PDA

View Full Version : 2002 F-Body missfire during AutoVe



GAMEOVER
May 30th, 2010, 03:42 AM
Was doing the AutoVE on a 2002 5.7 6 Speed, everything was going perfect and all of a sudden it went Extremely Rich. Pulled over, shut the motor off, did a free-air calibration on wideband(Innovative LM-2) turned the motor back on and motor has a real bad missfire, motor shake's, stumble's between shift's.....Wideband is showing rich AFR(12-13.2)....Before incident AFR was 14.5 in all part throttle areas, under 4000RPM, & Ben's were .99-1.01 .......I'm going to do a compression test today but hopefully it's something minor..... Any ideas on what might have happened?
Stuck open injector?
Bad coil?
Everything was going perfect...:shock:

joecar
May 30th, 2010, 08:06 AM
If coil is bad, then unburnt fuel/oxygen would pass thru, wideband would see excess oxygen (lean).

If injector leaks then wideband would show rich like you indicated.

joecar
May 30th, 2010, 08:08 AM
Is it valid to perform free air cal when gases may still be present in exhaust...?

Don't you have to get out residual gases first...?

:)

GAMEOVER
May 30th, 2010, 10:20 AM
I actually unbolted wideband from vehicle and performed free-air cal, (small portable jack...:shock:)

GAMEOVER
May 30th, 2010, 10:34 AM
Performed compression test and #1 cylinder showed 1psi, cylinder's 2-8 showed 140psi average....
Removed valve cover & on cylinder #1- Comp Cams roller rockers were just laying on top of head...:Eyecrazy:
Chromoly pushrods were OK, but aluminum Rocker mount was broken at base of rocker. It split like a popsicle stick.....

joecar
May 30th, 2010, 03:20 PM
Ouch, rocker mount just broke... :shock:

Insufficient air, injector fires, plug fires resulting in rich combustion...

Pics...? :)

joecar
May 30th, 2010, 03:21 PM
Ah, I knew you would have performed free air cal in free air...:cheers:

GAMEOVER
May 30th, 2010, 05:39 PM
I took a pic with cell-phone kinda bad quality...:D

5.7ute
May 30th, 2010, 06:18 PM
Yikes. Hitting those 8000 rpm cells has a tendency to do that. (joke)
I had an exhaust roller rocker let go on mine as I was on the way to pick my daughter up. I was glad it happened then & not a few hours earlier when it was being pushed to 7000RPM on the dyno. (I wont mention the brand as they went out of their way to rectify the situation)

joecar
May 30th, 2010, 08:15 PM
Why did the rocker mount break...? I have one in my hand here and it does look very light.

GAMEOVER
May 31st, 2010, 02:23 AM
The mounts look & feel like cheap pot metal aluminum...
2 reason's, might be the double valve-springs or the 1.85 roller rockers...:D