Spark but no fuel 90 Miata w/95 motor - Miata Forumz - Mazda Miata Chat Forums
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NA (1989-1997) NA Miata discussion within. The MX5's first generation, the NA, sold over 400,000 units from 1989 to 1997.

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Old 05-24-2013, 07:16 PM   #1  
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Default Spark but no fuel 90 Miata w/95 motor

Two months ago I swapped a 95 motor using the flyin Miata kit in my friends 90 Miata cause he had the short nose crank issue. Got the car running but he was complaining about lousy gas mileage (only 175 miles per tank). Checked the timing belt and set it up according to "Miata Mikes" YouTube video. Put things back together and attempted to start it but now am getting no fuel pressure. Jumped #2 and #5 on the diagnostic port and heard the fuel pump. What could be the problem? Got spark but no fuel.
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Old 05-27-2013, 10:42 PM   #2  
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Did you take any wires loose? Grounds? Fuses? Try swapping relays?
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Old 05-28-2013, 12:32 PM   #3  
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Could I have the timing 180 out at the crank?
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Old 05-28-2013, 12:35 PM   #4  
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Was able to get the fuel pump to come on jumping the diagnostic port but it still wouldn't start.
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Old 05-29-2013, 08:52 AM   #5  
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I recently had the same issue with my 95. After two weeks with my mechanic, he narrowed it down to the 6" long wiring harness going into the fuel pump. It had worked itself lose and was corroded. You apparently can't buy just this wiring, Mazda wants to sell the fuel pump and the sending unit (I think that's what my mechanic called it) which will include the wire. Mine is running again, but without replacing the wiring, my mechanic says it will happen again.

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Old 05-29-2013, 06:23 PM   #6  
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The fuel pump won't run if there is no CAS signal as a precaution in case of a severe car accident. You get an initial pulse to the pump on key on and then it waits for a signal from the engine sensors before resuming operation.
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Old 06-24-2013, 10:55 PM   #7  
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So replace the CAS? Replaced the coilpack and the ecu
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Old 06-26-2013, 07:21 AM   #8  
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I'm a bit confounded by the fact you are getting spark. I'm reasonably sure no CAS signal = no spark.

1. If you keep the fuel pump jumpered so it will run all the time, does it crank?

2. Are the spark plugs wet with fuel when you pull them out and check them?
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Old 06-26-2013, 07:24 AM   #9  
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On my '96, the fuel pump won't run unless the crank sensor gives a signal. Is the crank trigger hooked up and oriented correctly with regard to the toothed wheel?
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Old 06-26-2013, 08:27 AM   #10  
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Won't start with pump jumpered. last time I checked when pulling out a plug I was getting a spark. The only thing I haven't changed was the cas
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