Looong crank and stalling.
 

Long story short i've been having misfires for a while now and i even posted a thread about it: https://www.ft86club.com/forums/showthread.php?t=153985

But lately things have gotten worse.
For the past few months, I've been progressively getting a long crank. it has gotten worse overtime.
The first time it finally starts, I can only drive for like an hour or so and as soon as I slow down (in traffic or traffic light), the engine just stalls - lights on and all (so not a battery issue). I had to start it again - at this point I didn’t experience the [super] long start.
Well now, it got worse over time.. when it stalls now, it takes about few cranks
to get rolling again.
And the kicker now is the amount of time it takes for it to stall reduces overtime. Basically like maybe about half an hour [that I drive around or even sitting at idle], it just stalls - fuel cut of some sort, and after consecutive next successful startup the length of the engine running reduces all the way down to like a few minutes. And I have to wait like 10 to 15 minutes to get it started again - going through multiple long crank.
Only thing that came through my mind is maybe the coolant temp sensor is the cause? But the techstream/ecutek seems to be reading things right - but I still have a feeling there might be something that’s overheating…no idea.
I have changed the sparks, coils, crank position sensor, camshaft sensor, tested battery (good). THe coolant temp seems fine (so I kinda ruled out the temp sensor) 0- All these being monitored on the ecuTek app.
Last result is to use techstream to see if I get get any useful freeze data during the stalling below:
[See Attached pictures]

I would really appreciate if anyone can sorta point me in the right direct looking at the freeze data. Only thing i am sorta aware of is the fuel pressure not matching the target. :iono:

Edit:
here are datalog of the stallings:
https://datazap.me/u/ojuniour/11-43s...g=0&data=27-36
https://datazap.me/u/ojuniour/11-43s...g=1&data=27-36
https://datazap.me/u/ojuniour/11-42stall?log=1&data=27
https://datazap.me/u/ojuniour/11-42stall?log=2&data=27
https://datazap.me/u/ojuniour/11-43s...g=0&data=27-36
https://datazap.me/u/ojuniour/11-43s...3-36&hg=22-3-4

let me know if there are other parameters you may want to include in the future for further diagnose..
The only thing that I know (according to my limited knowledge) would be the fuel rail pressure droppping way lower before it stalls.
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UPDATE:

Well upon close inspection, it was the fuel pump not properly installed. it was missing additional o-ring and the fuel pump container wasn't snapped down properly into the fuel cannister (only one out of three was snapped in place). That's the issue for the fuel starvation.
Now mind you i was already having this issue prior to the new pump...but since then I have replaced the crankshaft position sensor (tested it and no ohms and the magnetic force was weak compared to the new replacement), one of the camshaft sensor that was leaking oil, and high pressure fuel pump. So Anyone one of those could have fixed the original issue after the [low pressure] fuel installation.

The next stage now is the figure out why I'm still getting those misfires on cold start and when tapped on the gas for split second. I'll post the logs for those later.

Here is the current logs i took today after the fuel pump fix (so sign of vacuum leak or something else):
fuel trim acts according to rpm /acceleration angle:
Cruising logs:
https://datazap.me/u/ojuniour/cruisi...ta=40-52-57-60
https://datazap.me/u/ojuniour/cruisi...ta=40-52-57-60
https://datazap.me/u/ojuniour/cruisi...ta=40-52-57-60
as you can se the massive positive fuel trim.

Idle logs:
https://datazap.me/u/ojuniour/idling...ta=40-52-57-60

so far the target fuel pressure target seems to now be on point with the current pressure.

oh and you disregard the p0420...I'm running catless and I don't want that tuned out yet.

Oh and I also though it was the fuel pump. I've since completely changed BOTH the high fuel pump and low fuel pump .
Yes, I know..I've been throwing stuff hoping something sticks. I just don't want to waste more time and money trying to decide things all on my own. :(

What does compression test say?

I've yet to do compression test.
I believe I can simulate a [compression] active test in Techstream for all cylinders. I'll give that a shot.

Now at this point, I'm not if that would yield any accurate result due to the cranking issue.

It can only be one of two things, intermittent/no spark or no fuel. If it was a carbureted engine I'd say you had a stuck/sticking float that starved the engine of fuel. You have to wait for the float bowl to file up to go again.
I had a number of problems on my MV Agusta that caused the engine to stall and then not restart for years. Error from ECU caused the TPS to read idle was 0 rpms. Then there was an air leak in the number one inlet tube, the only cylinder to have an air sensor and faulty fuel maps. Almost killed me. Not to mention the starter sprag issues. MV Agusta America wrote a special map just for my bike along with some trick parts and fixes. Took five years and they still hadn't addressed the starter sprag issue. After ten years (the last three I didn't ride it) I sold it so cheap I literally gave the bike away.

yea..no doubt it's a fuel/spark related. and it's highly unlikely it's a compression issue because of the symptoms - Maybe the cranking, but not the wild stalling.
I'll still do the compression test just to be sure.

