Looong crank and stalling.

[ojuniour]

I've updated post with datazap logs.

[Ultramaroon]

Gun to my head, I'd say the spill valve on your DI pump is jacked.


Or maybe a leaky direct injector. Depends on what experts say about the fuel trim. Not sure how to read -9% but it seems that means the system is trying to lean out the mixture because something else is making it rich. I remember a discussion here about how fuel trim indications respond counterintuitively in some cases.


Upshot is your DI rail never reaches target pressure and you can see the pulses corresponding to pump piston cycles.

[ojuniour]

Originally Posted by Ultramaroon

Gun to my head, I'd say the spill valve on your DI pump is jacked.


Or maybe a leaky direct injector. Depends on what experts say about the fuel trim. Not sure how to read -9% but it seems that means the system is trying to lean out the mixture because something else is making it rich. I remember a discussion here about how fuel trim indications respond counterintuitively in some cases.


Upshot is your DI rail never reaches target pressure and you can see the pulses corresponding to pump piston cycles.

I did replace the high fuel pump though...unless I got super unlucky and got a non-fully working one as the original..
regarding the negative fuel trim..I do believe i have a valve leak somewhere as i get misfires on cold start and slightly tapping on gas. In this case, could it be an eletric issue going to the valve itself then?

[ojuniour]

beside won't a leaky DI be more audible..I mean when you are more fuel..in the cylinder you'll probably get quite a few popping noises, misfires,..and unusual smokes from the exhaust?
I didn't get all that. I also had to be a huge leak for such sudden pressure drop too. Please do correct me if I'm way over my head on my logic.

[Ultramaroon]

Burned, leaking DI injector seal causes the popping sound. That's not the same as an actual leaking injector. Figure out why DI fuel rail never reaches target pressure. That's it.

[Irace86.2.0]

Originally Posted by Ultramaroon

Gun to my head, I'd say the spill valve on your DI pump is jacked.


Or maybe a leaky direct injector. Depends on what experts say about the fuel trim. Not sure how to read -9% but it seems that means the system is trying to lean out the mixture because something else is making it rich. I remember a discussion here about how fuel trim indications respond counterintuitively in some cases.


Upshot is your DI rail never reaches target pressure and you can see the pulses corresponding to pump piston cycles.

I thought the same, but when I looked at my old logs, I was 2-3 mpa at idle and not at 4/target, and I didn't really have an issue of stalling. I also don't have pump cycles. The pump is driven off the cam lobe, so the pump cycles would be perfectly timed spikes, but they aren't. Even if the purge/slip solenoid opened, there would still be something, but mine shows no such movement or variance, whether using direct injectors or not. Even if you zoom in to change the scaling, it doesn't look anything like his (see more below).

I think the high pressure fuel pump is clearly dropping pressure before the engine dies, so it is likely the car stalls when it runs out of fuel. My fuel maps ran on port injectors only. I can't tell if his are running on port or direct or both at idle because he didn't log "injection time direct final ms" or something that would indicate the duty cycle or something.

His fuel tank fuel pump duty cycle is flat until rpms drop and then it rises to 80-90%. Does it rise because fuel pressure is dropping on the high pressure fuel rail, so it is trying to compensate by increasing duty cycle?

https://datazap.me/u/ojuniour/11-42s...-36&solo=34-36

The odd thing is the injectors seem to be jumping back and forth on this log from 100% pi to 50% and then as fuel pressure drops there is a flip from 100% and 0% more often. The other log it is flipping the whole time.

https://datazap.me/u/ojuniour/11-43s...-32-36&solo=36
https://datazap.me/u/ojuniour/11-42s...-32-36&solo=36

I think the thing to do is put a fuel pressure gauge on the low pressure side and determine if there is enough fuel pressure feeding the engine and high pressure fuel rail. Seems like there would be CEL for a drop in fuel pressure, but there wasn't. I would bench test the solenoid on the HPFP to make sure it clicks open and close, and if not, perhaps that is the problem of why the pressure is dropping.


Compare to my idle (see below), which is idling with a few throttle blips. I don't know if his tune is different where my tune is meant to run ports at idle, direct at low duty and both at high duty, and his is suppose to run both all the time, but can't or what. His AFR seems to fluctuate higher and lower than mine at idle too. My high pressure fuel rail pressure is flat or basically a smooth straight line that gradually decreases when the spill valve likely opens, but his is wildly oscillating up and down, which means his direct injectors are drawing from the rail or his fuel pressure isn't being maintained well like it is getting an intermittent signal from the spill solenoid. What else could it be?

https://datazap.me/u/jirace/test-com...-36-37&solo=37

[Irace86.2.0]

On this log of his that he sent me, there are a few times when direct and port injector time is zero, which seems odd.

https://datazap.me/u/ojuniour/more-m...zoom=1132-1702
https://datazap.me/u/ojuniour/more-m...zoom=1132-1702

From here it seems that the fuel pressure rail is not fluctuating when the direct injector time is zero, yet it still seems a little all over the place like it should be smoother.

https://datazap.me/u/ojuniour/more-m...zoom=1132-1702

[FR-S2GT86]

@ojuniour

I have a couple of questions:

1) When you are replacing parts, are you using genuine OEM parts from a dealer or are you sourcing them from Amazon or eBay or some other online store? I ask this because the existance of counterfeit parts are at an all time high right now.

