[SOLVED] Can't Hold Fuel Pressure

[Brado]

That could be the PRV opening up just enough to let a *drop* of fuel out.

Edit: The camshaft runs at 1/2 crank RPM, has THREE lobes to drive the HPFP, and has VVT so who knows when it's going to push the piston forward or at what rate (faster if advancing, slower if retarding), etc.

Also assuming you were cranking it here, correct? If so, then the spill valve and check valve come into play; yet more variables. Get the car hot, in a controlled environment (where ambient is say 70-80F and then see how it acts. Other than that, even 1750 PSI you see here is actually fine.

That screenshot of the datalog was from a WOT 4th gear pull. I'm okay with it cracking early at ~1790psi, but dropping into the 1400-1500s is where I start to get a bit concerned.

I'll retry the PRV test on a hotter day and see if my results are different.

 

[Enki]

What turbo and intake are you running?

 

[Brado]

What turbo and intake are you running?

BNR S3 and HTP 3" intake.

I know you've mentioned that the HPFP does most the work, however is it all possible that the in-take pump simply isn't providing sufficient volume at these higher RPMs? I unfortunately don't have a kit to test the ITFP volume or a separate gauge to measure the ITFP at WOT.

 

[Enki]

I've pulled down and looked at all the logs you uploaded; please tell me this tune isn't a final tune; I don't remember exactly what stock timing was at 6k RPM, but I want to say it was around what you're running (7 degrees). Normally, a car with a pump gas tune on big turbo will be somewhere closer to double that, or at least 10 deg.

Some other notes:
1. I'd like to see a short cruising log (highway speeds flat road and nobody in front of you, 10-20 seconds under these conditions is fine)

2. Remove the following PIDs from your logging:
Fan Duty (%)
HPFP Des. Press. (psi)
HPFP Sens. Volt. (V)
Throttle Duty Cyc. (°)
Throttle Position (%)

3. While it's possible your ITFP (or reg) is going out, it's more likely that the sock filter is dirty and restricting flow; it's something to look into, but hard to say if your pump is actually bad without throwing a gauge on it.

 

[Brado]

I've pulled down and looked at all the logs you uploaded; please tell me this tune isn't a final tune; I don't remember exactly what stock timing was at 6k RPM, but I want to say it was around what you're running (7 degrees). Normally, a car with a pump gas tune on big turbo will be somewhere closer to double that, or at least 10 deg.

The 91 tune is a final revision, yes. My E30 tune is about ~15 degrees of timing. I did let my tuner know I wanted this engine to last and he's let me know the 91 tune is conservative. If it helps, I found a stock-ish WOT log from here.

Some other notes:
1. I'd like to see a short cruising log (highway speeds flat road and nobody in front of you, 10-20 seconds under these conditions is fine)

I've attached datalog416 which contains some highway crusing among other things.

2. Remove the following PIDs from your logging:
Fan Duty (%)
HPFP Des. Press. (psi)
HPFP Sens. Volt. (V)
Throttle Duty Cyc. (°)
Throttle Position (%)

Can do.

3. While it's possible your ITFP (or reg) is going out, it's more likely that the sock filter is dirty and restricting flow; it's something to look into, but hard to say if your pump is actually bad without throwing a gauge on it.

Regarding the sock in the fuel tank, I don't suppose there's an additive that would help alleviate some of this build up to even troubleshoot for improvement? Otherwise, short of dropping the tank or cutting the car, I can try a fuel volume test. Haven't done one before, but it was recommended to me.

 

[Brado]

What's wild to me is that this issue is intermittent. I managed to get this solid pull onto the freeway without any issues. Coming back the other direction, the issue happened again.

These were tonight, so they actually have extra PIDS because I was curious. Don't crucify me!

 

[Enki]

How much fuel is left in the tank, and whats your ethanol %?

Since you have tunes for two types of fuel, I'd be willing to bet that the tank has been stripped of garbage by the corn and it's now rolling around in your tank fucking up the works. Or your fuel pump/reg is dying. If you're going to check it out, you might as well get a new reg and filter anyways, as I don't think they were super expensive.

Also the log you linked (stock turbo, stock tune so much lower load) was making double your timing. I'm reasonably sure you basically paid for a MAFCAL on that 91 tune, and your E30 tune is well beyond "safe" since you're basically running pump gas timing on corn.

Edit: Who's the tuner?

 

[Brado]

How much fuel is left in the tank, and whats your ethanol %?