The FA20 does crank using the port injection 100%, correct?

Techstream compression test just turns the crank for you. You still need to measure it with a pressure gauge

I know the relative compression test isn't 100% accurate..but it helps as a starting to figure out how bad it is..
I will still do the absolute test anyway. Taking out the spark is just a PITA- :iono:

I'm by no means an expert, but am I correct in reading that your MAF shows higher air mass as the rpms go down?

Once upon a time I had weird symptoms and similar codes from a vacuum leak.

Yep...and other parameters like the fuel pump duty.. not sure if that's by design..

I'm your case where exactly did you detect the leak?
Maybe that can be helpful.. Thanks.

Mine was easy. I had just installed an oil catch can. One of the hoses that I was sure was tight. I made a diy smoke machine to find it.

I do have a smoke machine which I used months ago for the misfires...but haven't since this current symptoms.
I'll try running the test again.
Thanks for the input.

I've updated post with datazap logs.

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?

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.

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.

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

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

@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?

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.

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)?

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?

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.

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

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.

I'll deal with that later with my tuner.
Now regarding the stalling and long crank. Think we may have found the issue.
The fuel pump replacement on the AEM pump is missing additional o-ring?
I had the engine idle for few minutes. turned it off and removed the fuel line for compression test.
Guess what?
No fuel? like just a couple of drops.. I mean i literally just turned it off and the car should hold pressure.
So I went straight the fuel tank and did the compression there to make sure the fuel line isn't leaking along the way (from the pump).
I got same result (pressure is only up to like 30psi and then drops right back to 0). I finally discovered that the pump is missing missing o-ring which is (probably causing the long crank as far as I know). Now, I won't jump into full conclusion if that's what's causing the stalling after reaching driving temp but I'm betting it's might be.
We shall see once i reassembly things ~ waiting on the fuel kit.
:23:

Oooo... Yes. Very interesting. ...and plausible!

Alright lads and gents. I've updated the original Post for the update.

Thanks for the continued input. Hopefully this helps someone else in the future 😤

whatever you guys think of the current logs?

For the idle log:

https://datazap.me/u/ojuniour/idling...88-93&mark=961

I highlighted every perimeter that seems to be cycling with the idle.

--Your fuel rail pressure is hitting the 4 mpa target.
--No misfires
--Fuel trims seem to be within acceptable levels, but I am not a tuner, so take that with a grain of salt. I see people saying within 10% as normal. The LTFT is negative, but this could be because of the repeated oscillations in fuel delivery making things rich, so the system is trying to reduce fuel. The STFT should oscillate back and forth to make fine adjustments and to keep the catalytic converter happy at idle.
--Idle is oscillating, but I don't know if it is really noticeable oscillating between 800-850 rpms. Seems like the spark, injector, target map, are all adjusting, and we see maf increase, map increase, and fuel increase to meet the adjustments. The idle speed control (ISC) system per ECUTEK (I believe that is what ISC acronym is referring to) is confusing me. I don't really know what it is because the DBW system would control the throttle, but the throttle is staying "closed" or isn't fluctuating, so our cars do not have the typical air control valve or something to bypass the throttle, unless I am wrong; the system seems to be making corrections or responding cyclically inline with the other parameters.

https://datazap.me/u/ojuniour/idling...56-80-82-88-93

--I'm confused why your target is oscillating with your actual AFR. My target is locked at 14.7 at idle, and my actual is slowly moving up and down within 0.05-0.10, but you are hitting 0.5 and are oscillating oddly. What is changing the target AFR or why isn't it locked at 14.7 at idle? I don't know.

https://datazap.me/u/ojuniour/idling...8-93&mark=1449

--The oxygen sensor seems to be fluctuating, but I don't know if this is normal with a changing idle, or if the oxygen sensor is sensing a leak, which is causing the idle fluctuations. Chicken or the egg scenario.


For the other logs:

--Fuel rail pressure is matching target now.
--No misfires.
--Long term fuel trim is much too high. System is lean and trying to add fuel. This suggests a vacuum leak to me or exhaust leak near the O2 sensor. Maybe something between your MAF and TB. Do that smoke test and exhaust manifold test like I mentioned on texts.