[E85 335]

Hello gentlemen,

Recently I have decided to remove the JB4 and BMS PI controller and have a Custom Wedge MHD map running 98ron at present. Having issues where the lpfp dips.

Here is my datazap log:

https://datazap.me/u/murdo81/3rd-gea...og=0&data=3-20

We now have the secondary fuel pump connected via a 15 psi Hobb's switch and logs are showing it switching on.

Now we are still looking into why the primary fuel pump is dropping well under 40 psi which is throwing a low pressure code, being a upgraded fuel pump and the car only running on pump fuel it should hold higher pressure then that?

We have visually inspected fuel pumps, buckets, lines ect and all seem to be fine.

So far in testing, we have disconnected the primary and ran only the secondary fuel pump to see what would happen to the fuel pressure. Well it Stays above 70 psi which would rule out cracked, broken or blocked lines, fitting ect as the secondary pump works on the same lines correct ?

We have also checked the volts to the ekpm2, which read +12v. From the ekpm2 to the pump we are seeing volts 6v-13v, I understand it's PWM controlled but am unsure if that's within spec. I will check on our shop 335i to verified the readings.

At this stage I suspect it's the ekpm2 or the primary fuel pump. We have a new ekpm3 (Updated version) on it's way so we can do further testing.

If you have any insight or ideas to help resolve this issue would be greatly appreciated.

Thanks

[tawfeeqh]

Hey mate

Interesting I'm experiencing a very similar issue where my LPFP is dropping off to ~50 psi when under load over 5000 rpm. As soon as I let off the peddle it pops back up to ~80 psi.

Car is similar setup to yours MHD flash only, Upgraded twins, Stage 3 pumps, PI with hobb switch and AI6 SS controller. Although logs below are running 100% e85.

3rd gear log

https://datazap.me/u/tawfeeqh/lpfp-i...22&zoom=19-160

1st, 2nd, 3rd, 4th gear logs at the drags

https://datazap.me/u/tawfeeqh/calder...zoom=2925-3090

This issue I have is intermittent and some logs are clean. I'm not going to be much help here but I was going to firstly replace the hobb switch as its a cheap part. Test the secondary fuel pump to see if its engaging, but it seems like you have done both already. I don't think its a tuning issue because logs were perfect for at least 6 months after this setup. i haven't changed the map so it has to be a pump or controller issue.

If you do find out whats going on let me know too

p.s. have sent logs to steve @ fuelit months ago but got no response or assistance from him

[E85 335]

Yeah it's a major pain in the a$$ but he has suggested that it could be the pre-filter on the passenger side of the fuel tank. They aren't cheap to replace so I'm going to replace the in order. Ekpm2 to a ekpm3 which I got for $60 then if that doesn't work replace the walbro 450 pump and if that doesn't work then the filter as it's around $300 for it.

[Montye90]

I'm a complete Noob and have workshops work on my car, but on my previous JDM model cars, when upgrading fuel pumps, re-wiring was required with larger gauge wiring to supply power to the fuel pump(s).

So reading your issues, again I am a NOOB, I see a voltage drop mentioned here - "We have also checked the volts to the ekpm2, which read +12v. From the ekpm2 to the pump we are seeing volts 6v-13v, I understand it's PWM controlled but am unsure if that's within spec. I will check on our shop 335i to verified the readings. "

Is that worth looking into?

I just googled this based on what you said...came up with "low voltage or a bad connection or ground will cause a pump to underperform, producing the same test results as if the pump were bad"

Hope this helps

[E85 335]

Originally Posted by Montye90

I'm a complete Noob and have workshops work on my car, but on my previous JDM model cars, when upgrading fuel pumps, re-wiring was required with larger gauge wiring to supply power to the fuel pump(s).

So reading your issues, again I am a NOOB, I see a voltage drop mentioned here - "We have also checked the volts to the ekpm2, which read +12v. From the ekpm2 to the pump we are seeing volts 6v-13v, I understand it's PWM controlled but am unsure if that's within spec. I will check on our shop 335i to verified the readings. "

Is that worth looking into?

I just googled this based on what you said...came up with "low voltage or a bad connection or ground will cause a pump to underperform, producing the same test results as if the pump were bad"

Hope this helps

Cheers for your input. The stage 3 came with different sized wiring which I have used. Never had any issues until just recently. As soon as I pulled out the JB4 I now have these issues. Been asking Steve from fuel-it but his responses have been a bit veage.

[JB4-335]

Moral of the story "Never remove a JB4 tune from an N54".

Sorry I know that wasn't much help.

Hope you get it sorted out.

[E85 335]

Originally Posted by JB4-335

Moral of the story "Never remove a JB4 tune from an N54".

