1993 MAZDA MX3
220,000 MILES
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GATERTAMER
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base 1.6L manual car starts for about 6 or 7 seconds then dies.
Dec 23, 2012 at 1:32 AM
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KHLOW2008
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Arer you able to restart?
Does feathering the throttle keeps engine running?
Dec 23, 2012 at 4:49 AM
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GATERTAMER
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it is able to restart and feathering the throttle does not keep it running...recent cooling system replacement including head gasket...... sounds to me like major vacuum leak.
Dec 23, 2012 at 6:56 PM
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KHLOW2008
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Did you check for trouble codes?
Once started are you able to rev it up before it stalls?
Was this problem present immediately after head gasket replacement or were you able to run for a while before it surfaced?
Dec 23, 2012 at 10:00 PM
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GATERTAMER
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trouble codes 3 and 5 show up...I can rev it up before it dies several times although it wants to hesitate unless I feather it...
I was able to run it for about 80 miles after the new gasket before this problem occured...It happened shortly after I was adjusting the distributor and the air fuel screw to better tune it.
Dec 24, 2012 at 3:06 AM
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KHLOW2008
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Code 03 is a fault with the distributor or its wiring. Check if any wires are broken or connection is loose.

Code 05 is not listed in our database. Reconfirm the code.
Dec 24, 2012 at 12:36 PM
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GATERTAMER
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rechecked.......... only code 03 shows.... however that has been present for several years now. I have read your fuel pump test procedure, but when I turn key on cant hear pump whirring,and no pressure is present until I start it then it reads about 18 or 20 lbs. Have 12.6 volts all the way to pump, have tried two used pumps both react the same way...thanx you have been a good help so far I think were almost there.
Dec 24, 2012 at 5:22 PM
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KHLOW2008
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Not all cars systems have the fuel pump priming at initial ignition on. he fuel pump would run onces you start cranking as it uses the starting signal to control the circuit opening relay which is part of the fuel pump circuit.

However there is a problem with the fuel pressure. At idling and vacuum applied to fuel pressure regulator, the reading should be 30-37 psi.

Without vacuum the pressure should be 38-46 psi. Check the pressure again and disconnect the fuel pressure regulator vacuum hose to test if the pressure increases.
If it is lower than expected, clamp the return hose and note if pressure increases.
Dec 25, 2012 at 1:51 AM
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GATERTAMER
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when turning over pump pressure jumps to about 40lb.....then drops to zero gradually over about 3 or 4 seconds as the car dies...cant keep running long enough to remove vacuum hose to regulator to test...would a fuel pump just go out or could it be going out slowly over several years?
Dec 26, 2012 at 10:21 PM
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KHLOW2008
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The fuel pressure should hold for more than 3 or 4 seconds. In fact there should be residual pressure at all times. Check the fuel pump, the check valve is bad or you could have a leak in the delivery line and if externally it cannot be seen, that would mean leaking in fuel tank.
Dec 27, 2012 at 1:58 PM
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GATERTAMER
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there is a unit with 3 fuel hoses attached to it next to the two-way check valve on driver side next to the fuel tank do you know what it is and what its purpose is?......on a protoge its called a check and cut valve. I removed the check valve and air blew into it from both ports... not quite sure how its supposed to work though.
Dec 27, 2012 at 10:58 PM
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KHLOW2008
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The check valve I meant is the one inside the fuel pump.

The external valve should be for the EVAP system. That has nothing to do with fuel pressure dropping.
Dec 28, 2012 at 2:24 PM
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GATERTAMER
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would that be in the entire pump unit or pump itself.....just put new fuel pump on and same results
Dec 28, 2012 at 8:46 PM
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KHLOW2008
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When you installed the new fuel pump, did you replace the hose linking the fuel pump to the housing? If your fuel pump is not equipped with a rubber hose, then the problem could be with the O'ring in between pump and housing.
Dec 29, 2012 at 12:09 PM
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GATERTAMER
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there is an o ring with the kit but a hose connects the pump to housing...what is o ring for?
Dec 29, 2012 at 11:05 PM
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KHLOW2008
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O'ring is for a different setup so is not applicable for your model. When installing tthe hose, was it clamped correctly?

You would have to test the fuelpump as well, new doesn't mean it is flawless.
Dec 30, 2012 at 8:13 AM
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GATERTAMER
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tried1 new pump and 2 used pumps...same problem with all of them..they all test good. pressure is 40 at start up then needle flutters to zero til it dies after a few seconds....could a line be plugged or a vacuum leak. got 12.6 volts to pump..hooked a test light to connector at pump..... when key is turned light pulses off and on like it should
Dec 30, 2012 at 8:53 PM
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KHLOW2008
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Test the fuel pump when it starts to flutter. Ensure voltage is available at all times and if the power supply cuts off when it was about to stall, it could mean a control problem rather than the fuel pump pressure.

Try cycling the ignition switch on and off a few times to get the pressure up and without starting engine, wait and see if pressure drops.
Dec 30, 2012 at 9:40 PM
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GATERTAMER
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voltage is present the entire time.....cycle engine and pressure drops about 10 lbs. after a minute or 2
Dec 31, 2012 at 3:15 AM
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KHLOW2008
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Does clamping the return hose makes any difference to the pressure drop?
Dec 31, 2012 at 12:27 PM
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clamping return hose and cycling engine fuel pressure builds to 65 lbs.but still starts dropping slowly..when unclamped pressure goes to 40lbs.then starts dropping....vacuum gauge reads steady when started could it still be bad head gasket or another vacuum leak?...brake booster again thank you for your patience
Dec 31, 2012 at 9:18 PM
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GATERTAMER
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i just unplugged the wire connector to the MAF and it will stay running with the gas pedal pushed down any ideas?
Jan 1, 2013 at 5:09 AM
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KHLOW2008
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Seems to be a fault with the MAF. Did you try cleaning the MAF? Any leaks between MAF and throttle body?
Jan 1, 2013 at 2:40 PM
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when checking the resistance of the maf should i test the connector or the maf itself?
Jan 1, 2013 at 8:08 PM
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KHLOW2008
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Yes, you should check the connector and its wiring for possible damage.
Jan 2, 2013 at 12:47 PM
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GATERTAMER
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all looks good...tested the resistance of the maf itself according to chiltons it failed 2 of the 3 tests...should i replace it? am i right in assuming we have eliminated any fuel problems since it will idle with the maf unplugged but as soon as i plug it in it dies?....one odd thing fuel pressure tester shows no pressure while it is idling with maf unplugged and i know it is good...wierd
Jan 2, 2013 at 10:59 PM
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KHLOW2008
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If the MAF test failed, then you should get a known good substitute to test.
Jan 3, 2013 at 12:00 AM
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GATERTAMER
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thank you for all your help......turned out to be the maf after all
Jan 5, 2013 at 11:37 PM
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KHLOW2008
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You're welcome.

Glad to know the problem has been resolved.
Jan 6, 2013 at 7:05 AM
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HINTERTECH
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I enjoyed this thankyou..MAF = "mass air flow meter" for those who got lost in the thread ,I was thinking what is the ministry of ag and fisheries got to do with a 30x..Thanks again lads..
Jan 8, 2013 at 11:08 AM