Please describe your symtoms .
wont crank, or cranks but starts and stops , or starts ok but has no power.
what is it?
with out these facts, anything could be bad.
first , there is no carb. on a 91 it's TBI.
assuming you are in the Nothern Americans or Canada.
http://www.suzuki-forums.com/attachm...s-efi-jh-w.jpg
with a volt meter and the above you can do magic.
this is the best simplified schematic they put out on this car.
yes, there are relays under the dash.
one is called main (id23), if bad you get,no spark , no nothing, even ecu will be dead !
the other is Fuel pump relay. id 24 , pump is 22 on dwg.
Injection diagnosis;
is your check engine light ON?
yes, what is the code ? ask for instructions here.
no, ? then.
are you are sure your fuel pump is good and is active and the fuel pump relay is energized by the ECU. The ECU actually controls the fuel pump. Pin B16 and B1 of ECU. ( not the Ignition sw like on american cars)
do you have good fuel pressure ?
to test you need a pressure gage: and training so you dont catch fire.
Ignition on, no start, pressure is 34-39psi , after start it will be 24-30psi ( as regulator energizes)
(do not open a gas line unless you know how to bleed it, safely, please)
step 2:
with ohm meter measure, the injector, at the ECU.
pull ECU connector and measure from, B8 to B17. < RX1 scale of meter
it will read 0.8 to 1.8 ohms, if yes injector is correct and not shorted or open and the wires are good end to end.
if OK then:
A tech would check the pulse on both legs of the injector
if pulse is bad then get a new ECU.
what is the car not doing correct.
starting, running or running under load bad?
if car doenst start can you get it to start with can-o-instant-start or just pour 1 teaspoon (no more) down the throat of TB.
if it starts and goes veroommmm and dies, then you have spare and the main relay is good.
Compression, ignition, timing and injection, bingo start.