I've been running 91 since this issue happened, so I would imagine very little.

Since you have tunes for two types of fuel, I'd be willing to bet that the tank has been stripped of garbage by the corn and it's now rolling around in your tank fucking up the works. Or your fuel pump/reg is dying. If you're going to check it out, you might as well get a new reg and filter anyways, as I don't think they were super expensive.

I've been ethanol tuned for years and switch off periodically, so it's definitely possible there's shit in the tank. I saw the AEM drop in replacement pump online and it comes with a filter as well. Do you have a link to the regulator? If I have to drop the tank I want to do it once and replace all the parts in there.

Also the log you linked (stock turbo, stock tune so much lower load) was making double your timing. I'm reasonably sure you basically paid for a MAFCAL on that 91 tune, and your E30 tune is well beyond "safe" since you're basically running pump gas timing on corn.

Edit: Who's the tuner?

You know I'm on Drama. We've gotten into this before and I would really like to avoid this again.

Regarding the timing, and forgive me because I'm not a tuner, why is that the big indicator? I've been running this 8 degree timing tune since my first ever tune, and have been enjoying the power. I did get curious and I pulled a datalog of the tune the car came with (datalog167), from the same tuner. It used more timing, but the power was a bit lower than my latest 91 tune.

I also attached my last known good E30 WOT log in case you want to look through that.

(If Virtual Dyno is not a good resource, just let me know because it's all I have.)


Again, I'd really like to avoid a battle against my tuner because I personally have been very happy with how my car drives when it's running 100%, and even if that's at the sacrifice of power left on the table, I just want to get it back to that point first.

 

[Enki]

Do you have a link to the regulator? If I have to drop the tank I want to do it once and replace all the parts in there.

Jim Ellis Mazda parts can help you out there. I don't remember the part number but it's a little guy that kind of clips in to the basket.

You know I'm on Drama. We've gotten into this before and I would really like to avoid this again.

You don't honestly believe I remember every detail of every issue I give advice on do you? As far as I was concerned going into this, you were new here and just bought the car from someone. Hell, I'm only even in this thread because you pinged me back on page 1.

Regarding the timing, and forgive me because I'm not a tuner, why is that the big indicator? I've been running this 8 degree timing tune since my first ever tune, and have been enjoying the power.

Believe it or not, too little timing can be just as bad as too much timing. You can burn valves, cook oil in the turbo, all kinds of bad shit.

I did get curious and I pulled a datalog of the tune the car came with (datalog167), from the same tuner. It used more timing, but the power was a bit lower than my latest 91 tune.

I just peeked at that log and if the intake hasn't changed (it looks like it might have) then it's running leaner with less airflow across the MAF and is running into knock. Also the BATs were higher but I'm assuming you swapped intercoolers since then, perhaps from TMIC to FMIC? That would make sense comparing your logs from tonight vs the old one. That would certainly explain the additional flow at the lower boost and reduced BATs.

Boost vs Flow vs Timing vs Octane is a delicate balance that takes a long time to get right; not only is every engine within a platform different, every platform is different too. Never trust someone that only tunes Subies and BMWs to tune your Mazda, as an example.

If Virtual Dyno is not a good resource, just let me know because it's all I have.

Nope VDyno is just fine.

Again, I'd really like to avoid a battle against my tuner because I personally have been very happy with how my car drives when it's running 100%, and even if that's at the sacrifice of power left on the table, I just want to get it back to that point first.

As long as you know, that's what matters.

 

[Brado]

Jim Ellis Mazda parts can help you out there. I don't remember the part number but it's a little guy that kind of clips in to the basket.



You don't honestly believe I remember every detail of every issue I give advice on do you? As far as I was concerned going into this, you were new here and just bought the car from someone. Hell, I'm only even in this thread because you pinged me back on page 1.



Believe it or not, too little timing can be just as bad as too much timing. You can burn valves, cook oil in the turbo, all kinds of bad shit.



I just peeked at that log and if the intake hasn't changed (it looks like it might have) then it's running leaner with less airflow across the MAF and is running into knock. Also the BATs were higher but I'm assuming you swapped intercoolers since then, perhaps from TMIC to FMIC? That would make sense comparing your logs from tonight vs the old one. That would certainly explain the additional flow at the lower boost and reduced BATs.

Boost vs Flow vs Timing vs Octane is a delicate balance that takes a long time to get right; not only is every engine within a platform different, every platform is different too. Never trust someone that only tunes Subies and BMWs to tune your Mazda, as an example.



