I have an aprillia Sr 50 2008 model and its got good compression great spark and fuel but it won't start and it floods my engine don't have a clue what to do

That is not bad compression, you have something else wrong. IS the fuel good? What is the timing?

Is the spark plug black with soot?A black sooty plug will not fire most of the time.

it's not a ford, (park that ford manual now)
short answer, only in your dreams....

got 12vdc to the pump? cranking?
got spec fuel pressure cranking and running?
that matters
as does not checking spark first
the PCM cuts fuel if spark is dead, (3 ways)
1-cmp dead
2-ckp dead
3-ignitor dead.
3 ways. and all 3 stop crash and burn, as seen on TV.


why not post symptoms, then ask for how to diagnose this problem.
instead of guessing wrong.
why guess?
the tests are easy , ask how.
if you dont have tools its mostly just flaying about.

no start 101:? (pasted in , vast times)
Cranks over fast, but will not start. (posted , 100 times now....)
Mr. Otto Cycle engines,.... (spark/gasoline/petrol)
no start or stalls, and will not start now.
There are over 50 causes. even a simple rusty fuse. (or worst hair line cracked)
Head lights work and not dim? CLuster lights all work like new car?
We use PHYSICS to find cause. Never guessing. (meters , gauges and 1 scan tool)
About 1 to 10 tests.

1: Fuses good?, all EFI and spark fuses?????not just looks GOOD (test them)
2: Check engine lamp glows key on, ? if not? see #1
3: I crank engine, it cranks fast. but do you have spark on all cylinders. (not just 1 , all)
4: Is spark timed right, not 25 degree's retarded, if retarded illegally, that is the cam drive slipped. (belt or chain,no matter)
(5min with a timing light and wow, the bad ignored belt, is discovered)
The cam belt is a 60k miles service, point on most cars. (with belts) so.....
5: if you find spark is dead on any cylinders and is not bad spark parts (wires,cap/rotor/plugs)
I then use a scan tool cranking and see P03xx DTC errors. P340s or P355s cam/crank sensor dead.
or if pre-1996 cars in USA, we use the 2 cent paper clip, diagnostic jumper clip, to find DTC errors.
DTC means "Diagnostic Trouble codes"
6: spark is good on all, now.... note my order here???? not gue$$ing, just testing,,,,,,
so we then use a can of "test fuel" now. 100 years we do this... it's a not new idea or magic.
watch Scotty do this here.
https://www.youtube.com/watch?v=064Ilsz8Fzg&NR=1&feature=fvwp

Does it run on test fuel.?
NO. bad engine. check compression, 150psi min. times all cylinders, not just one.
Engine ok, but spark is bad, will cause test fuel test to fail.
YES? runs for 3 seconds now, then you lost fueling. (congrats getting this far !)
Keep in mind all EFI gas engines, the brain cuts fuel if it sees 3 lost spark issues.
"CMP dead,CKP dead,Ignitor dead" to prevent fires. so not scanning the PCM you will never find the problem.
What to test next is a toss coin deal.
NO DTC errors, i then whip out my trusty fuel pressure gauge, cost all of $20bucks (investment grade it is with pay back !)
check fuel pressure next. it must be in SPEC range, as this is NO CARB car. it's EFI.
EFI means Electroinic fuel injected.
I'll not show all fueling tests , that is 10 pages of text, or read a ASE book on topic.

but... in short....

Fueling:
got 12vdc to the pump cranking?
do you? (any $10 voltmeter made works for this test.... or better)
you need to crank it to prove pump is dead... on half 1/2 the cars made.
we do all, that way, so that we don't get confused or wonder how EFI logic works.
"programming varies by that in the ECU" Some ECU/PCM had reflashes that upgrade this LOGIC.
The Suzuki J18 is a classic example of change. (must crank, just like 1989 cars)
If fuel pressure is low, the injection rates will HOPELESS.
if fuel pressure is crazy high like 60psi, the engine will flood hopelessly.
our engine here runs 30PSI.
we can do injector leakdown rates and balance test. and for sure im not typing that out...
end.

and last.
here is the USA page for Suzuki books
note how Liana is missing.
we dont have it.
https://suzukipitstopplus.com/Category/3-suzuki-service-manuals.aspx

next time post your country so we can give you answers based on how your car is made , not ours.

there is the list , and correct order that always works.
1: fuses. good?
2: 12vdc to all EFI parts (battery charged? at 12.6vdc? rested)
use a voltmeter, no guessing... and the VM dont lie.
3: good compression, on all cylinders. 150psi w.o.t
if all are real low the cam belt/chain slipped. (generic post)
4: good spark, the ECU cuts fuel ifs spark is gone, so spark
on gas engines, is #4. i check timing to see if cam slipped.
5: good fueling. (too much or too little, it will not start)
i check for flooding with spark plug tip checks, soaking wet is flooding.
dry is lost fuel, try test fuel check now, (spray fuel)
if flooded do the super secret unflood test in the operators guide.
SS-= cranking with wide open throttle.

