Fuel Pump Relay?

[Vandal1987]

Just wondering does a hotwire kit from Racetronix eliminate the need for the original fuel pump relay that was in the engine compartment. thanks in advance.

 

[pacecarta]

you could rewire the original relay connector to not need it but if you just connect the hotwire you need a good working stock relay to activate the hotwire relay

 

[Vandal1987]

you could rewire the original relay connector to not need it but if you just connect the hotwire you need a good working stock relay to activate the hotwire relay

Thanks Pacecarta I appreciate the advice. I am just trying to clean up my stock harness getting rid of what I don't need (running XFI)

 

[GNRick]

My car starts fine with hotwire. Fuel pump relay is melted. I even disconnected it and car still starts right up. Also factory oil pressure sender is MIA. Could the previous owner have connected the oil pressure sender wires to the wires coming out of the fuel pump relay?

 

[Vandal1987]

I got off the phone last night with somebody frM Racetronix he told me the fuel relay and oil press sender need to be in working order if u run the racetronix setup.
But thanks Rick that's a really useful nugget of info I will def keep that info in mind.

I am not too sure if resoldered connections in the harness will yield the same consistent connection strength as if I were to get a custom harness made up. But the unit I am looking @ (Caspers) is 800 bucks. What do u guys think spend the money or risk it with the stock chit

 

[TurboBuRick]

If the stock harness is in good condition (not all hacked up with exposed wire) I would role with it.

1 of the 2 things need to happen in order to pull in the hot wire relay. Either the stock relay or the oil switch needs to close.

The stock relay and oil switch can be eliminated. In that case the signal wire on the stock relay plug could be jumped to the old pump feed which becomes the hot wire signal.

Ricks car must have a jumper somewhere or power is being fed through the fuel pump test wire behind alternator.

 

[Vandal1987]

Ok my stock harness is not too too bad I will get a diagram of the wires I have deleted out of the equation and post up when I get home.

So if I hard wire right into the Into the fuel pump power source that runs to the rear of the car this will suffice(green white wire from relay hard wired into grey wire)?

Fwiw I running a double pumper with racetronix harness. I asked about that when I got a phone call from Racetronix but was unclear on the answer I got, (too much noise pollution while on phone) I remember him saying it might run both pumps constantly which doesn't make sense to me because the 2nd pump is triggered via Hobbs switch right? Any how I am going to post up what I deleted from my harness and maybe u guys could point in the right direction on what I did wrong and need to redo or what else I won't need anymore. This discussion has been a real learning experience for me to say the least

 

[Vandal1987]

This is what has been deleted from the wiring harness Thus Far. I have included some homemade visual aids (no printer or M/S paint )... The Highlighted Portions Represent what has been deleted from the ECM Pin connectors as well as the C100 bulkhead...

I have also included a diagram on how I interpreted the bypassing of the Fuel Relay and Oil Press switch that was explained to me from the previous posts..... Please leave any input as to what I have done wrong up to this point or any other connections/relays that can be deleted from the harness.

I will be running a very rudimentary harness basically just what I need to run the motor properly.

 

[pacecarta]

i like to eliminate any connections from the old harness that could cause an issue
run a new wire from the prime..either at ecm connector A1 (12v fuel pump) to the RTX main hotwire relay coil feedor XFI B5 ( grounding for main pump relay coil) theres a loop connector that can be cut to make this possible
you can also follow that by running from the XFI aux 2 out pin B2 (grounding for a relay coil ) to the secondary pump relay ground (find at the loop connector ) and eliminate the hobbs for the second pump . with aux 2 you can program the turn on based on tps and map

 

[pacecarta]

you also could have left the egr wires (diagnostic /control /12v and ground)as the caspers adapter has a jumper inside to convert the diagnostic and control wires to aux 1 and aux 2 input for easily adding a fuel and oil pressure sensor
they sell a kit with the harness for the egr plug and sensors to make it easy

 

[Vandal1987]

Wow PacecarTA I really like the sound of eliminating the Hobbs switch!! I wanted to do something that would run off the ECM signals but just didn't know how to go about it. That method seems a heck of a lot more reliable not to mention less wiring and parts to look @ under the hood. I will have to pin that up when I get my XFI box.! Would u runner a thicker gauge or just run the same diameter wire to the fuel pump directly?

 

[pacecarta]

its only controlling a relay coil , draw is under 1/3 amp , ive even used the rear speaker wires to operate the relays because those wires (four color coded wires) are already at the kick area and they run under passenger side sill plate to the trunk

 

[Vandal1987]

That would really simplify the install. I will draw up another diagram tonight to see if I have intereprted what u said correctly.

 

[Vandal1987]

k so do I got this right???? and then the 2nd pump activated @ pre determined voltage and boost readout via the TPS and MAP sensors ( have to set that up when car is getting tuned)

 

[pacecarta]

no ,
for the main pump run a1( to the factory pump power feed that goes to the rtx relay , specifically the positive side of the relays coil ... the tan wire in the trunk on driverside in the taillight harness that the original fuel pump ran on
for the secondary theres a loop connector on the rtx harness that you remove to install the hobbs wiring
cut the loop and youll find one side is connected to ground , the other side is the coil ground for the rtx relay (unplug relay and youll see the wire tests open). run the aux2 output wire from xfi (B2) to the rtx relay ground wire
in the xfi you can test the secondary pump relay operation by temporarily changing the aux 2 outputs settings tps 50% and min threshold kpa to to something below atmosphere (90 works) , now key on engine off when you press the gas pedal over 50% it will activate aux 2 output and the pump should run ...reset the min threshold setting to something like 12psi (180kpa)

 

[Vandal1987]

Awesome !!!..k , I think I got it this time thanks for explaining it in more detail. I am going to do the same drill post up a diagram to make sure I have got it.! Thanks again PacecarTA!!

 

[Vandal1987]

Hope I got this time.....

 

[pacecarta]

your pics suck
cut the tan at trunk driver corner and run from the end that goes toward pump to A1 at ecu connector after the casper box (or use B5 at xfi to ground the main rtx relay)
cut the loop at the rtx connector that controls the second pump and run the end that the relay uses for ground (not the end that is ground) to the aux2 out pin B2 at the xfi
use whatever wire you want (i'd run 18awg) , unless you rewire the rtx harness the connector with the loop will be under the hood

 

[Vandal1987]

lol Yea there pretty cheesy eh.. Anyhow I got it now thanks man. I will be sure to add what I did with REAL pictures. It wont be for a while but I will get to it as soon as I get it rigged up!!