Put in new computer now car wont stay running runs for 30 seconds then fuel pump shuts off
SOURCE: I need to find the ECU relay for an 86 NISSAN 300zx.
The ECU is probably under the passenger seat. The battery also has a fusible link which may be blown. Also follow the battery wiring to the regulator box. This may also be faulty.
SOURCE: car wont start
Fuel delivery must be confirmed with a fuel pressure gauge on this vehicle. Disconnecting the fuel line and cranking the engine to see fuel shooting out does not confirm pressure, it only confirms fuel delivery. Remember you need both fuel delivery and pressure. On this vehicle if the psi is off by just one number that's enough to keep it from starting. Also replacing the coil and rotor (as you stated) does not confirm that spark is reaching the plugs. Confirm that both spark and adequate fuel pressure are reaching ALL the spark plugs.
SOURCE: my 1985 nissan 300zx stays
Hi, there are many reasons why your car would run for some seconds, less than 45 seconds, 45 seconds or more than 45 seconds and shut down, so i would let you know all the reasons and possible cause of the problem.....
An engine vacuum leak. Check for loose or broken vacuum hoses, leaks around the intake manifold gasket or throttle body, leaks around the PCV valve and EGR valve.
A dirty or defective airflow sensor. A sensor that has been
contaminated by fuel varnish or dirt will under report airflow and be
slow to react to changes in airflow. This can upset the air/fuel
mixture causing idle, stalling and hesitation problems. Cleaning the
airflow sensor wire with aerosol electronics cleaner can often restore
normal operation and cure the problem.
A defective idle speed control system. Idle speed
on a fuel injected engine is controlled by allowing a small amount of
air to bypass the throttle. If the idle air bypass circuit is plugged
with dirt or fuel varnish, or the solenoid valve
is sticking or broken, the engine may not get enough air to idle
normally causing it to stall. Cleaning the idle air bypass circuit in
the throttle body with aerosol throttle cleaner will often remove the
gunk and solve your stalling problem. If a good soaking with cleaner
fails to fix the stalling problem, check the wiring connector. It might
be loose or corroded. If no wiring faults are found, you may have to
replace the idle speed control solenoid.
A faulty coolant sensor. If the coolant sensor is bad and tells the PCM
the engine is colder or warmer than it really is, that can screw up the
fuel mixture, too. If the coolant sensor reads colder than normal, or
cold all the time, the engine will run rich. This won't cause cold
stalling but it can make for a rough idle once the engine warms up, and
it kills fuel economy.
If the coolant sensor reads warmer than normal, or reads hot all the
time, the PCM will lean out the fuel mixture too much, causing the
engine to stall when it is cold. See the article on coolant sensors for
how to test the sensor. Replacing a defective coolant sensor will cure
this cause of stalling.
A faulty air temperature sensor. This sensor tells the PCM the
temperature of the air entering the intake manifold. The PCM needs an
accurate input so it can balance the air/fuel mixture properly. Just
like a bad coolant sensor, a bad air temperature sensor can upset the
fuel mixture causing stalling problems.
A bad Manifold Absolute Pressure (MAP) sensor. This sensor monitors
intake vacuum, which the PCM uses to determine engine load. If the MAP sensor
is not reading accurately, the PCM may add too much fuel or not enough,
causing the engine to stall. See the article on MAP sensors for how to
diagnose this sensor.
Low engine compression. If your engine has a lot of miles on it and compression is low because the piston rings
and/or cylinders are worn, ot it has one or more leaky valves, it may
not have enough oomph to keep idling. A compression check will tell you
if this is a problem or not, and if it is there's no easy fix other
than to overhaul or replace the engine.
Worn or fouled spark plugs.
Ignition misfire can make any engine stall at idle. When the engine is
running slowly, there is less momentum to keep it going, so a bad
misfire may cause it to stall. If the spark plugs have not been changed
in a long time, a new set of plugs and/or plug wires can restore a good
hot spark and eliminate the misfire. A weak ignition coil or a faulty crankshaft position sensor may also cause a stalling problem.
Bad gas. Gasoline that contains too much alcohol (more than 10%), or
gasoline that has been contaminated with water or some other substance
may not burn well and cause your engine to stall. If the stalling
started to occur shortly after your last fill-up, suspect bad gas. The
cure is to drain the tank and refill it with fresh gas from another
filling station, or just use up the bad fuel (if the engine runs okay
at highway speeds), then refill at another station when the tank is
near empty.
173 views
Usually answered in minutes!
×