Nope VDyno is just fine.



As long as you know, that's what matters.

When my car is running normal and I've got my tunes all finalized, I'll shoot you a message and see what you think. I'd like to get to that point for now, but wouldn't mind diving into it again when I can.

Since I've purchased the car, the only differences are new OEM motor, BNR S3 revision update, and DTP exhaust manifold with external wastegate. I've been FMIC since I bought it, 3" intake, stock intake manifold, catless downpipe, etc. It's been cooler out here as well. The intake didn't change, but I fixed many a things when I purchased the car so I wouldn't be surprised if it doesn't look a bit better. Replaced the filter with a CorkSport one within the last year, too. Target AFR is 11.7 for all my tunes I've seen.

I'll check with Jim Ellis Mazda! What would you suggest next in the troubleshooting process?

 

[Enki]

Just the filter and regulator, those are relatively inexpensive so it's not really a loss if that doesn't fix it; you probably needed to do it anyways.
Easier than that is to tear down and clean the HPFP, but I think that was suggested already (I only skimmed the thread).

 

[Easter Bunny]

@Awafrican lock the thread op is tuned by dramatune and doesn't think that's a problem. Nothing else we can do here.

 

[Awafrican]

@Awafrican lock the thread op is tuned by dramatune and doesn't think that's a problem. Nothing else we can do here.

Enki might be onto something with the fuel filter... while op is strong headed about his tuner we're also strong headed about drama so let's see what come with enki's suggestion.

However yes it does seem there's some beyond safe limits going on in the tune despite the tuner saying it's "safe"

 

[Brado]

Just the filter and regulator, those are relatively inexpensive so it's not really a loss if that doesn't fix it; you probably needed to do it anyways.
Easier than that is to tear down and clean the HPFP, but I think that was suggested already (I only skimmed the thread).

Yeah I've cleaned the HPFP a few times now, even using the Redline cleaner that you suggested. If anything it helped quiet my HPFP a bit, but alas no luck on this issue.

@Awafrican lock the thread op is tuned by dramatune and doesn't think that's a problem. Nothing else we can do here.

Because it's commonly used here to handwave everything away and point to as the single fault and shut down discussion. If the car can run great on his tune, then I think it's silly "answer" to simply blame everything on the tuner, despite the car running fine on it for years.

It's extremely telling that you read my OP, still suggested I clean the spill valve despite me mentioning cleaning it and swapping it, hibernate while Enki helps me actually troubleshoot and then jump right back in on the hate wagon for Dramatune. Be productive.

Enki might be onto something with the fuel filter... while op is strong headed about his tuner we're also strong headed about drama so let's see what come with enki's suggestion.

However yes it does seem there's some beyond safe limits going on in the tune despite the tuner saying it's "safe"

I appreciate this take, as these forums are indeed an echo chamber. If someone could prove that it was my tune, I'm all ears. I see the car is requesting 1749psi per my tune, and my car isn't meeting it. I am not a tuning expert, but if the tuner is requesting more fuel than my car is putting out, I can't personally see how it's the tuner.

My tuner was the one who brought this issue to my attention and said we couldn't proceed until it was fixed.

This is exactly why I said the following:

Again, I'd really like to avoid a battle against my tuner because I personally have been very happy with how my car drives when it's running 100%, and even if that's at the sacrifice of power left on the table, I just want to get it back to that point first.

 

[Easter Bunny]

It's extremely telling that you read my OP, still suggested I clean the spill valve despite me mentioning cleaning it and swapping it, hibernate while Enki helps me actually troubleshoot and then jump right back in on the hate wagon for Dramatune. Be productive.

you first post in no way specified that you cleaned the spill valve, you use dramatune so obviously you are stupid enough that i need to spoon feed you that cleaning the spill valve is part of cleaning the HPFP

everyone hand waves driveability issues on dramatunes because they suck and there is no sense in trying to trouble shoot when the single most important part of making your car run well has been modified by a hack who has no idea what they are doing.

just because it is worth reminding everyone, this "tuner" that you choose to use has stated in writing that nothing was wrong with a tune to a customer. this person was inquiring as to why he was making less power on the tune with a 3076 vs stock.

all that said I don't think that your issue is tune related, based on the odd pressure curve you have it looks like a leak somewhere to me.

