulse signal tests on positive side (red wire), I get no signal, key on dead, turning over no signal. 

Doing the test on negative side (yellow wire) I get no signal, key on dead, turning over dead. 

I'm pretty convinced one of the transistors is bad. Curious if there is an simple DMM test I can do on the transistors to determine if one is bad? If the plus side (red wire, B8, Q101) transistor is bad will this always kill the signal on negative side? Is it both work or both fail? 

Trying to do as much testing as I can before I go the route of replacing the transistors. Thanks for any input!

1992 Samurai TBI 8v
-80CXX ECU

before doing all that radical things to ECU , know that the injectors can cut fuel for other reasons.
I presume engine runs on test fuel and spark plugs dry? sure , no injections sure. but sparks good means test fuel works (hand sprayed in the air horn of TB)
The test fuel; test tells more things, ECU not dead, Engine timed ok, and runs on test fuel proves that easy. Timing belt not snapped, or spark or  cam timing way the hell off time. compression ok, if 80psi WOT the cam belt slipped 155 is par.

here is how the ECU logic works

FI and IGCOIL fuse not blown.

insert the diagnosic, jumper in the DLC jack.
key on CEL glows must,
and will flash code 12, good, code 41 or 42 means spark failure.

if yes crank the engine for 5 full seconds. release key
and see if code 41 or 42 show up now,  the long cranking lets the spark test run out. fully. or any other code related to TPS is bad.

injections are last things in the chain of logic to work.
first is the idle switch closed, at 0vdc. key on.
then TPS TP pin at 1v not 3 ,4 or 5vdc, if yes, the ECU goes to CUT FUEL mode this is UNFLOOD mode in the users guide called WOT cranking to unflood.
then all spark test both,  of them CMP not dead or missing or the coil feed back wire called tachometer not dead or missing.
if any of that fails, NO INJECTIONS are going to happen to keep As seen on TV crash and burn.
the ECU does not want you are car to burn up. injecting with bad spark.

that includes, intermittent spark of any kind. (code 41, code 42)

I do not see how both transistors can fail,  but the low side transistor must have pull up to test it. the injector 1ohm coil meets that need.



12vdc on all power pins of ECU and grounds. too.  Im sure they  are but to be full here yes.

I have never tested the ECU for  cut fuel if  only timing is way off, some cars in fact do that. for sure. mostly newer cars
dead spark or intermittant,  CMP not dead, coil brown wire not dead.
TPS at idle not WOT 5vdc. TP pin 1v, idle pin 0v.
are the top causes of lost injection, dead injector,
if you are lucky the key on test, for prime pulse at tip of injector horn off, seen to shoot very tiny fuel just keyon each time the 3 second rule happens.
key hear pump run 3sec, and this very tiny squirt happens. but not guaranteed, but if seen, is super good information if seen.

tell me more? this can be fixed easy based on tests.