2) Have you checked your bypass valve operation? Before installing my Harrop, I had to work the bellows in and out several times as it was sticking. And this was a brand new unit directly from the factory.

3) Have you tried reflashing your ECU with the most current revision from your tuner?

4) Who is your tuner?

[Ultramaroon]

Originally Posted by Irace86.2.0

What else could it be?

Good stuff! I compared against logs of my stock tune and known parameters logged using tactrix. I need to spend quality time reviewing your logs. At work now and have an evening project. I'll update this post at earliest tomorrow evening. Maybe one of our real experts will drop by in the meantime. Fingers crossed.

[Irace86.2.0]

Originally Posted by FR-S2GT86

@ojuniour

I have a couple of questions:

1) When you are replacing parts, are you using genuine OEM parts from a dealer or are you sourcing them from Amazon or eBay or some other online store? I ask this because the existance of counterfeit parts are at an all time high right now.

2) Have you checked your bypass valve operation? Before installing my Harrop, I had to work the bellows in and out several times as it was sticking. And this was a brand new unit directly from the factory.

3) Have you tried reflashing your ECU with the most current revision from your tuner?

4) Who is your tuner?

The HPFP is like $500+, and I think he said here that he sourced a "good" used one on eBay, so it is possible both are bad.

I sold him my SC, so it has plenty of life on it and didn't have problems when I had it. If the bypass was staying open then that would be fine at idle because it is suppose to be open. If it was open when on throttle then he wouldn't build boost, and that is not the problem. If it stayed closed or was sticking at idle then it would be trying to build a little boost, so that could throw things off, but I don't think it would cause a stall or change in fuel pressure. All his stall logs don't contain manifold pressure readings, so I don't know that, but I looked at his misfire log that didn't include a stall that I posted above, and he is pulled 22+ inHg of vacuum off throttle in those situations, so I don't think the bypass is sticking closed.

This jumpy idle has the fuel pressure on the rail become erratic once the direct injectors come online, but the system switches once from port to direct, and it doesn't flip back and forth like in his stall logs, which is odd.

https://datazap.me/u/ojuniour/startu...-32-38&solo=20

Wouldn't it be funny if all of what was causing the fluctuations was a loose grounding bolt on the direct injection ECU (EDU)?

[alphasaur]

Looking at your first log I had the same issue with fuel system status constantly oscillating between 2-4 and it would produce and audible click, I threw parts at it too and it ended up being the tune. Not sure if it was a glitch with ecutek or what, but a different tuner sent me a basemap and it was all sorted. Can you PM me who is tuning you?

[ojuniour]

Originally Posted by FR-S2GT86

@ojuniour

I have a couple of questions:

1) When you are replacing parts, are you using genuine OEM parts from a dealer or are you sourcing them from Amazon or eBay or some other online store? I ask this because the existance of counterfeit parts are at an all time high right now.


2) Have you checked your bypass valve operation? Before installing my Harrop, I had to work the bellows in and out several times as it was sticking. And this was a brand new unit directly from the factory.

3) Have you tried reflashing your ECU with the most current revision from your tuner?

4) Who is your tuner?

Currently right now.. all OEMs! except from the used HPFP which is still sourced from a relatively low mileage donor.. though the issue didn't change.so That's pretty much crossed out.
Yes. Bypass seems fine. This is a recent issue. I've had the harrop installed for few years now - never this particular issue.
I've reflashed different tune from my tuner..going all the way to the base one ..It didn't matter.
Tuner is Mike from Xer-Limit.
i'm going to be doing a fuel pressure test (among other stuff later today).. I have a feeling there is a leak between the low fuel pump to the fuel rail, and the issue exacerbates as temp rises which means leaky line soften my high temp? Oh god that sounds really terrible.
I do kinda smell fuel though (which i completely forgot to mention)

Thak everyone for the continued great input. I will log alot more data today.. idling and cruising.

[Ultramaroon]

These tunes operate nothing like the stock mode. Idling at temp, stock logic engages full DI. My rail pressure tracks steadily with target.

[Irace86.2.0]

I'll let @ojuniour update you guys on the specifics, but we may have found a fuel leak on the low pressure side at the pump. He should know by the end of the week.