86 Mazda 626 starting problem, need help from experienced mechanic?

Question

I already posted this question and someone gave me a link to auto zone that was of some help, but the car still won't start. If I spray starter fluid in the intake it starts long enough for the fluid to burn off and then dies. I replaced the fule filter and pump but it still won't work. When I turn the key part of the way I can hear the new fuel pump start working but when I turn it to the "start" position it seems like the pump stops. Is there some relay or something that might cause this? Does a faulty engine control unit cause a problem like this? Are there any experienced Mazda mechanics out there who can tell me what to do next? I don't have the money to pay a shop to fix it for me so I either have to fix it myself or give up on it. Thanks!

The car in a fuel injection non-turbo model.

I can't find a plastic cap on the fuel injectors that has anything to release air. There's on on one end of the manifold but when I take it off and look in the metal hole there doesn't seem to be anything their and poking a tiny screwdriver into it has no effect.

I found a vacuum hose that had come loose and I reconnected it but after spraying almost a whole can of starter fluid in over many tries and having the engine start for up to 8 seconds and reving with the gas peddle over 4,000 rpm it still dies when the fluid is gone.

Answer 1

Have you checked the fuel pressure at the fuel rail? Should be AT LEAST 35 PSI on up to as much as 60. How about that flexible line that connects the output of the pump to the metal line? If it has a rupture it will not develop enough pressure, as the fuel will just spray into the tank. That one got me before. If the pressure is OK, then you might want to look at the injector(s). Make sure they are being pulsed by the ECM. There is also a tach lead that may tie in at the ignition coil, it sends tach pulses to the ECM. The ECM will not pulse the injector(s) without a tach pulse.
EDIT:
I haven't looked this car up to see, but if it has a TBI instead of port injection, you could have clogged injectors. I suppose that's possible with the port type too, but less likely unless a batch of bad gas is involved. Also look at one of the injector electrical plugs with a voltmeter as someone cranks the engine. Voltage should be detectable while the engine is being cranked. No voltage means the ECU isn't pulsing the injectors. That may be the ECU or the lack of a tach pulse as I mentioned earlier. (even if all other sensors were bad, the system should at least attempt to limp). Myself, I'm still leaning on that small line in the tank leaking the pressure off.

Answer 2

After you crank the engine, there should be pressure in the fuel lines. If you disconnect the line between fuel filter and engine, fuel should spray if under pressure. If it does, the pump is not the problem. Are plugs getting wet when you try to start car? Pull off air cleaner and hold air flow door open with ignition switch on. You should hear both the fuel pump going and the injectors going. If the plugs don't get wet doing this, you might have plugged injectors, or plugged fuel filter. Another possibility is bad fuel (water in fuel), but this usually makes car run really badly after starting with starter fluid. Does not sound like pump problem to me.

Answer 3

OK here we go,,i have owned 5 of these car,s,,so i may be able to help you,,you said you could hear the fuel pump run when you turn the key on,,OK this is normal,,and it is also normal not to hear it when you try to start it,,there is a relay,,and it is located,,on the firewall when you raise the hood,,you,ll see a row of them,,there may be a cover on them,,if so it is going to be marked,,which one id the pump relay,,there is also a main fuse for the pump,,it is located under the hood in the secondary fuse box,,it will cause the car not to run,,because of lack of fuel,,also there is a bleed valve on the injector rail,,you may have to bleed out,,because of air in it,,it will stop the injector,s from getting gas,,and it will not start until you do bleed it,,if indeed it has air in it,,it,s easy to,,you just turn on the key,,go out to the injector rail,,unscrew the plastic cap,,take a small object,,and mash in a little on the valve,,it look,s like a tire valve,,this will bleed the air off it,,since you changed the pump ,,and ever thing,,you probably got a good dose of air in it,,after this it should start,,if not,,check your spark plug,s,,i was working on one once,,and found all 4 plug,s dead,,the owner said he had try ed to start it for 2 day,s after installing a pump,,and what he Had done,,was dry burn them,,i hope this help,s some.