[Ingeniator]

Originally Posted by 135Pats

Hey guys,

Some updates here, would love your input. Still running a 20 amp fuse as there was a kink in a fuel line, which to me would appear to be the culprit. HOWEVER- the car is still demanding the same type of fuel PSI at idle, high 80s which it pegs very consistently. At this point the only thing I can think of is a bad fuel regulator/filter unit, but wouldn't that lead to less pressure, not more? I have no idea what would cause the car to have such poor control over fuel PSI low pressure. Again, nothing exotic about the FFTEC pump. Below is the latest, all taken from last night.


1. Cold start behavior. As you can see, it pegs high 80s instantly and doesn't really budge.
http://www.datazap.me/u/135pats/cold-start

2. Just cruising under light load and throttle. Similar story, PSI pegs around 87-89PSI stays there.
http://www.datazap.me/u/135pats/0-50-cruising

3. 3-4-5 pull with the same results before. Things look OK fueling wise to me WOT, suppose trims could be tighter but the car is still adapting with only 50 miles since the last reset.
http://www.datazap.me/u/135pats/3-4-5


The car threw no codes at all but I did find a p2c7c when I got in the car, so i'll be replacing the post cat o2s soon. Doubt that's at all the issue here though.

Pats,

This is an odd problem. Looking at the logs I would say that the voltage regulation is working but it is possibly offset. I'm wondering if it is not your vvc(variable voltage control) is staying above 3 at no load. The pump adjusts output based on the voltage received. If your fuel pump control module is faulty it could think it is giving minimum voltage but it is running higher. I would confirm voltage to the pump at idle is ~3V. If that is the case I would try examining your fuel filter and pressure regulator as that is the only option left.

[135Pats]

Originally Posted by Ingeniator

Pats,

This is an odd problem. Looking at the logs I would say that the voltage regulation is working but it is possibly offset. I'm wondering if it is not your vvc(variable voltage control) is staying above 3 at no load. The pump adjusts output based on the voltage received. If your fuel pump control module is faulty it could think it is giving minimum voltage but it is running higher. I would confirm voltage to the pump at idle is ~3V. If that is the case I would try examining your fuel filter and pressure regulator as that is the only option left.

Thx for the feedback

OK here's a dumb question- how do I measure voltage at the pump? I'm a complete electronics noob.

I'm starting to think this pump just doesn't play nice in my car, for whatever reason. Probably going to try a 255 traditional inline setup.

I have a hard time believing the regulator just failed out of the blue.

[Ingeniator]

Originally Posted by 135Pats

Thx for the feedback

OK here's a dumb question- how do I measure voltage at the pump? I'm a complete electronics noob.

I'm starting to think this pump just doesn't play nice in my car, for whatever reason. Probably going to try a 255 traditional inline setup.

I have a hard time believing the regulator just failed out of the blue.

I also have a hard time believing it is the regulator. It more looks in your logs like they are fighting each other. If you have a multimeter. Cheap one works. put it on 20v mode. with the red lead in the voltage slot. Then you need to find the correct pin for power. Place your red lead on one of the pump wires then the black on a chassis ground in the area. If you have voltage it is the right one if not try the other wire. As far as I can tell from this thread vishnu N54 fuel system research. It is a two wire supply. If you are getting more than 3v at idle that is more than likely your issue. I'm not sure how the inline gets fed. But I would assume it is from the same voltage feed and not a switched 12v supply from elsewhere.

[135Pats]

Originally Posted by Ingeniator

I also have a hard time believing it is the regulator. It more looks in your logs like they are fighting each other. If you have a multimeter. Cheap one works. put it on 20v mode. with the red lead in the voltage slot. Then you need to find the correct pin for power. Place your red lead on one of the pump wires then the black on a chassis ground in the area. If you have voltage it is the right one if not try the other wire. As far as I can tell from this thread vishnu N54 fuel system research. It is a two wire supply. If you are getting more than 3v at idle that is more than likely your issue. I'm not sure how the inline gets fed. But I would assume it is from the same voltage feed and not a switched 12v supply from elsewhere.

OK that vaguely makes sense in my head, I do not have a multimeter but can get one tomorrow. I'm really starting to lean towards this pump hating my car, every "problem" i can cook up is becoming pretty far fetched, as in- no one has ever had this happen far fetched. Then again plenty of people are running the 455 inline, with no issues. I've replaced just about every part of the fueling system at this point except the regulator and the pump control module. And IDK if i've ever seen an instance of those failing.

