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-   -   Spark but no fuel 90 Miata w/95 motor (https://www.miataforumz.com/na-1989-1997-8/spark-but-no-fuel-90-miata-w-95-motor-1466/)

3 bar May 24, 2013 07:16 PM

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.

sixshooter May 27, 2013 10:42 PM

Did you take any wires loose? Grounds? Fuses? Try swapping relays?

3 bar May 28, 2013 12:32 PM

Could I have the timing 180 out at the crank?

3 bar May 28, 2013 12:35 PM

Was able to get the fuel pump to come on jumping the diagnostic port but it still wouldn't start.

Mymiata95 May 29, 2013 08:52 AM

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.

sixshooter May 29, 2013 06:23 PM

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.

3 bar Jun 24, 2013 10:55 PM

So replace the CAS? Replaced the coilpack and the ecu

sixshooter Jun 26, 2013 07:21 AM

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?

sixshooter Jun 26, 2013 07:24 AM

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?

3 bar Jun 26, 2013 08:27 AM

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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