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-   -   New fuel pump, priming sound, no start (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/new-fuel-pump-priming-sound-no-start-1129565/)

carcrank 08-31-18 05:39 PM

New fuel pump, priming sound, no start
 
On an 89 convertible, I replaced a fuel pump because I have tried most things to get the newly rebuilt motor to 7k rpm, but it wont get there. It faulters at 6000 rpm. So I installed a new fuel pump. With the ignition on, it makes a light whirring sound, as if it is priming the system. It only goes off when the key is turned off, and the motor wont start now (definitely not getting fuel). Any ideas on what else I could try?

The rubber hoses looked dirty , but in okay shape, and I would think it wouldnt make any sound if the wiring were wrong.

TIA!

_NGL 08-31-18 07:12 PM

The fuel pump doesn’t/shouldn’t prime when you turn the ignition. The ECU only turns on the pump when you crank/start the engine.

DR_Knight 09-08-18 07:00 PM


Originally Posted by _NGL (Post 12297954)
The fuel pump doesn’t/shouldn’t prime when you turn the ignition. The ECU only turns on the pump when you crank/start the engine.

might want to double check this statement. Pretty sure the pump will prime then shut off when ignition on. Upon cranking, maf sends signal for pump to continue to run. My s5 does this.. and I can hear it with a walbro in the tank

DC5Daniel 09-08-18 07:11 PM


Originally Posted by DR_Knight
might want to double check this statement. Pretty sure the pump will prime then shut off when ignition on. Upon cranking, maf sends signal for pump to continue to run. My s5 does this.. and I can hear it with a walbro in the tank

Ditto. My standalone does the same to mimic the stock behavior.

_NGL 09-08-18 10:39 PM

Ah, my fault. Seems to be an S5 operation.

My S4 doesn’t do this, excuse and disregard my previous statement.

sorry!

NCross 09-17-18 05:47 PM

Is it wired backwards?

Templeton 09-18-18 01:59 PM

Make sure you have the lines at the pump in the correct orientation. It's not too hard to to swap the send with the return line.

mazdaverx713b 09-19-18 05:30 AM

My question is why are you taking a freshly rebuilt engine to 7000 rpm? There's a break in period for at least 500 miles of varied driving. I would not take a fresh engine to redline.

With that said, have you checked for any vacuum leaks and have you verified that the timing is set properly? Were the injectors cleaned and flow tested before install? Have you checked all grounds to ensure they were clean and tight?

rangertimmy 11-13-18 06:22 PM

Mine does when I turn it to acc. I dont have to crank the engine to hear the pumps prime. In fact, I wait to hear them before cranking.


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