Walbro 525 wiring

[sleet142]

Well as I understand it, the EPK is now just a dumb switch. It will never see LPFP pump load since it no longer provides power to LPFP, it just simply sends signal to a relay. So if the above statement from @jts1981's mechanic is correct, it would seem irrelevant what relay there is as the EPK would never see the LPFP power in either mechanical or solid state case. And again, this is for primary LPFP signal from EPK.

Essentially it does become a dumb switch. It will no longer see the load of the current from the pump. Which is why you can leave the fuse for the EKP stock. The EKP changes the duty cycle based on the lpfp sensor reading. For example, if the sensor broke it would run the pump at full tilt due to not knowing the output of the lpfp.

The voltage from the EKP is 12v. So when you start to turn on and off that 12v(through pwm/duty cycle), you can have a lower voltage applied at the pump, which is how it drives it slower.

With the relay now between the EKP and the fuel pump, the relay needs to be able to keep up with the duty cycle that the EKP operates at. A mechanical relay cannot switch on and off fast enough to be able to modulate the 12v from the battery to the pump so it will run the pump at full voltage from being stuck in the on position. But in the case of the solid state, it can turn on and off fast enough to keep up with the duty cycle from the EKP. So the solid state now will cycle the 12v from the battery at the same duty cycle that the EKP is telling it to do. Thus lowering the effective voltage at the pump.

 

[sleet142]

please refer to my pics of the scanner for what I mean about the car not reading the fuel pump, and the other pics showing phase c, phase b....

I personally dont have a scanner to see if it is connected or not. Could I check through INPA to give you an answer?

 

[jts1981]

The EKP changes the duty cycle based on the lpfp sensor reading.

There it is...e89 for what ever reason does not have lpfp sensor

 

[sleet142]

Hmm. From what I found it does mention not having a lpfp sensor. But it doesn't describe where the feedback is coming from on how the EKPS knows what voltage to apply to the fuel pump.
"Discontinuation of the fuel low-pressure sensor

On the E89, the fuel low-pressure sensor has been discontinued.
The high-pressure pump raises the fuel pressure from 50 to 200 bar. The high-pressure line delivers the fuel to the rail. In the rail, the fuel is stored temporarily, then distributed to the injectors. The rail-pressure sensor measures the current fuel pressure in the rail. When the quantity control valve in the high pressure pump opens, the excess fuel delivered is returned to the inlet. If the high pressure pump fails, restricted driving is possible."

https://www.newtis.info/tisv2/a/en/...lity-control-valve-msv/voltage-supply/XBpOQ2l

 

[Erichale77]

Wouldn't the PM4 LPFP controller alleviate these EKP issues? It allows DME to control both pumps (or one pump) on a 40 amp circuit each.

 

[fmorelli]

Hmm. From what I found it does mention not having a lpfp sensor. But it doesn't describe where the feedback is coming from on how the EKPS knows what voltage to apply to the fuel pump.

Exactly. Which begs the question, what in the world is the EPK trying to figure out on the load side of power out? if the EPK for the e89 is the same part as the E90 (which TIS seems to indicate that I have not check part numbers) the E90 does it with the lpfp sensor, not by measuring load on the EPK power out circuit. Mystery to me ...

Time to ask a few other E89 heavies to weigh in. @NoQuarter and @RobbiZ4 ... and even though not Z4, @bahn ... thoughts on this thread?

Filippo

 

[fmorelli]

Bump. Surprised no one has come back with more on this?

Filippo

 

[Ace718]

Exactly. Which begs the question, what in the world is the EPK trying to figure out on the load side of power out? if the EPK for the e89 is the same part as the E90 (which TIS seems to indicate that I have not check part numbers) the E90 does it with the lpfp sensor, not by measuring load on the EPK power out circuit. Mystery to me ...

Time to ask a few other E89 heavies to weigh in. @NoQuarter and @RobbiZ4 ... and even though not Z4, @bahn ... thoughts on this thread?

Filippo

I was reading through the technical docs for the N63TU and I was wondering the same thing. It also doesn't have a LP sensor so I have no idea how it determines to modulate LPFP output. Could it be that it determines this information based on an algorithm using rail pressure vs injector duty cycle/injection time and comparing that to what it expects it to be? Just a wild guess as I'm also puzzled.

 

[Ace718]

@jyamona Can you enlighten us mortals on how this witchcraft works?

 

[sleet142]

I would imagine that it had to use the rail pressure in this case. I'm interested in Jyamona's response.

 

[jts1981]

I have a minor update since running the larger wire to the 525 + 30a fuse.

Before the wire and fuse change I would get a fuel pump code on boost, and it would linger until cleared via MHD.

What I've noticed with the update is that the fuel pump code will only show up under boost where the ekp demands more current which brings more heat. The code will go away by itself once the ekp cools down. The cool down is quick, say I did a single pull on a 10 mile trip, shut the car down and I'll see a code. Restart the car a few minutes later and no codes, car drives smooth as before. Note this is only on the drive, MHD I'll have a shadow code. I find it interesting that the codes are only triggered under boost, when the ekp is running hot and drawing more current, but once ekp cools down the code seems to be resolved.

Anyways I'm looking to reprogram the ekp as mentioned on other forums to accept a higher voltage. I think/ hope this will fix it on the software side. I'm wondering if VTT or Vader could provide an option for a billet ekp cover with heatsink. I think that would cover the software and hardware limits. I also need to go back down to a 25a fuse which seems to the physical limits as someone mentioned earlier. Judging by my friend with a 525 running much higher boost + PI that only blew a fuse once I think the updates mentioned above should be sufficient for my needs.

