2009 Corolla Walbro fuel pump no start problem??

**Axel** · 21-07-2015, 05:50 PM

Hi all,
so I've fitted a Walbro 255lph intank fuel pump in my 2009 ZRE152R Corolla and I'm having a problem.
Intermittently the car wont start.
When it does start it idles fine and runs really well.
Here's the trouble shooting I've done so far.....
I read that these pumps are very sensitive to low voltage so I hooked up a separate power feed direct from battery and thru a relay switched by the original pump power wire but this did not fix the problem.
I can confirm that when the car wont start the pump is getting power.
I have also found that when the car wont start, if I release some pressure from the fuel line the car then starts.
I am therefore assuming there is a fuel pressure sensor that is shutting off spark, I also believe this because while there is pressure in the fuel line the car should still start even if the pump doesn't run until the fuel runs down.
If I am correct can I disconnect the fuel pressure sensor or by pass it or is this not recommended.
Or, should I fit a pressure regulator?
Or am I on the wrong track and is it something else?
Any suggestions would be appreciated.

**Axel** · 21-07-2015, 08:25 PM

OK I think I figured out the problem.
Because the Walbro pump wouldn't fit into the factory filter/pump carrier I ditched the filtering part and ran the fuel line directly from the pump outlet then installed an external fuel filter.
Well....installed in the pump carrier that I scrapped is the factory fuel pressure regulator. DOH!
So I will have to fabricate a new housing for the regulator module to fit into that can then sit between the pump and outlet from the tank.
That should then prevent a pressure buildup beyond factory requirement but still allow sufficient fuel flow capability to meet the needs of other modifications.
Fingers crossed that solves the problem.....looks like a day on the lathe and milling machine tomorrow..yay.