97 Sidekick Sport 1.8L - CUTS OUT AT 1/4 THROTTLE

[fixkick]

what dont we know.?
well fuel pressure
nor if other DTCs are tripping, (not seen , live scans done hard driving and failing )
we take a car out and drive it aggressive up a hill . with the scan tool connected.
to get lean cylinders to misfire , it takes driving aggressive. (not fast speeds, but loading the engine hard over and over up a hill. you have hills? not in Kansas.
this is when the other DTC P030x codes can POP, now.
and if they did, it would speak load and clear with might be wrong.
engine lean or the other 20 year old boots bad.
since compression is ok, says the sparks bad or fueling.
try some Chevron Techron yet, in the tank additive, its got super strong benzene it it (the cheap stuff is junk at walfart, has only Stoddard solvents, useless that is)
to clean the injectors (its name is that)

misfire means lost combustion
misfire can happen too rich or too lean.
or bad spark, engine ok.

you are here asking how to test, right and not guess?

not in a shop hooked to scope and watching spark plasma , signals, all good shops can do that and see cause, of misfire
they can see the coil work, right (HV), that HV sizes and the plasma size tells them whats up. (or not)
its not coil if HV is ok, but can be bad boots, which bypasses spark plugs and the energy just jumps to the engine spark wells.

if the cylinders are lean or rich they can see that too "plasma size and shape".
(see HV here, that is good, as it he P for plasma. perfect)
http://www.jeepdied.com/scope%20views/hv-good1w.JPG

see that fuzzy line in the P, that is fuel burning, amazing no?

at home you dont have a scope or that $25 mag clamp, im using.
so can not know what's wrong, spark x4 or fuel mix wrong.
it's one or the other,
what the real question is, what costs more? guessing or 1hr shop time (diagnosis time, only)

The loss of power is a large list.
low fuel pressure (filter packed after 20 years??????)
spark misfire (a scoped test. shows this easy)
engine is good. seems so to me...
fueling wrong due to WEAK MAF sensor?, the PCM only tells you when its dead, never weak but P0171 lean, code, can happen.
When I was young , before blessed with tools, (fancy tools) I had shops use their SUN 300 ,(on up) to check for spark problems.
Some problems are not easy. (complex systems all are like that)
Some can never be found guessing, (id say 1/2) (like if you put in a bad part or its a wiring problem, or is 2 or 3 problems typically seen on most 90s cars.)

happy trails. and cheers and good luck.

[MtTrails]

Today I was checking the MAF sensor and as it was siting there idling, I noticed it started doing an intermittent mis-fire. I could hear it drop a cylinder now and the, stuttering of and on. No rhythm to it, just intermittent. The MAF Sensor check out good ranging from .55V at idle to 3.0V wide open. The only things I haven't checked are fuel pressure and injectors, my gauge should be here tomorrow.

[fixkick]

DOES ENGINE HAVE FULL POWER WIDE OPEN THROTTLE
OR DOES IT MISFIRE DOING THAT.?
if no elaborate
if yes does it buck

[fixkick]

and good engine bogs with lack of fuel
spark gone, causes violent engine power loss, (1 or more, even 1 is violent, its just 4 cylinders. not V12)
flooding can be less violent but the spark tips turn black. and cat over heats.
so there are some facts using almost no tools.

[fixkick]

misfire too,is power loss
but is violent..
I cant drive it and learn ALL That in 15min work.

[fixkick]

i lay odds bad spark
but am only correct 1/2 time not driving it.
I bet boots bad (sorry,no not #1)
after all ,if one is bad, all are, its a set if kept a set the age and die as a set.
pure physics that.
called HV breakdown.

that Duane video shows, him slowly and painfully moving a ground lead over the huge surface area of a boot.firing
math..
Pi. times Diameter. x lenght, = area and x4 boots, yah pain full long tedious test. and risk of nasty painful electric shock.

i can do it here, with my many test jigs and scope. and kitchen alum, foil wrapped on the boot.and then grounded foil.
using my HV generator device. on the bench.
if plasma test fails then boot is bad
Duane point i think is, not paying shop labor to do that. $200 labor to find a bad $15 boot>, is not wise in any shop.

on spark wires, external one can see them flash over, in the dark
or spray water mist on them and hear,it misfire, bad wires
but boots are burried. so..... a hard nut to test, for most folks, lacking a scope.

all goodshops have the spark testing scope, even shops in 1961 with SUN 300
today all scopes work with the dirt cheap probe.
we can see the plasma fail.
and why. the book on the tool shows all the examples and why it fails.l my advice, find any good ASE shop has real tools like this.

[fixkick]

as the song goes, what will be, will be..
no man can block fate, or pure raw physics.
in the end nature always wins.. entropy

Like the Mount Everest climber guide, guy said, the Mountain always wins, in the end.

[fetcher]

I read the whole thing again MtTrails wrote: "I washed the engine with a pressure washer, and after that is when I noticed it start missing".
I would guess something shorted out, or you still have water where it should not be.

[fixkick]

He offered no time line
did it run for years misfiring, no idea.
the spark well fill with water on all 16valve G16b as does the J18,j20 and up and all suzuk's made with cop coils
we all know this, expect it,, water conducts. at 30,000 volts (dirty watter)
also old COP boots act as sponges and the short, they all do this, its now new, knowledge. even spark wires do that.
some take a long long time to dry out,other never recover (the boots)
those bad boot , form carbon, some seen other not. This problem , is hopeless. if present. replace them . if 20 years old, what hope is any boot, really.
NO LIE,MISFIRE HAS 50 CAUSES.

not all are snap finger, easy to find, takes work and tools.



.

[fetcher]

OK. so misfire can have like 50 causes, but if the symptom was reported as first noticed just after power washing the engine, what is
reasonable to consider first?