Any thoughts?

 

[sleet142]

Sorry to leave you hanging on this. I get a shadow code (fuel pump plausibility) with the rewire, similar to most that upgrade to a stage 2 pump.

To protect the wire from over-heating/melting, going back to a 25a fuse makes sense.

I'm not sure that reprogramming the module to accept a higher voltage would be a fix. I'm thinking that reprogramming the voltage is referencing the output of the ekp so that it can drive the fuel pump harder, not an input voltage tolerance level.

Maybe you should consider going to a walbro 450 and the stock wiring so that the current draw from the pump is back within tolerance of the stock fuse and hardware. This would be my advice from a forum troubleshooting standpoint.

Otherwise you could try what I did with a MSD solid state relay instead of the relay that you currently tried.

 

[jts1981]

Thanks for the input sleek142. Unfortunately the solid state relay won't work for the e89, since we don't have an lpfp sensor. Thats why we want to reprogram the ekp to accept high voltage, but still with in spec as per a document some one shared earlier. Hopefully reprogramming, new wire, and 25a fuse will do the trick.

Oh, I got the idea for reprogramming based on another n54 forum and members seem to have positive results.

in regards to the 450 pump I've been told that the e89 performs at a similar output so no real gains here. I wonder if the ekp is holding the 450 back somehow, since there is not actually lpfp sensor to direct it? idk...I'm clueless about this stuff so I'm scouring any forum I can.

 

[sleet142]

@jts1981 Have you got any further with this?

 

[jts1981]

@jts1981 Have you got any further with this?

Yessir! well..kind of...

One of my friends tried to put me in contact with some one that could code it in my area, but that fell through.

Then I reached out to my other friend in NJ and he can also do it, but scheduling proved to be difficult.

Final solution was I bit the bullet and picked up the BPM4 from Evolution of Speed. Its not cheap but at least I know its over built for my end use and I won't have to worry about my lpfp/ ekp moving fwd. Mike was great to work with and very helpful. He had everything in stock and shipped right away.

Now its sitting in the corner of my living room waiting to get slapped in, which hopefully will happen next Wed, or Fri.

 

[Jeffman]

Yessir! well..kind of...

One of my friends tried to put me in contact with some one that could code it in my area, but that fell through.

Then I reached out to my other friend in NJ and he can also do it, but scheduling proved to be difficult.

Final solution was I bit the bullet and picked up the BPM4 from Evolution of Speed. Its not cheap but at least I know its over built for my end use and I won't have to worry about my lpfp/ ekp moving fwd. Mike was great to work with and very helpful. He had everything in stock and shipped right away.

Now its sitting in the corner of my living room waiting to get slapped in, which hopefully will happen next Wed, or Fri.

Can’t wait for your review!

 

[jts1981]

Its going in today. We just need to run a line or 2 and we should be good to go.

Just want to take a second to say Mike from Evolution of Speed has amazing customer service. He was very helpful answering all my questions regards the benefits, time frame, and he even called me back with a few minutes after I emailed him this morning when mechanic had a question on the install.

Here is another little tid bit. I was experiencing break up around 4-5k and had a few misfires. We swapped plugs from 6 to 1, but then had a misfire on 2 and 5 along with a Vanos code...very strange. We replaced the Vanos and a week later the other Vanos popped up. We changed that and the car has been running fine since, except for the break up. Its a shot in the dark but we're speculating that maybe the ekp is cutting fuel since we're getting a fuel pump code at the same rpm. Its literally smooth pull to 4-5k...break up....fuel pump code.

Hopefully this will be resolved with the new unit. If not its back to the basics with chasing down plugs or coils.

Will keep you posted.

 

[jts1981]

UPDATE!!!

ladies and gentlemen I think we did it.

The new unit works like a charm, smooth idle, power is smooth, the break up are 4-5k seems to be gone, no codes. I think our suspicions about the oem ekp cutting fuel pump due to heat/draw/ whatever to protect itself was in the right direction. Car feels smoother and stronger so I suppose the 525 is now allowed to operate properly. I did a few pulls and no codes, hiccups, breakups etc.

I'll need to log to get the whole story but at this point I'm very happy with the purchase. Install was straightforward, a bit cumbersome for the e89 since we had to run a wire to the pump which meant dropping the exhaust.

Would definitely recommend the EOS BPM4 ekp replacement if you plan to run a 525 pump.

 

[sleet142]

Sweet man! I didn't know about this product when I did my rewire. Although, I think this is a great solution to E89 cars not having a lpfs if someone wanted to run a Walbro 525... and pay that price tag .

You will like the 525 as well. Mine hasn't skipped a beat at 18psi on pump.

https://datazap.me/u/sleet142/2019-after-trip-north?log=0&data=3-15-24

 

[N54rsenal]

I have a 2010 E90 335i will running a Walbro 525 itself in the factory bucket work without issues such as frying the Factory EKP?
I already get a shadow code (fuel pump plausibility) with my stock fuel pump at 79K. During every pull its around ~50PSI.
A single Walbro 525 Hellcat Fuel Pump is 700HP Capable on E85 that's perfect as a single LPFP.
Why does Fuel-it offer a Walbro 525 upgrade option on their stage 2 LPFP if it doesn't work?

Ideally I would buy the EOS BPM4 EKP replacement for X2 525's and avoid using X2 450's+Hobbs switch which would clean things up, but im only on stock turbos it would be a waste.