Misfire Under Load with no CEL

Frozen Blue · February 23, 2016, 10:46:23 AM

I need some help here. I was logging in Sport mode this morning and when the car shifted to 3rd it fell flat on its face, threw a CEL, and began shuttering. Pulled over immediately and the car had a very rough idle. I shut the car off and checked for any codes and had none. Started the car back up and it ran fine. WTF? Checked the log when I got to work and everything looks ok. Had a FRP dip but it doesn't look to bad. AFRs were in check until that happened. WGDC, OAR, everything just zeroes out.

http://datazap.me/u/jawiedemann/wtf-modified?log=0&data=4-12-14-15-17-22&zoom=220-2514

Mods are:

170° thermostat
3 bar Map sensor
Currently tuning for 91 with Torrie

And yes before people jump on me, I emailed Torrie immediately and am waiting for a reply.

SHOdded · February 23, 2016, 11:36:45 AM

As soon as I saw this, I thought 2013+? They have had problems with the FDMs, and this may have been the first warning of a future failure. Have all recalls been performed on your SHO? Check at http://owner.ford.com to be sure. Could be the controller for the fuel pump also. Should ultimately set a code though there were none at this time. Good you checked before starting it back up as some codes get erased on restart.

ZSHO · February 23, 2016, 11:58:52 AM

Did you swap the correct 3-bar sensor? Z

Frozen Blue · February 23, 2016, 12:22:50 PM

Quote from: SHOdded on February 23, 2016, 11:36:45 AM
As soon as I saw this, I thought 2013+? They have had problems with the FDMs, and this may have been the first warning of a future failure. Have all recalls been performed on your SHO? Check at http://owner.ford.com to be sure. Could be the controller for the fuel pump also. Should ultimately set a code though there were none at this time. Good you checked before starting it back up as some codes get erased on restart.

No recalls done on it from what I can see.

SHOdded · February 23, 2016, 12:29:01 PM

Check the TSBs next
http://www.ecoboostperformanceforum.com/index.php/topic,3836.0.html

See if anything jumps out at you ... Stutters can also be caused by chafing knock sensor wires (less common on 2013+) or fuel injector issues. Though I am leaning towards a fuel pump based issue here.

Frozen Blue · February 23, 2016, 12:59:34 PM

Quote from: ZSHO on February 23, 2016, 11:58:52 AM
Did you swap the correct 3-bar sensor? Z

I hope so. I swapped in the 3 bar sensor I bought from Torrie into the intake manifold.

Frozen Blue · February 23, 2016, 02:04:24 PM

Quote from: SHOdded on February 23, 2016, 12:29:01 PM
Check the TSBs next
http://www.ecoboostperformanceforum.com/index.php/topic,3836.0.html

See if anything jumps out at you ... Stutters can also be caused by chafing knock sensor wires (less common on 2013+) or fuel injector issues. Though I am leaning towards a fuel pump based issue here.

What's an FDM?

FoMoCoSHO · February 23, 2016, 02:16:27 PM

Quote from: Frozen Blue on February 23, 2016, 02:04:24 PM
Quote from: SHOdded on February 23, 2016, 12:29:01 PM
Check the TSBs next
http://www.ecoboostperformanceforum.com/index.php/topic,3836.0.html

See if anything jumps out at you ... Stutters can also be caused by chafing knock sensor wires (less common on 2013+) or fuel injector issues. Though I am leaning towards a fuel pump based issue here.

What's an FDM?

Fuel delivery module aka low pressure pump.

glock-coma · February 24, 2016, 12:42:52 PM

If it's a 13+ I would guess injector or fuel delivery module.

AJP turbo · February 24, 2016, 01:02:34 PM

Also sounds the car went into limp mode....ask torrie if he has changed the torque tables, and why.

I used to think they needed to be changed...when they do get changed the torque inverse tables need to be changed to match the torque tables ...if they dont, the torque calculations will be wrong and limp mode may result

Were you actually logging misfire counts?...the car falling on its face as you say doesnt nessasarily mean misfire

Frozen Blue · February 24, 2016, 02:48:49 PM

Quote from: ajpturbo on February 24, 2016, 01:02:34 PM
Also sounds the car went into limp mode....ask torrie if he has changed the torque tables, and why.

I used to think they needed to be changed...when they do get changed the torque inverse tables need to be changed to match the torque tables ...if they dont, the torque calculations will be wrong and limp mode may result

Were you actually logging misfire counts?...the car falling on its face as you say doesnt nessasarily mean misfire

I'm still waiting on Torrie to get back to me but thanks for the help. I'll ask him.

I wasn't logging the Misfire PID but I think I'll add it now. The car is running normally still. I'm tempted to do a compression check this weekend. When the car gets put in Limp Mode does it idle rough? And does it reset the OAR?

AJP turbo · February 24, 2016, 03:21:17 PM

I would say it could idle rough and i dont know about oar resetting but i would say maybe because i would think it reverts back to a base table rather than a scaled spark table learned from oar

Frozen Blue · February 25, 2016, 10:37:41 AM

Well it sounds like it was tune related thank God. I got an email from Torrie stating that he handled it. I don't like to think it could be injector or fuel pump related. I don't like the idea of a cylinder running lean due to an injector quitting while in boost.

And FDM, that's a new one. I've always called it "in-tank fuel pump" or "lpfp(low pressure fuel pump)". Learn something new everyday.

SHOdded · February 25, 2016, 11:09:50 AM

FDM is what Ford refers to the unit as, seeing as it can be a combination of fuel pump, filter, regulator, etc.

AJP turbo · February 25, 2016, 12:46:19 PM

I thought the fdm was the box or controller and not the pump....the late model mustangs the FPDM is the box that drives the in tank pump...i would imagine the sho has one as well