Thanks for the help

[AUbeast86]

I ended up replacing my 455 with the 255 kit SteveAZ is offering along with a new OEM bucket and that solved my problem.

[135Pats]

Originally Posted by AUbeast86

I ended up replacing my 455 with the 255 kit SteveAZ is offering along with a new OEM bucket and that solved my problem.

I have a feeling the same thing will happen to me. Good thing this pump was a good value buy. Oh wait, not in the least.

[135Pats]

OK so here is where things currently stand. I’ve added in a 3D scalar to account for E60, that has alleviated the problem in all situations except one. When idling, starting, cruising, or even giving a good amount of load, the car is fine and hits low 70s PSI without issue.

However- when I go WOT or give it a lot of load, fuel pressure does not return to its requested PSI and stays in the high 80s. If I pull over and re-start the car, it returns to normal. It is very, very odd behavior and I cannot explain it. I’ve attached logs that display what I’m talking about. SteveAZ’s pump should come in today so if it’s warm out, I may swap pumps over the weekend to see if that remedies it.


http://datazap.me/u/135pats/e55?log=0&data=1-20-21

[Tony@vargasturbotech]

Originally Posted by 135Pats

OK so here is where things currently stand. I’ve added in a 3D scalar to account for E60, that has alleviated the problem in all situations except one. When idling, starting, cruising, or even giving a good amount of load, the car is fine and hits low 70s PSI without issue.

However- when I go WOT or give it a lot of load, fuel pressure does not return to its requested PSI and stays in the high 80s. If I pull over and re-start the car, it returns to normal. It is very, very odd behavior and I cannot explain it. I’ve attached logs that display what I’m talking about. SteveAZ’s pump should come in today so if it’s warm out, I may swap pumps over the weekend to see if that remedies it.


http://datazap.me/u/135pats/e55?log=0&data=1-20-21

I think you are really obsessing over something that isn't affecting anything. I have seen the shop car exhibit the same behavior, the way the fuel system is controlled leaves it completely up to the DME to use voltage to regulate the pressure. If the car is running great and fuel mileage isn't way out of line then I would just leave it alone

[135Pats]

Originally Posted by Vargasturbotech

I think you are really obsessing over something that isn't affecting anything. I have seen the shop car exhibit the same behavior, the way the fuel system is controlled leaves it completely up to the DME to use voltage to regulate the pressure. If the car is running great and fuel mileage isn't way out of line then I would just leave it alone

I would be inclined to agree but I still would like to better understand the behavior, delivering high 80s PSI only in this one set of circumstances is not normal. It’s blown the fuel fuse twice, so clearly it’s over driving things and/or creating too much heat. I just have a tough time believing this is optimal or normal….But I hear what you are saying. And you’ve been very helpful on this front, I appreciate that man.

[Tony@vargasturbotech]

Originally Posted by 135Pats

I would be inclined to agree but I still would like to better understand the behavior, delivering high 80s PSI only in this one set of circumstances is not normal. It’s blown the fuel fuse twice, so clearly it’s over driving things and/or creating too much heat. I just have a tough time believing this is optimal or normal….But I hear what you are saying. And you’ve been very helpful on this front, I appreciate that man.

Yeah I forgot about the fuse issue. I would suggest changing the EKP fuel controller that is in the rear kick panel that regulates the voltage to vary pressure. I have heard of those going bad from quite a few people. They are not too expensive

[Ingeniator]

Originally Posted by Vargasturbotech

Yeah I forgot about the fuse issue. I would suggest changing the EKP fuel controller that is in the rear kick panel that regulates the voltage to vary pressure. I have heard of those going bad from quite a few people. They are not too expensive

Pats,

Did you ever get the chance to check voltages?

[135Pats]

Originally Posted by Vargasturbotech

Yeah I forgot about the fuse issue. I would suggest changing the EKP fuel controller that is in the rear kick panel that regulates the voltage to vary pressure. I have heard of those going bad from quite a few people. They are not too expensive

Yea I think that is the next step for sure. Just need to find a PN I know visually what you are describing.

Originally Posted by Ingeniator

Pats,

Did you ever get the chance to check voltages?

