S54 Fuel Wiring

[Thing30]

Hi everyone, looking for some clarification on wiring the S54 fuel pump. I've read that the S54 EKP module must be used because it's a pulsating signal, correct? I've also read some people not using the EKP module. I don't have the X6021 connector in my case, however, I've already cranked over the motor and it idled just fine without the X6021 connector or EKP module. I intend to use a relay on the fuel pump wire and connect the X60002 fuel pump signal to it, That's it. Any detrimental effect this may have? Thanks

[Garageaholic]

Yup definitely needs the EKP Module. Pinouts are super easy too. You shouldn't need a relay if you're using the EKP.

And just because it idles doesn't mean it won't choke under load. Use the EKP.

From another thread on this forum on this topic:

EKP-modul [regulated fuel pump relay must be used, the E30 relay will not work properly,]
EKP pin 1 [pulsating signal from mss54 connector X60002 pin 11 then to X6021 pin 1 black/violet (black 4 pin connector), I just wired this directly]
EKP pin 2 [to fuel pump,to whatever pin is on your E30 for fuel pump]
EKP pin 6 [battery +12]
EKP pin 7 [ground]
EKP pin 8 [switched +12, DME relay X6021 pin 2, white/red wire]


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[Thing30]

Thank you for the clarification. Is there a way of using the EKP module without using the X6021 connector?

[Garageaholic]

Yeah IIRC I think that one or two wires were the only ones useful and I just added the remaining wire(s) to the X6011. The purpose of the x6011 is to allow you to easily separate it from the engine harness if you were to remove the engine.


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[Thing30]

I see on the diagram posted above there's a violet/Black and red/white wire that connects to X6021. I don't have this connector though
My plan was to wire the black/violet wire from X60004 which is fuel pump signal directly to EKP pin1
EKP pin 2 to fuel pump
EKP pin 6 battery 12v
EKP pin 7 ground
EKP pin 8 no clue without X6021

[FredK]

I hooked up EKP pin 8 to C101 Pin 7, a switched hot basically taken very close to the fuse box which is how it's arranged in a donor car.

I think there are variations between years as to where the BK/VI fuel pump activate wire is located, on my Z3M harness, it was at X60002 pin 11.

[Thing30]

Thank you for the information! Interesting, my X60002 connection has bk/vi out of pin 11 and it's an 03 e46 motor. Hopefully I could finally get this thing running soon.

[Garageaholic]

Have you gone to BMWs WDS and looked up the wiring to your specific s54 model?

That would answer a lot of questions on the wires, colors, gauges, and where it goes.
I picked up a DVD from eBay for like $12. Helps a ton for engine swaps!!


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[diesekte]

You don't definitely need the EKP module. I don't have one.

[Thing30]

Have you gone to BMWs WDS and looked up the wiring to your specific s54 model?

That would answer a lot of questions on the wires, colors, gauges, and where it goes.
I picked up a DVD from eBay for like $12. Helps a ton for engine swaps!!

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That's a good idea. I pulled up wiring schematics and have been working that way. Along with information on the forum.

You don't definitely need the EKP module. I don't have one.

So you didn't use one? How did you end up wiring the fuel pump and signal? How does it run?

[diesekte]

If I remember correctly the EKP module was a US thing only. Might be wrong on this.
Anyway, I never had one... The harness I got came without it and the tune I got seemed to work just fine. I was tuned by a shop in DFW and had unrelated issues and then ended up getting a tune by markert. I make good strong power all the way up to 8200. I never have experienced fuel starvation or lag (besides what is inherent in an electronic throttle system) or anything "off" by not having one. I remember inquiring here when I found I didn't have one and was told I didn't necessarily need it

[Thing30]

If I remember correctly the EKP module was a US thing only. Might be wrong on this.
Anyway, I never had one... The harness I got came without it and the tune I got seemed to work just fine. I was tuned by a shop in DFW and had unrelated issues and then ended up getting a tune by markert. I make good strong power all the way up to 8200. I never have experienced fuel starvation or lag (besides what is inherent in an electronic throttle system) or anything "off" by not having one. I remember inquiring here when I found I didn't have one and was told I didn't necessarily need it

Same here, only received the engine harness in my case. I was going to simply put a relay, That fuel pump wire was getting too hot. But it cranked over just fine and rev'd well without the EKP module. I Purchased the module already, so I'll be using it.

[nando]

You don't need the EKP - you can run it off the 'euro' fuel pump pins that use a standard relay like a stock E30. Interestingly enough, the standard relay pins are active on the US DMEs, but the EKP isn't enabled on the euro DMEs.

you can't hook up a standard relay to the EKP pins though, because it's a PWM signal. It's been ages but you can find the correct pins for a standard relay in the ETM/WDS somewhere.

[terraphantm]

You don't need the EKP - you can run it off the 'euro' fuel pump pins that use a standard relay like a stock E30. Interestingly enough, the standard relay pins are active on the US DMEs, but the EKP isn't enabled on the euro DMEs.

you can't hook up a standard relay to the EKP pins though, because it's a PWM signal. It's been ages but you can find the correct pins for a standard relay in the ETM/WDS somewhere.

The EKP output is actually active on Euro DMEs (I've run euro software on mine and am currently running CSL software). It's just set to 100% duty cycle all the time.

[Thing30]

So I wired it directly to the EKP module and it's running! I did notice that it demands from the fuel pump intermittently, is that where it's "pulsating"? I'm running a 255 Walbro with the inline factory filter and regulator.