Switching to Return Style Fuel Pump

[RADustin]

All,

Looking to swap to a return style fuel pump on a 2005 PI.

I can't get the fuel pump to prime before starting- but I do know if I short out the pump the engine will run.

I am sure I have a setting wrong- can someone knowledgeable please look over my attached tune.

Engine is in an old ford truck with all emissions pulled along with rear 02s. The inertia switch is also gone as is the FPDM. The stock fuel 'system' has literally been reduced to the single wire output from the ecm which drives a relay to the fuel pump, which has a mechanical regulator.

I imagine I am missing some DTC codes or similar and the fuel pump isn't priming. I don't see where to select no FPDM in the tune software which some post allude to. Not sure if it is an OS thing or what.

2005 PI 0001.hpt

Thanks!

[RADustin]

more info-

I probed around with a DMM and figured out I am getting +12V off the signal wire from the ECU. The problem is this voltage is dropping to around .2volts when the relay coil is in circuit. So for whatever reason, the wire is not sourcing enough current to flip the coil of the relay. I do not believe it to be a ground issue.

The trigger wire I am using is the green/yellow wire out the ecu that everyone says to use.

I played around with different tune configurations- none seem to make a difference. The trigger wire goes +12v at key on, and remains on the entire time the key is on. It does not 'prime' and wait for the engine to start to fire again.

I really don't want to hook the fuel pumps to the ignition, so I am hoping I can figure out what the problem is and get it sorted.

Please help!

[RADustin]

exactly how I have it wired...

http://westcoastmustangs.com/temp/re...nversion_1.jpg

[RADustin]

more searching- looks like I have some re-wiring to do.

although it does say the green/yellow wire can run a relay- where mine is not strong enough.

http://www.svtperformance.com/forums...ump-actuation&


I have thoughts if I can use a digital solid state relay and run it off the control wire that carries the correct signal. I'll talk to my electronics friend in the next few days.

It is confirmed the green wire is just hot with key on- and not modulated with the ecu tune.

[Kevin@JPCRacing]

more searching- looks like I have some re-wiring to do.

although it does say the green/yellow wire can run a relay- where mine is not strong enough.

http://www.svtperformance.com/forums...ump-actuation&


I have thoughts if I can use a digital solid state relay and run it off the control wire that carries the correct signal. I'll talk to my electronics friend in the next few days.

It is confirmed the green wire is just hot with key on- and not modulated with the ecu tune.

Get an FPDM from an 05up and wire it in like factory. I just bought a bunch of them at the U pull it junkyard for $12 each with the pigtail/connectors on them(a lot of different Ford's use the same fpdm). It is a solid state relay with a few extra functions added in. If you have high amperage fuel pumps, you could wire in a second one and just piggyback the control wire. Then set the PID's to 0, your voltage table to 14's at high fuel flow and lower values at idle cruise to keep it from returning a ton of heated fuel to the tank. I've used the FPDM to control a relay like you are trying to do but I've been wanting to try it the way I mentioned above for a while now. You could slow the pumps way down at idle and cruise, just enough to maintain base pressure and return little fuel to the tank. I recently wired a stock FPDM into my coupe and I'm running it from an AEM Infinity stand alone ECU and it seems to be happy. I didn't wire in the monitor wire but I could if I really wanted the data...

[Kevin@JPCRacing]

The other cool thing about running the PWM controls on outputs like fuel pumps is you can take a load off the electrical system. My single fuel pump is only pulling 5 amps at idle now instead of 17.

I installed a PWM controller on my cooling fan as well because I only had a high fan relay wired in previously. It was either full blast or off. It would draw upwards of 40 amps when running and sometimes blow a fuse when coming on. Now the car runs at 176 degrees with the fan on 20% and pulling less than 7-8 amps. Can't even hear it running and the soft start means no hesitations or instant load when it comes on. I noticed this is a Crown Vic you are working with, so you could do the same on the cooling fan if you still have the stocker from the Crown Vic. You could probably use a fan/controller from another Ford as well, I think most use the same frequency. My combo is a 98 Mark VIII fan with a controller from 08 Fusion. Only thing I don't know about is how much adjustment is available in the software for your application.

[kwcrandall]

Hey I know this is an old thread but I have a similar system from a 2005 police interceptor swapped into my 78 truck. I'm new to tuning and don't know what changes to make In the tune for everything to run correctly. What changes need to be made?