95 rodeo. not the Diesel right>? gasoline engine, the diesel has a timed pump....
GAS:
what engine? car has 2 or more as options... and fuel systems vary by ,(drum roll) engines.
my guess is this is your first EFI fueling system?
to test fuel rail pressure and its zero,
this must be done cranking, i bet you didnt know that 1/2 the cars
made, it must be cranked to get the pump to run..... right?
my second guess, is you dont own a $10 volt meter.
?
the engine has a ECU, this ECU sends 12vdc to the fuel pump using a Fuel pump relay.
does the relay close, cranking?
1/2 do just key on for 2 seconds.
while cranking. and running. so we use a voltmeter to see if that happens, not replace every part on car gue$$ing, wow are you rich?
The ECU/:PCM brain can cut fuel for 2 or more reasons
More facts:
the ecu cuts fuel cranking if the throttle is stuck wide open. (TPS sensor errors, do that....) (this is a FEATURE)
this is a "unflood feature in all EFI cars made" (modern say 1988 to now)"a feature stated in the operators guide, btw)
and if the ECU has an immobilizer OPTION, same thing, cuts fuel. (some cars cut fuel then spark)
the ECU also cuts fuel if the ECU even suspects spark is missing. (feature 3)
Does engine run on test fueL.
we do that first. the 3 second test fuel tests.
if that sounds good, we attach fueling next.
if it sounds bad, or engine is dead, we fix that next (timing belt slip?)
This feature prevents the crash and burn deal.. as seen on T.V... (ecu computer logic )
(and is by laws here... (called the Spark monitor inside the ECU...)
got 12vdc to the pump cranking, ?
at the pump 2 wires. not 6v, no 8v but at least 11vdc there... (it will be whatever battery volts are... cranking, (measure that too)
on cars that need to be cranked, to get pressure
you will ru not be able to hear the pumpn, with the Starter motor banging away.... so we use the volt meter and the fuel pressure gauge
to not get fooled... Dribble tests are ok, if no dribble cranking, but is in no way proof of good pressure.. if pump runs....
The injector dont work at 0 to 20PSI, sorry...
on some cars you get a prime pump action for 3 seconds, keyon.
but not all cars do that. so we just assume they dont and WIN. (Isuzu diffr, rules on diffr. engines.... sure are...)
got a meter? even a $10 walfart meter works..
end general rules and vast experiences...
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now the FSM pages, of facts: (factory serv. man)
the 2.2L runs for "2 seconds key on",
this is the prime signal.
its best to repeat it 3 times to build pressure from a breached system. (gauge breached it)
quotes from FSM: 3.2L
Turn the ignition ON and listen for the pump to run (it should run for 2 seconds). If necessary, cycle the ignition OFF for 10 seconds and then ON again, in order to build maximum system pressure.
2.2L
Note the fuel pressure with the pump RUNNING; it should be 41–47 psi (284–325 kPa). When the pump stops, pressure may vary slightly, then should hold steady.
"
now the other engine. 3.2L
it say it needs to be cranked or run to check
fuel pressure. in my book.
the fuel rail at the loop end has the fuel pressure test port. there. see it?
seen here,
41-46psi is running pressure,(or cranking)
and 35psi for the smaller gas engine.
the pressures matter, its not carb car its EFI.
do not be tempted by the dark side and hot wire
the fuel pump relay, if you do , most guys
burn to H3ll the ECU relay driver, ive repair so many ,its a crime.
they hot wire this relay socket slip for a second and boom, you just blew up a $400 ECU
pay me to fix that..... (nah , im retired, )
never hot wire, the EFI system.
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