Ford Crown Victoria misses, hesisitates, stumbles, AFTER warmup (1989, 302)
L. Mark Bruffey
My Crown Vic runs rough and misses on light acceleration, especially
at slow speeds AFTER warmup. I do not have a temp guage, but I can
tell it starts exactly the same time in daily commute to work, for
example.
Car has 152k miles, 302, SEFI. Relatively new spark plugs and wires (8
months or so, maybe more)
Symptoms:
AFTER WARMUP
misses on light accel from stop, but goes great if you stomp on it
idles rough for a bit after warm restart
feels like timing is being "thrown around"
miss can be felt at cruise speeds, but acceleration is still good
even runs without missing warm, sometimes, or for a while, like it's
"in the groove"
#5 cylinder fouls, but compression tests good 165/185 dry/wet
runs very smooth cold (minnesota cold)
starts right away cold
Diagnostics:
No codes, but I recently replaced the EVP sensor which was bad (codes)
in hopes of alleviating these symptoms.
Cannot hear or find any vacuum leaks.
Checked wire routing carefully for the old 7/8 crossover problem.
Actions:
I have an identical engine in a 1989 Colony Park Wagon that runs
PERFECTLY (smoothest 302 I ever had)
swapped entire distributor and tfi module assembly
swapped primary coil
swapped egr valve
swapped throttle position sensor
replaced #5 plug twice
replaced #5 spark plug wire
installed new oxy sensors
Next on the list:
MAP Sensor?
MAF Sensors?
Temp Sending Unit?
Knock Sensor?
Injector? If injector bad, I would expect constant miss, not after
warmup.
Any and all help appreciated!!
Thanks,
Mark
Crown Vic Victoria engine misses missing hesitates hesitation idles
rough idling
Jim Nagy
Bruffey <mbru...@centralseminary.edu> wrote:
> Hi!
>
> My Crown Vic runs rough and misses on light acceleration, especially
> at slow speeds AFTER warmup. I do not have a temp guage, but I can
> Next on the list:
>
> MAP Sensor?
> MAF Sensors?
> Temp Sending Unit?
> Knock Sensor?
> Injector? If injector bad, I would expect constant miss, not after
> warmup.
>
> Any and all help appreciated!!
>
I had an '89 Crown Vic that drove me crazy with a miss, until I changed
a 'radio interference capacitor' at one of the coils. I think it was
faulty, and allowed noise to get into the module, throwing the timing
way off. Clip another across, and see if that makes a difference.
--
Jim Nagy
Elm Electronics
L. Mark Bruffey
You know, my dad told me once that the very same thing happened to him
years and years ago. Maybe you're right!
Could you hear that bleed off on your AM radio?
I wonder if I could do the test by simply removing that condensor
completely?
OTOH,
Now that the EGR valve has been in my other car a couple days, that
car is misbehaving, so I think that is part of the problem. Maybe I
need to recheck plugs again after having installed the ego sensors and
swapping the egr valve. COuld have fouled up again before I made the
swap. Hmmmmm.
Thanks,
Mark
Jim Nagy
Bruffey <mbru...@centralseminary.edu> wrote:
> > >
> > > My Crown Vic runs rough and misses on light acceleration, especially
> > > at slow speeds AFTER warmup. I do not have a temp guage, but I can
> > > Next on the list:
> >
> > >
> >
> > I had an '89 Crown Vic that drove me crazy with a miss, until I changed
> > a 'radio interference capacitor' at one of the coils. I think it was
> > faulty, and allowed noise to get into the module, throwing the timing
> > way off. Clip another across, and see if that makes a difference.
>
>
> You know, my dad told me once that the very same thing happened to him
> years and years ago. Maybe you're right!
>
> Could you hear that bleed off on your AM radio?
>
No, not that I remember, but I normally only listen to FM. My wife had
a '90 Topaz, and I went through changing MAPs, etc. between the two,
and hit on this somehow. If you don't have a spare from an old tuneup
kit, why not just clean up the connections to it (crack the coil bolts
and retighten too so that you revive the ground side). If this changes
your problem at all, then you are close to the source...