Misfire diagnosis needed....99 Crown vic

[rusty ol ranger]

Thought i had it licked...im starting another thread because the other one derailed...and i got better info now.

Symptoms...

Cuts out around 30-35 under heavy throttle...sometimes will totally lose power....normally wouldnt stall but it did today. Shut it off, it fires right back up, and generally wont do it again untill it sits for a while. Im also getting the red battery light...totally randomly. Sometimes its on for a second...sometimes for a minute...volt gauge never moves and electrical power seems to stay. It is also now...sometimes...missing after you come to a stop. Sometimes after 10min of idleing, sometimes right away, lights also weirdly pulse during this...and its a crap shoot if the battery light lights up during....again...shutting it off and restarting makes it all go away. About 50% of the time it will act like it wants to stall going into gear...it dont...but it bogs out and then kinda chugs back to life. I also for the first time tonight felt what im pretty sure was torque converter shutter.

Codes im getting are for "primary control circuit open/short"...for cylinders 4/5/6/8. One cylinder (4) on pass side bank, 3 on the drivers. For some reason cylinder 7 seems immune...despite its bank mates going crazy.

Also...here are some missfire counters that i have no idea about...

According to the google one of those usually indicates a random/mutiple missfire the computer cannot pinpoint...

So why am i getting specfic codes?
Why does shutting off the key and then right away firing it back up clear everything up?

Why does it only happen early on in drive cycle and under hard acceleration or at idle?

This almost has to be the PCM at this point dont it? Along with the shudder i couldnt recreate and a trans that acts perfectly normal otherwise?

Can some of the heavy hitters chime in here? Im literally pulling my hair out.

Should add...All 8 plugs/coils are new (motorcraft), cam sensor/pigtail are new, intake manifold is new, MAF is new, alternator is new, starter is new, battery is basically new, cats are new, fuel pump is new..ive checked every ground on the thing and they look new (its only been in the salty north a couple years)

 

[bobbywalter]

flood car?

 

[bobbywalter]

sure as fawk sounds like it to me.

 

[bobbywalter]

the converter clutch bumping could be the stall. there is a myriad of reasons that can happen and not report.


this should have a mechanical throttle body.

so the heavy load should be recordable. what is that you posted pictures of? can it record the drive cycle and see what it is doing like hp tuners?

 

[85_Ranger4x4]

the converter clutch bumping could be the stall. there is a myriad of reasons that can happen and not report.


this should have a mechanical throttle body.

so the heavy load should be recordable. what is that you posted pictures of? can it record the drive cycle and see what it is doing like hp tuners?

Mode 6 is a Forscan thing

 

[bobbywalter]

Mode 6 is a Forscan thing

mine dont look like that....

 

[bobbywalter]

there is a power issue clearly.

whether its corrosion in the pdb or just a bad main connection down fuse of the battery is hard to say.

i actually suspect several power issues.

didnt you already swap ecms? the damage you have found already i would look careful at the fuse boxes.

generally there would be other anomoly happening with radio and windows lights ect if its a flood rig. you dont seem to have too many issues that way. does it have a police package wiring setup in the pdb? maybe a main power connector is loose from equipment removal and arcing out...

 

[85_Ranger4x4]

mine dont look like that....

Mine doesn't either but who knows what kind of Tandy laptop Rusty has...

 

[rusty ol ranger]

flood car?

No not a flood car.

the converter clutch bumping could be the stall. there is a myriad of reasons that can happen and not report.


this should have a mechanical throttle body.

so the heavy load should be recordable. what is that you posted pictures of? can it record the drive cycle and see what it is doing like hp tuners?

I dont think so. Its a maddox md14 scanner from harbor freight. The reason i was wondering about the shudder is it would go away as soon as you hit the OD off button. Thats why i figured it was trans and not motor.

there is a power issue clearly.

whether its corrosion in the pdb or just a bad main connection down fuse of the battery is hard to say.

i actually suspect several power issues.

didnt you already swap ecms? the damage you have found already i would look careful at the fuse boxes.

generally there would be other anomoly happening with radio and windows lights ect if its a flood rig. you dont seem to have too many issues that way. does it have a police package wiring setup in the pdb? maybe a main power connector is loose from equipment removal and arcing out...

Not a police car. I have not changed PCM. I do have some weird lighting issues but other electrical seems fine, but like i said i cant find any rust or a waterline inside or anything along those lines. Carfax doesnt say anything about a flood. It was a salvage title...but it was in an accident when it was like one year old.

The fuse boxes also look clean and very normal. As do the two big main connections under the brake booster. Wiring harnesses also look unmolested.

One thing i forgot to add in original post...when i checked voltage with DVOM it it was showng 14-14.2, but once every 30secs to a minute...itll drop off to high single digits for a split second then come back. No idea on that one

 

[rusty ol ranger]

Ok....