Sorry I know that wasn't much help.

Hope you get it sorted out.

Bahaha it just suppressed the issues having it in. Thats the moral.. Way smoother having mhd

[vtl]

Have you seen your AFRs? The fuel pressure problem is just a symptom of a larger issue.

Your Afrs are flat at 10.28, and the STFTs are maxxed at -34%!. Flat 10.28 means its probably a lot richer than that, as the sensors don't detect anything more. Getting black smoke out the exhaust on a pull?

Looks like your PI is just dumping fuel into the engine, which is dipping your fuel pressures. This causes AFRs to go rich, DME is trying to take out all the fuel but of course has no control over the PI.

Dunno why your tuner/workshop couldn't work that out vs some a guy on the internet.

Oil change asap btw, as running this rich, the fuel has probably diluted your oil

[Brule]

That’s running very rich.
Should be around 12 for pump fuel.
Stat should bounce around not pegged at certain amounts.

Did you notice the previous tunes afr?
When I had stuffed o2 sensors one bank was pumping fuel in all the time but you have both banks Taft maxing out.

No signs of major air leak?

[E85 335]

Originally Posted by Brule

That’s running very rich.
Should be around 12 for pump fuel.
Stat should bounce around not pegged at certain amounts.

Did you notice the previous tunes afr?
When I had stuffed o2 sensors one bank was pumping fuel in all the time but you have both banks Taft maxing out.

No signs of major air leak?

I have all my logs at this address

https://datazap.me/u/murdo81

[E85 335]

Originally Posted by vtl

Have you seen your AFRs? The fuel pressure problem is just a symptom of a larger issue.

Your Afrs are flat at 10.28, and the STFTs are maxxed at -34%!. Flat 10.28 means its probably a lot richer than that, as the sensors don't detect anything more. Getting black smoke out the exhaust on a pull?

Looks like your PI is just dumping fuel into the engine, which is dipping your fuel pressures. This causes AFRs to go rich, DME is trying to take out all the fuel but of course has no control over the PI.

Dunno why your tuner/workshop couldn't work that out vs some a guy on the internet.

Oil change asap btw, as running this rich, the fuel has probably diluted your oil

I dont know anything much about cars mate. I just pay the $$ lol. I have only put the PI on yesterday. Sorry should of mentioned that Ken hasnt accounted for that in a revised map. Havent seen any black smoke yet. The other logs before PI install show that afr's are fine but still having the drops.

https://datazap.me/u/murdo81

[Brule]

Originally Posted by DAT335

Bahaha it just suppressed the issues having it in. Thats the moral.. Way smoother having mhd

You will Never go back.

[Brule]

So you have had your car tuned previously and it was fine.

Now you have added Pi and it’s rich as?

[vtl]

Originally Posted by DAT335

I dont know anything much about cars mate. I just pay the $$ lol. I have only put the PI on yesterday. Sorry should of mentioned that Ken hasnt accounted for that in a revised map. Havent seen any black smoke yet. The other logs before PI install show that afr's are fine but still having the drops.

https://datazap.me/u/murdo81

In order to get this car dialed in, fix one problem at a time, starting from the most serious.

You don't want to hydrolock your engine from the PI just dumping in fuel like that. Ignoring that issue and focusing on something else is madness.

[E85 335]

Originally Posted by Brule

So you have had your car tuned previously and it was fine.

Now you have added Pi and it’s rich as?

So previously had jb4 with pi connected. Removed both and decided to go just mhd. Contact Ken from wedge for a custom map. When he did the map I didnt have the hobb switch for the stage 3 pump setup and had no PI when ken did the first few maps. In the meantime ken gave me a few maps without these connected. the PI controller was BMS with i swapped out to the split second only yesterday and add the hobb switch. The issue is the stage 3 without the hobb switch when doing the the logs showed a drop in the lpfp into the 30's. My understanding is that it shouldn't be as it should run the same as a stage 2 and should drop that low.. Lets ignore the first 2 logs with port injection and hobb switch being connected as I have disconnected it for the time being. It still brings me to thinking its the primary fuel pump stuffed or the ekpm2 is stuffed. Oh I also found that my o2 sensor pre catt bank2 somehow loosened which was wierd but is now tighten back up.

[E85 335]

Originally Posted by vtl

In order to get this car dialed in, fix one problem at a time, starting from the most serious.

You don't want to hydrolock your engine from the PI just dumping in fuel like that. Ignoring that issue and focusing on something else is madness.

So found out what the issue was. Was the external fuel-it FPR was turned up to high. Idle was sitting at 75psi and then lowered it to 65psi and now dont have the issues of the lpfp dropping into the 3o's like before..