 

[Enki]

When I look at logs, I tend toward one of two methods of approach:
1. I look for things that would line up with specific symptoms/issues
2. I look at them generally for anything that stands out

You can guess what approach I wound up taking with your logs, since the issue was sporadic. To be completely transparent here, If I see bullshit in *any* tune I call it out, don't for a second think that it's just Drama that I shit on. In fact, I've even called myself out on some things by stating (in the thread specific to Dramatune) that some of the things I do in my car I would *never* do in a customers car. I *can* do these things because I know my driving habits and I also know my engine.

Back on topic:
If you've cleaned and inspected the HPFP and there's no galling apparent on the internals then it's likely your filter and/or reg that's to blame, but probably more the filter. If you know anything about positive displacement pumps you'd know that so long as they can be "fed" (volume of fuel not pressure) they will output the desired pressures asked of them. I would be willing to put money on a return style fuel pressure regulator at the HPFP supplying 5 psi would be enough to see normal operating pressures at the rail. Hell, most carburetors only run off of 7 PSI.

Edit:

all that said I don't think that your issue is tune related, based on the odd pressure curve you have it looks like a leak somewhere to me.

It *could* still be PRV but that is way more intermittent than the usual PRV failures I've seen. It would make more sense if the "randomness" could be attributed to fuel rail temperature or something else that might correlate to a feasible cause.

 

[Brado]

Alright, spoke with Jim Ellis Mazda (SUPER helpful) and my local Speed3 guy, who recommended replacing the retaining ring along with the seal as well.

Here are some part numbers:
AEM 50-1220 Fuel Pump (includes filter)
L3M8-13-280 ITFP Regulator
BN8F-42-167 Retaining Ring
BN8F-42-166 Fuel Gasket
LFB6-13-ZE1 Fuel Pump Filter (heard some of the aftermarket ones aren't great, cheap enough insurance)

If you've cleaned and inspected the HPFP and there's no galling apparent on the internals then it's likely your filter and/or reg that's to blame, but probably more the filter. If you know anything about positive displacement pumps you'd know that so long as they can be "fed" (volume of fuel not pressure) they will output the desired pressures asked of them. I would be willing to put money on a return style fuel pressure regulator at the HPFP supplying 5 psi would be enough to see normal operating pressures at the rail. Hell, most carburetors only run off of 7 PSI.

This is the condition of the internals. The piston looks alright, but the center of the shaft is worn. CorkSport has not told me anything concerning about these, but I do have other OEM internals I could swap to test in troubleshooting. I can tell they definitely get hot.

It *could* still be PRV but that is way more intermittent than the usual PRV failures I've seen. It would make more sense if the "randomness" could be attributed to fuel rail temperature or something else that might correlate to a feasible cause.

Man that would suck. I've tried a total of 4 different PRVs and haven't had much luck. 3 I believe to be working, one known bad. I have a friend who's going to get a similar PRV test to mine so I can compare. Everything I've seen online indicates the pressure should rise much quicker, and the fact that mine drops off so suddenly and only was able to reach 1791psi after a hard drive and throttle blip really has me wondering.

 

[Enki]

The pic you've posted shows wear where the collar seals are. If this set of internals is too big, that could be an issue; usually the galling I talk about is on the big end where it's actually a metal to metal surface lubricated entirely by fuel (or in best case, Redline injector cleaner which I think is a much better lubricant).

@CorkSport - Derrick how do these look to you?

 

[Brado]

you first post in no way specified that you cleaned the spill valve, you use dramatune so obviously you are stupid enough that i need to spoon feed you that cleaning the spill valve is part of cleaning the HPFP

Fuel system wise, I've got:

• OEM HPFP

These parts have all been installed new/serviced within the past few years.

I also took apart the 1yr old pump and "cleaned" the nothing inside

The spill valve is part of the HPFP assembly.

everyone hand waves driveability issues on dramatunes because they suck and there is no sense in trying to trouble shoot when the single most important part of making your car run well has been modified by a hack who has no idea what they are doing.

If you want to classify WOT pulls as "drivability", you do you. Not the case for me.

just because it is worth reminding everyone, this "tuner" that you choose to use has stated in writing that nothing was wrong with a tune to a customer. this person was inquiring as to why he was making less power on the tune with a 3076 vs stock.

Awesome story, I am not "this person" nor do I care about how fast my car is. Again, be productive.

all that said I don't think that your issue is tune related, based on the odd pressure curve you have it looks like a leak somewhere to me.

Noted

 

[Easter Bunny]

Did you even read my post?