86 300zx starts,Runs if primed and once primed fuel has run out turn off,seem yo me that my injectors are not working. I traced the wiring from injectors to comp. also relaced f/p,computer,injectors,relays according to the manuel i am getting the voltage to the components but it still seems as the injrctors don't pulsate what to do ?????????
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although rare it is possible to destroy the fuel pump by running tank to m/t , a quick check to see if this is the case is to sit in car with door open , hold your foot on door jam switch (stops chime) and turn key to run (not start) once or twice in a row , if your pump is still working , you will hear fuel injectors prime , (elect motor runs for three seconds ) you may have to listen carefully and repeat test several times to hear it (quiet place helps !!) if you don't hear the pump prime !! and you ck/replaced the fuel pump fuse already , it will need replaced (its inside fuel tank !!)
You aren't describing when this occurs. If you are simply turning the key to the ON position, but not cranking or starting the engine, this is normal. The pump goes through a 3-5 second "Prime" to bring fuel pressure up for the injectors. Once the engine starts, the ECM uses another electrical path to run the fuel pump during operation.
if it has spark and only tries to sart when you prime then it is a fuel problem. pull the fuel hose where it connects to the injectors and run it into a container then turn on the key and see of fuel runs into the container, if not you need a fuel pump or filter. careful not to spill fuel all over the place. have someone turn on the key while you watch if fuel comes out so they can turn key off right away and not burn your stuff down.
And you know the fuel filter is good? Could be injector problem: just as a check, spray some starting fluid into the intake and see if engine runs a few seconds. If it does, it is a fuel problem. Check injector fuse, as a start. Check fuel pressure. Check injector circuit. If engine won't start with starting fluid, check if you are getting spark. Problem may be in the ignition system.
filling the filters before installing will make priming go more quickly. once the pump is primed crack open the fuse line at the injector while cranking until you have fuel pulsing out, close it then move on to the next injector. keep doing this until the engine runs smoothly. it may start running before all the injectors have been purged so keep clear of all moving parts and a fire extinguisher handy would be a good idea.
Most vehicles have a "system prime" that occurs when the ignition key is moved to the "ON" position. This is where the key ends up after you start the engine. This prime runs the fuel pump a second or two to get the fuel pressure high enough for the injectors to work once you crank the engine. The prime is performed by the fuel pump relay. In a quiet area (minimal noise, no radio), sit in the vehicle and turn the key to the on position without cranking the engine. You sgould hear a 3-5 second buzz or hum. This is the fuel pump coming up to pressure. If this is not occurring, then either the relay or the pump is most likely bad.
It sounds like the fuel pump is not working. Perhaps the install was not completed correctly. Things to check, fuel pump relay, wiring, voltage to the pump.
The priming happens as soon as you put the key in and turn it to "acc" (you may hear a humming sound). Then once you turn it to "start" the injectors and spark plugs start firing.
Another possibility is that the fuel filter was installed backwards.
i have the same problem on a 98 jimmy 4.3 4x4.
i replaced the fule pump and have good pressure.
new wiers & coil (good spark) no MIL & no codes.
will only start when primed. it will run & drive all day
with no problems.
but once it has been turned off (warm or cold) i will
have to prime it once again to start it.
i have another engine that was in it before it spun a bearing.
it ran fine so i know all parts are good.
i swaped the mass air flow and throttle body but i still have
to prime it everytime to start it. am i forgetting something?
should i swap out the intake with the injectors?
any help would be sweet. thanks.