95 JX Susuki sidekick skipping, dumping fuel

[kina073]

Hi, my suzuki sidekick is skipping and dumping fuel, changed computer..new fuel injector, what do we need to check next? any ideas? Thanks.

[jtgh]

here is my huge list for dumpers.

Why-engine-flooding?

skipping = missing.
explain all it does good and bad, hot and cold.
is this an 8v or 16v engine.

tune up?

hard starting cold
hard starting hot.
too high or low idle , hot or cold engine.?

Start hard, floods and when does start it is missing, misfiring , and smells of unburnt raw gas with black clouds out the tail pipe?
if i guessed correct there, does it then run perfect after fully warming up.?

the ecu has many modes,
cold start, warm up, hot running and cranking.
all quite different.(in ecu brain)

if car is tuned up and has good compresion.
checking fuel pressure is a good idea.
and checking the ECT.

does engine get full warm , and arrive at 180F ?

[kina073]

Thanks...it's a 16 valve. Missing in #1 cyc only. Does not change hot or cold. This is driving my hubby nuts. It's like the fuel injector is stuck open. Is it possible that its a wire going to fuel injector? I don't let it run to long because fuel gets into oil. Thanks.

[jtgh]

you need to put a NOID lamp on Injector 1
if it dont flash , ecu or wires bad to injector 1.
on MPI engine, 1 wire is 12vcd other is injector driver transistor in ECU.

i have pn for the ecu transistor and they can be had.

if lamp glows solid then injector is being gated on full time.
shorted driver line to ecu.
or bad ecu
if being pulsed like it should then the injector is stuck open.

coil resistance is 12 ohms. on injector.

cheers.

[kina073]

How do you check the injector with ohm reader. Want to make sure we do this correctly. We were told to check wire reading at injector end and ecu. Thanks for all of your help.

[jtgh]

correcto

there are a few tests.
ohm meter. put meter on low range connect it to the injector.
it will read very near 12 ohms if not bad. it can read less or more ,or open.
open is infinity and will read just like not connected , holding probes to air .

always measure from 1 injector compared to others, if they all read the same, then all is well with the coils inside.
but that don't mean the injector is good.
it can be clogged or the pintle can be jammed. (no squits) sparks dry.

clogged is hardest to find.
jammed is easy too.

but before you do that make sure the DRIVER is working.
the driver is what we call the power transistor in the ECU that drives the Injector coil.
this transistor just acts as an electronic switch,
it grounds the injector to fire it.
the other side of all the injector coils are at 12v battery key on.
so the ECU fires them in parallel or in sequence depending on RPm.

ok, next is (easy to hard is best)
let do the NOID test.
whole 9 yards.
testing injection
or
http://carfix.stufftoread.com/NOID/91-noid-sf1.jpg

the first link shows the NOID lite kit, you can rent
the second is a simple light bulb that draws extremely low current and works perfectly, as a NOID lamp.

I unpugged my Injector conn. then plugged the lamp wires directly into the Injector conn on the Harness side (ecu drive side) then I crank and look, is it flashing.?
car starts, is it still flashing brightly.?

if it is flashing well, then most likely the ECU is GOOD

If not , the the ECU is bad , the ECU drive wire is bad, or there is no power to this injector feed plug, bad wires again. (fuse ain't blown, as the others work)

if you have NOID drive. then next get a mechanics stethoscope.

then listen to all injectors, if they all sound ok then #1 is clogged, at the front screens.
if the #1 is not clicking at all then the injector is jammed. (gunked up in side)

send it out to witchhunter.com for clean. $19 . ( fast too) near Seattle.

they can perform a miracle on these. (cept bad coils)

New injectors are serious bread.$$$

I presume you have checked compression on #1 and spark to #1 and both are good.

[TheZuke!]

My cousin Vinnie...

Actually, my brother-in-laws-brother, Lorenzo, suggested that
I check the fuel pressure regulator (FPR) about TheZuke! dumping
gas in the garage. (that was another thread here)

He said if the FPR gets stuck, it won't relieve the Fuel Pressure
in the injector rail when the engine gets shut off and then the
gas will trickle through an injector (and out of the EGR).

I need to get enough $$ to buy a replacement FPR for TheZuke!
Apparently the current one (a junkyard find) isn't working much
better than the one it replaced. (Yet Another Thread Here)

[jtgh]

i dont think so. sorry , blush.

zuke.
here is my take on that.
car running , pressure is at 29 psi ( and regulated by fpreg and vacuum and altitude)
you shut off engine.
pressure will drop slowly (not via injector , not 1 drop or it is bad)
It drop slowly ,by natural leakage of Freg (tiny) (that is, it will not leak below 24psi)
then from 24 down to zero psi , happens by the checkvalve in the fuel pump assembly.
in ONE minute , 21.3 psi is the min. pressure.
so its about 3 psi a minute natural leak down .

the injector coil is 0volts. at zero volts the spring in the injector hose a perfect seal.
IT must.
the only exception is FPR going bad and allowing 60psi or in there realm.
stuck closed FPR.

above is 8v spec.
16v :
subs.
92-95 FSM specifications on RAIL pressure.
1.6L KEYON-nostart ----35.6–42.7 psi 1.8L ----38.4–44.0 psi Static test:
1.6L Keyoff , min. 28.4 psi for one minute. (leak down spec) , Residual pressure test.
1.6L KeyON-start --- 29.8–37.0 psi 1.8L ---31.3–37.0 psi, Running pressure. <<<< THIS IS THE CRUCIAL TEST.
cheers and happy pumping.

[kina073]

OMG, it was the wire....guys!!! The wire from the injector to ecu has gone bad...jesus!

[jtgh]

a blessing.

good JOB !

no sending ECU in.

cheers.