Its gotta be a power issue. I just drove it to work. About 15mi. Totally normal until i got about a mile away. Started slowing down for a stop sign...i had blower on full blast and high beams. Volt light started blinking, this time the volt gauge dropped, blower slowed, lights dimmed...car was still running fine.

Took off from stop (normally), battery light still flashing but everything else returned to normal. Engine lost power, flatlined, and was missing when i pulled over. Shut it off, started right back up, and everything was fine.

 

[bobbywalter]

bring it down to champaign illinios

 

[rusty ol ranger]

bring it down to champaign illinios

I would if i had time to do it. Work is nuts right now.

I really am wondering about the PCM. I went out today...it started randomly missing while i was digging out my DVOM. No charge light this time. I checked charge it was 14.2. I wiggled and prodded every wire i could get too. Wiggled fuses and relays around .No change. I pulled a big vacuum line off the intake tube and got it to stall. Went back in the car, left key on and just turned it forward to restart.

It started but was still missing and bogging on rev. So i shut the key off and then fired it up...and guess what? Like nothing even happend.

I swapped the PCM relay and the AC cutoff relay. No go. Checked the fuseable links running to the junction box...nothing. PCM diode is intact and corrosion free like everything else ive checked. Alternator plugs are good and recieving power.

What i thought was the torque converter yesterday must have been a hard miss. It did it again today at speeds way to low for the clutch to be trying to engage (15-20mph).

After this morning i have not seen the charge light, i took a video of my DVOM to show you what the meter does but its not uploaded yet.

The only thing i havent checked yet is the crank sensor...only because i gotta pull the AC compressor to get it and i havent had that much time yet.

 

[rusty ol ranger]

This was when it was running normally...and its not the meter i tried it on my truck

 

[bobbywalter]

the front power isnt the issue.

its downstream. loose ignition switch....branch corrosion.

its a salvage car....does not mean it is not a flood car. just not reported.

the wires you had to fix so far that were bare points at the potentials.

what you are describing as a miss can be a central branch ground or power issue.

the torque converter engagement at the WRONG time is the problem....if it gets engaged at idle its obviously going to move the car or stall or bog or shudder and seem like it is missing.

pull the plug and see if it is flooded....oil not horrible but water is a potential problem...if there is a pinch or other flaw. check harness for more bare wire....grounding is how the solonoids are activated...

if there is bare wire some where and its randomly engaging with bumps...turning... braking..... engine torque movement under load ect...gonna get weird shit.


not all 4r70 will engage tq converter in 1st...if yours is that type then at least it wont stall lock......some we have to plug a hole or get a different plate....usually its a j mod and zip kit when setting these up for off road.

manually engaging the converter with a momentary bump switch is awesome crawling... providing you are geared for it..

or.

you have a mechanical issue in the DAMB buckets maybe

 

[rusty ol ranger]

the front power isnt the issue.

its downstream. loose ignition switch....branch corrosion.

its a salvage car....does not mean it is not a flood car. just not reported.

the wires you had to fix so far that were bare points at the potentials.

what you are describing as a miss can be a central branch ground or power issue.

the torque converter engagement at the WRONG time is the problem....if it gets engaged at idle its obviously going to move the car or stall or bog or shudder and seem like it is missing.

pull the plug and see if it is flooded....oil not horrible but water is a potential problem...if there is a pinch or other flaw. check harness for more bare wire....grounding is how the solonoids are activated...

if there is bare wire some where and its randomly engaging with bumps...turning... braking..... engine torque movement under load ect...gonna get weird shit.


not all 4r70 will engage tq converter in 1st...if yours is that type then at least it wont stall lock......some we have to plug a hole or get a different plate....usually its a j mod and zip kit when setting these up for off road.

manually engaging the converter with a momentary bump switch is awesome crawling... providing you are geared for it..

or.

you have a mechanical issue in the DAMB buckets maybe

The ignition switch thing is interesting....seeing as how someone has been into the column...im assuming by the fact the plastic surround is fucked up.

Which plug you talking about? The rubber one on bottom of bellhousing? Had that one out. If it was flooded it wasnt recent...its been in ohio since 2022.

All of these particular issues started after the starter shorted out. Before that the only issue was bogging down in cold weather..

Can the clutch engage in park? Cause it will miss/tremor in park as well.

Ill piss with it a bit more tomorrow or wed. The column thing i didnt think about....but im curious now because i noticed once all this started the seatbelt light stays on for way longer then it should....which probably has to do with ignition switch power up issues?

The oniy electrical issues besides this are the lowbeams doing weird shit....they dont come on and the circuit breaker trips....but it was that way when i bought it and i blamed it on the cheap LEDs. The dash clock also goes dark when you turn the lights on. Besides that all other power accessories work (windows, locks, mirrors, seat, etc).

Ill do some more digging.