Car Stalls at Idle

[ojuniour]

one of two things most definitely: Heat soak or fuel system.

You need a live full log. upload to datazap.

[ojuniour]

Originally Posted by Stevedave

Thanks. Here's a link for a data log.



https://datazap.me/u/stevedave/frs-1...g?log=0&data=8

Not quite enough info with that log?

what are you using to log?
Log as many parameters as possible
Anyway I had something similar not too long ago..
Was driving me crazy..
Long story short, it was the Fuel Pump (or could be the regulator) for me.
i was kinda having the issue prior to me replacing the fuel pump..but it gets worse after replacing it..but apparently i didn't install it properly.
I just replaced the whole fuel pump assembly with a new pump. I took the opportunity to upgrade the pump.

Car will start fine and then stall after a while out of no where , it starts right back up ..
But then gradually get worse in which i have to wait like 5 to 20 minutes before it starts again.
The longer it goes the shorter it stays on and the longer the cranking.

You can easily test the fuel pressure by getting a fuel pressure/vacuum tester, unplug one of the Low pressure fuel line (preferrable the one closer to oil filter, plug in to the fuel pressure test.. Put the car into ON position without starting the car. You should see the pressure build up and stay at least or above 35 to 40 psi ( i think can't remember).

keep it that way for like 5 minutes or so to make sure the pressure isn't dropping..

My thread:
https://www.ft86club.com/forums/showthread.php?t=154165

[ojuniour]

Originally Posted by Stevedave

Using OBDLinkMX+ and the app specifically for it. There are probably around 100 SAE PIDS to choose from. I selected 26 in the log I posted, but I guess not all apply to my car or theyÂ’re limited to some makes and models?

Suggestions from you or anyone on which SAE PIDS to select? Screenshots of selected PIDS while in the app might be easiest to show?

I went through your thread. My car has never experienced any difficulties starting back up after stalling. When I stored it for 6 months, I did remove the battery. I had it tested before re-installing. I was instructed to re-install the battery, start it up and let it idle for 30 mins then drive it home. I let it idle for about 25 mins, backed the car out of the unit, got out to close the unitÂ’s door and it stalled. It started right back up, but stalled several times on the drive home. It would start back up and I was able to keep it from stalling by pressing the accelerator and keeping it around 1,200 - 1,500 rpms.

When I recently did the idle re-learn procedure, I could hear the throttle body adjusting/moving or whatever and it hasnÂ’t stalled since. Perhaps I should clean the throttle body and do the idle re-learn again?

The car is stock other than an Invidia Gemini R400 Dual Tip Catback Exhaust, a hard wired radar detector and a starlight headliner - all installed by previous owner. I never use the headliner. IÂ’ve noticed while driving at night, sometimes the headliner will light up for a split second. Almost like thereÂ’s a power surge? Seem to notice it on hard acceleration.

I would like to do some more data logging regardless.

Even without cranking issue, it could still be a fuel pump issue but now that I think about it, it could also be related to a failing alternator.
I have ecutek so I can't really thoroughly help you with the PID.
Are you tuned?

[ojuniour]

Originally Posted by Stevedave

The vehicle is not tuned. I’ll have the alternator tested at one of the parts stores in the next couple days.

You should also try to log the battery voltage... That should be a relatively quick way to deduce if it's an alternator/battery issue ..

[ojuniour]

Update?

[ojuniour]

Originally Posted by Stevedave

New data logs

https://datazap.me/u/stevedave/frs-2?log=0&data=5

https://datazap.me/u/stevedave/frs-3?log=0&data=5

https://datazap.me/u/stevedave/frs-4?log=0&data=5


8/08 - I cleaned the throttle body (it wasn’t very dirty) and did the idle re-learn and all was good until recently. Went for a spin last night. Car randomly fumbles at idle, almost stalling.

Scanned for codes as well

There are still not enough log parameters to fully determine/pinpoint a causation.
The Injection Mode (fuel system) is pretty interesting though.

Fuel System 1 (After Staring engine) = Port Injection ON , Direction Injection OFF
Fuel system 2 (between 3k and 5k rpm in closed loop - meaning after fully warmed up) = Port Injection is OFF, Direct Injection is ON
Fuel System 3 (usually below 3k rpm) = Both Port and Direct Injection ON
Fuel System 4 = Both Port and Direct Injection OFF

Reference image attached

For status 4 , it means both the Port and Direct injectors are not inactive - or rather not providing fuel...where it's showing up in the logs (which I'm assuming in that moment you will experience stumbling..jerkiness, or stalling as the RPM dips. ( I mean duhh..no fuel is being delivered to the cylinder from ANY of the ports - just look at the logs you will notice it lines up with the rpm dip when you have fuel system 4.
Oh and this also causes the 'fuel rail pressure psi' dropping for that obvious reason..I mean no fuel no pressure.

I would definitely start looking into the fuel pump /assembly.

It's not that difficult to replace and go for cheap preowned on ebay for about $70 USD.

Just based on the limited date presented, it definitely point to something in the fuel delivery system...
So start tracing wires and hoses in that area.

Excuse the typos...