Adzn3k Posted August 30, 2019 Report Share Posted August 30, 2019 Hi guys I recently fitted a fuel pressure sensor and I'm seeing a differential pressure drop when on boost. As soon as the car sees positive boost the differential pressure starts to drop progressively and at 0.8 bar its showing a drop of 1.5bar. I'm still on the stock fuel pump wiring which has a resistor pack, the cars running a walbro 225, a dwr1000 fpr and id1000 injectors. I have a feeling the stock wiring setup is what's causing me the issue. I'm looking at changing the walbro 225 out for a 450 and then making my own wiring and control the new pump via pwm and an ssr I've searched and found this wiring diagram: After reading the threads it seems that the jury was still out of the above diagram is the way to go. Quote Link to comment Share on other sites More sharing options...
Richard Hill Posted August 30, 2019 Report Share Posted August 30, 2019 A reliable method I use is to cut the positive feed near the fuel pump and insert a standard relay. Use the original supply wire to Terminal 86 to positive trigger the relay, hard ground terminal 85 and then Run a 2.5mm fused wire directly from the battery to terminal 30. Terminal 87 supplies power via the original short wire to the pump. HTH, Richard. Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted August 30, 2019 Author Report Share Posted August 30, 2019 Yeah I could do that but I don't want to. I want to control the fuel pump speed via pwm Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted August 30, 2019 Author Report Share Posted August 30, 2019 I was thinking of using this ssr: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F172960873291 Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted September 19, 2019 Author Report Share Posted September 19, 2019 Bump on this, Quote Link to comment Share on other sites More sharing options...
cj Posted September 20, 2019 Report Share Posted September 20, 2019 or you could wire in an external pump controller which is PWM capable. There is a ford unit that is used in a lot of 2000's era jagaurs, fords, etc and is very similar to the controller sold by nzefi. Similar era subaru's with ez30's and I think a bunch of the later turbo models also had similar controllers. Most of these should be available in a junkyard for cheap. They typically take 12v, ground, and PWM inputs, then the PWM control the fuel pump on the 2x output wires. Quote Link to comment Share on other sites More sharing options...
Leonv33 Posted September 20, 2019 Report Share Posted September 20, 2019 On 8/30/2019 at 6:10 PM, Adzn3k said: Hi guys I recently fitted a fuel pressure sensor and I'm seeing a differential pressure drop when on boost. As soon as the car sees positive boost the differential pressure starts to drop progressively and at 0.8 bar its showing a drop of 1.5bar. I'm still on the stock fuel pump wiring which has a resistor pack, the cars running a walbro 225, a dwr1000 fpr and id1000 injectors. I have a feeling the stock wiring setup is what's causing me the issue. I'm looking at changing the walbro 225 out for a 450 and then making my own wiring and control the new pump via pwm and an ssr I've searched and found this wiring diagram: After reading the threads it seems that the jury was still out of the above diagram is the way to go. This:https://www.nzefi.com/product/fuel-pump-pwm-speed-controller/ Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 20, 2019 Report Share Posted September 20, 2019 On 8/31/2019 at 1:53 AM, Adzn3k said: Yeah I could do that but I don't want to. I want to control the fuel pump speed via pwm What are you trying to achieve by PWM? Is it a noisy pump? Remember when you are idling and cruising fuel pressure is naturally lower so pump current is lower all on its own without any intervention. Gsab 1 Quote Link to comment Share on other sites More sharing options...
Adzn3k Posted September 20, 2019 Author Report Share Posted September 20, 2019 It's mainly to bin the stock setup Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 21, 2019 Report Share Posted September 21, 2019 9 hours ago, Adzn3k said: It's mainly to bin the stock setup In that case the recommended option would be to do it as per Richard Hills advice - keep it simple and only add complexity where it is needed. PWM is just going to add complexity and more tuning with no real benefit. DenisAlmos and Gsab 1 1 Quote Link to comment Share on other sites More sharing options...
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