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-   -   Fuel pump rewire won't prime. (https://www.evolutionm.net/forums/evo-engine-turbo-drivetrain/763582-fuel-pump-rewire-wont-prime.html)

Ude Lose Jul 7, 2022 04:22 AM

Fuel pump rewire won't prime.
 
I have a complete fuel system in my evo 8, walbro 450 -8an feed with -6an return / 2150 fic injectors with agency power fuel rail and aeromotive fpr and I also have a stm rewire kit. The problem is that when i go to start the car the fuel system won't prime and I have to continuously crank the car to build fuel pressure to get the car to start. Shouldn't the fuel system prime when I turn the key?
I am running a 6262 and tuned by rrt.
Any help would or insight would be appreciated.

Biggiesacks Jul 7, 2022 05:32 AM

The ecu doesn't activate the pump until it gets a signal from the crank sensor on the engine. So if the lines were filed with air it would take a bit of cranking to purge that all out and get pressure. Should be fine after that. If not you might not be holding pressure on the feed side.

Ude Lose Jul 7, 2022 07:23 AM

That's strange because my friend has a butcher double pumper on his evo 9 and when he gets in the car and turns the key to accessorie the pump primes. He does not have the fuel pump rewire kit.

Biggiesacks Jul 7, 2022 07:34 AM


Originally Posted by Ude Lose (Post 11956255)
That's strange because my friend has a butcher double pumper on his evo 9 and when he gets in the car and turns the key to accessorie the pump primes. He does not have the fuel pump rewire kit.

:dunno: Dunno what to say about your buddies car, but that's how the stock ECU works. I'm not sure how you install a double pumper without a wiring job though.

huzzle101 Jul 7, 2022 07:59 AM

Mine also primes when i turn the key to on, I also have a bulletproof double pumper but i am also on a Haltech elite.

Biggiesacks Jul 7, 2022 08:20 AM

There is a tool in evoscan that will let you run the pump with just the ignition and the engine not running. Bottom right under actuators. You can use it to prime/test/purge the fuel system.

Ude Lose Jul 7, 2022 11:29 AM


Originally Posted by Biggiesacks (Post 11956258)
There is a tool in evoscan that will let you run the pump with just the ignition and the engine not running. Bottom right under actuators. You can use it to prime/test/purge the fuel system.

if that option is activated will the car prime when turning the key before cranking?
Permanent setting?

I checked all the fuses and relays and everything was good.

Biggiesacks Jul 7, 2022 11:55 AM


Originally Posted by Ude Lose (Post 11956268)
if that option is activated will the car prime when turning the key before cranking?
Permanent setting?

I checked all the fuses and relays and everything was good.

No, the way it works is you turn the key to on and click activate in evoscan. Then it runs the pump for a few seconds. You gotta repeat it a few times to purge all the air. There's a button for high and low speed fuel pump circuits.
This is really a MUT diagnostic option, and I'm sure there are OBD reader tools out there that could do the same thing.

You should only have to do this once. After the air is out it should crank and start like normal. If not, you have some other issues.


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