i bet its running now.

skipping 60k mile tune up's will cause no starts
as will bad fuel.

engine failed before pump, or after.. confused i am.

no matter, all gas engines work same. (in the global sense)
got spark?
the EFI cuts fuel if NO SPARK , by design (PCM brain logic programming) it tries hard to make that happen. (fire safety)

the rules for all otto cycle engines, in order.
1: GOOD compression on all cylinders, 150psi or more.
2: good spark on all cylinders. and timing. (its fixed time , year 2007)
3: good fueling,, not lean, not rich or flooding
the tests are easy, do you want to test or guess?

pretend that #1 is ok, many do. but pretend.
do not jump to #3, as no otto cycle engine runs with dead spark.

if flooded and spark is good, using a test spark pull.
use super secret WOT cranking, wide open throttle, this CUTS Fuel
on all cars, to clear a flood. its in the opr, guide that, on all cars.

Be more explicit.
How the spark plugs looks like? Are them black?

great clue. first of 1000s.
no starts can be:
Ill not guess, ill presume you want to find the part and not spend $1000 on useless guessed parts....

100 years this is true. in macro form.
1: lost electric power to EFI parts.12v( bad fuses)
2: bad engine. lost compression ( a tool)
3: lost spark (tune ups never done) a test. you test spark at each plug.
4: bad fueling, (flooding or starving for fuel) 1 simple test.

here is scotty doing just this. (he knows the above macro)
http://www.youtube.com/watch?v=064Ilsz8Fzg&NR=1&feature=fvwp

The engine can't run without compression in the cylinders. The plug will still spark, but without a compressed air/fuel mixture to burn and power the cylinder down, the starter will just keep spinning the engine over, cranking forever and not starting.
Check if your timing belts are good and not broke. Cylinder compression is dependent on good piston rings, intake and exhaust valves that open and close at right times and that seal good when closed, and a head gasket that seals up the cylinder from leaks where compression could blow into the water passages, or oil passages, or to outside of engine.
If the timing belts are good, a leak-down test of each cylinder will pinpoint where compression is lost.
Good luck with the Sube, great cars, great engines, but the head gaskets are a common problem.

what engine, state engine size and country.
there can only be 3 ways, to fail.
bad engine (low compresssion, us the $20 tool at WOT and see over 170psi.
Bad spark
bad fueling.
just because spark coils (COPS?) work on other car , dont mean much.
what counts is your car , its a system.
the cops, have fast 5mS pulse when firing, you using a scope to see that?
Im so curious, why not to the time old test, use a real spark plug
attached to the COP end, spark plug shell grounded to engine metal
and crank, is spark good x4? or x6 if V6 (engine NOT STATED)
is it? then spark is good, leaving fueling.
do not touch the spark plug cranking, it can hit 100,000 volts.
I use a ground strap on the spark plug casing, hands free, or you can be hurt bad, by the spark or when you jump and cut arm backing off
on cars that flood, is it flooding?
I found my engine compression good, then found all 4 sparks fire good.
so i pull the fuel pump relay. killing fueling.
i then use "test fuel" to start engine (again, text book tests)
I use the new CRC brand of test fuel with top end oiling.
i spray it in the plenum, and it starts.
if the spark plugs are bad, (part oftune it up)
it may not start if flooded,
use WOT at the throttle (cuts fuel) and start any flooded engine.
if the spark tips are black and stink of raw fuel (wet with fuel)
that means flooding.
pull the fuel pump relay ,test fuel runs for 3 seconds. each time.
3 second spray max. each time.
if that works out, then find reason for flooding if flooding.
if not flooding, you find dry sparks.
then trouble shoot no fuel.
fuel pressure not near 30 PS?
fuel pressure too high say, 60, it will flood for ever.
there are only 3 tests.
and 4 counting wet /dry sparks.
the tests done, will put you on the correct path every time.
no guessing, no swapping parts to other cars.

When en engine won't start, there could be a number of things wrong. An engine requires air, fuel, and spark to start. You need to start by checking for spark. Take out one of the spark plugs and plug it back into the wire. Have somebody else turn the key while you hold the plug up to something metal on the engine, right next to the spark plug hole will be fine. You should see a bright blue spark, if you don't then you probably need to replace the spark plugs. You can do this same thing with any of the spark plugs. If you don't have spark on any of the plugs, get back with me and we'll go from there.