Have not…I need to buy a multi-meter for sure.


It's just odd to me that it can properly regulate LPFP PSI just fine, until you let off WOT or near WOT. Then it loses all ability to regulate it until the car is restarted. Bizarre...

[Ingeniator]

Originally Posted by 135Pats

Yea I think that is the next step for sure. Just need to find a PN I know visually what you are describing.


Have not…I need to buy a multi-meter for sure.


It's just odd to me that it can properly regulate LPFP PSI just fine, until you let off WOT or near WOT. Then it loses all ability to regulate it until the car is restarted. Bizarre...

Yeah I would use the voltage at idle to determine if your having issues with the EKP. If you were ambitious. I would run a wire tap from the right pump wire into the cabin. Being extremely careful to not ground it out. Then live monitor the voltage while doing a pull. If the EKP is bad it should be obvious in the voltage.

01 Control unit for fuel pump 1 09/2008 16147229173 $270.47

[135Pats]

Originally Posted by Ingeniator

Yeah I would use the voltage at idle to determine if your having issues with the EKP. If you were ambitious. I would run a wire tap from the right pump wire into the cabin. Being extremely careful to not ground it out. Then live monitor the voltage while doing a pull. If the EKP is bad it should be obvious in the voltage.

01 Control unit for fuel pump 1 09/2008 16147229173 $270.47

The latter idea is very smart...but somewhat terrifying. Would really need to be careful.

Thanks for the part number that is extremely helpful. I still think that fundamentally, this is an issue with the pump and not the peripheral parts. So my next step is going to be to swap in SteveAZ's 255 setup and see how the car likes it.

When all is said and done, i'll be nearly $2K dumped into the damn car just to run E60. That sucks but it's a sunk cost.

[Ingeniator]

Originally Posted by 135Pats

The latter idea is very smart...but somewhat terrifying. Would really need to be careful.

Thanks for the part number that is extremely helpful. I still think that fundamentally, this is an issue with the pump and not the peripheral parts. So my next step is going to be to swap in SteveAZ's 255 setup and see how the car likes it.

When all is said and done, i'll be nearly $2K dumped into the damn car just to run E60. That sucks but it's a sunk cost.

Since you don't have a multi meter. You could always just put the 20 bucks towards a cheap voltage gauge from the parts store. As long as the wires are taped it will be 100% safe. Run the g+ wire to the pump g- wire to chassis ground.

[Dave W.]

Multimeters are just $12 at walmart. You just need it to read DC volts so you don't need anything fancy. Even the $12 basic model will work.

[07tundra]

Originally Posted by Dave W.

Multimeters are just $12 at walmart. You just need it to read DC volts so you don't need anything fancy. Even the $12 basic model will work.

If I had what you had invested in that fftec unit I would definitely find a way to make it work Pats!

[bmwm3redblack]

Originally Posted by AUbeast86

I ended up replacing my 455 with the 255 kit SteveAZ is offering along with a new OEM bucket and that solved my problem.

where can i get SteveAZ kit 255????

Originally Posted by bmwm3redblack

where can i get SteveAZ kit 255????

You could start by reading the replies you got in the thread you started about that very topic, perhaps.

[bmwm3redblack]

Originally Posted by FCobra94

You could start by reading the replies you got in the thread you started about that very topic, perhaps.

i've checked the link and,but i can't open it

[135Pats]

Originally Posted by Dave W.

Multimeters are just $12 at walmart. You just need it to read DC volts so you don't need anything fancy. Even the $12 basic model will work.

Yea it's not a big expense, I should pick one up this weekend. Just a PITA to have to be reading voltage, but you are 100% right.

Originally Posted by 07tundra

If I had what you had invested in that fftec unit I would definitely find a way to make it work Pats!

Ugh. I agree man...Have replaced SO MANY parts trying to get this right. It's a sunk cost so I want to make it work. But I just opened up SteveAZ's inline kit, and it is NICE. Looks very well thought out. I'll end up swapping the pumps out very likely just to rule out another hardware part. At that point though, honestly i'm running out of parts to replace. At this point it's just the pressure regulator/filter, and the control module. So come hell or high water i'll get this working.

[cwarren]

pats just started having a similar problem car idles mid 80's will jump to 100 and bounce around at wot . fuel trims look fine too just as a fyi this is completely stock lpfp