crank relearn ? / bad coil drivers ?
Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
Likes: 0
crank relearn ? / bad coil drivers ? my car is getting fuel,{(35-40 psi)"thinking bad in tank regulator"} and it is getting trigger signal to the coils, but not all the coils are firing, ive tried switching around coils {left bank bracket to right bank} same coils spark 5,7,4,8 are getting good spark 6,3 are getting low spark , 2 is barley even sparking, and 1 is not sparking at all
the car trys to crank up run at a rough idle for about 2-6 seconds then bogs and dies
will a crank relearn fix this, and how do i trigger a crank relearn
if my coil drivers are bad will that cause this problem ?
the car trys to crank up run at a rough idle for about 2-6 seconds then bogs and dies
will a crank relearn fix this, and how do i trigger a crank relearn
if my coil drivers are bad will that cause this problem ?
Last edited by devic; Jul 19, 2012 at 06:52 AM.
Crank learn is not going to keep the car from running or make it run.
It's just a fine tuning for misfire detection and might make things a
little smoother, but it has nothing to do with a few-cylinder spark
problem. That's got to be wiring, coils or coil drivers.
It's just a fine tuning for misfire detection and might make things a
little smoother, but it has nothing to do with a few-cylinder spark
problem. That's got to be wiring, coils or coil drivers.
Coil drivers are just low side switches inside the PCM, that
apply the current (dwell period) and interrupt it (spark
timing). These can go bad, especially if overstressed from
too much dwell (core saturation, current runaway) or a
spark that fails to jump in the gap, and makes the primary
fly back to high voltage.
You'd like to look at the primary voltage on a 'scope with
a high voltage probe, but that's not common gear. The
waveform (or especially its match to the cylinders that
are working right) could tell you some things.
I haven't seen much reporting of bad drivers but it can
happen. I'd eliminate the coils, wires and plugs first by
inspection / swapping.
How are you determining failure-to-fire? I like an old
school clamp-on timing light as an indicator. Reading
plugs may tell you that the cylinder isn't firing, but
this can have causes other than spark electrical.
apply the current (dwell period) and interrupt it (spark
timing). These can go bad, especially if overstressed from
too much dwell (core saturation, current runaway) or a
spark that fails to jump in the gap, and makes the primary
fly back to high voltage.
You'd like to look at the primary voltage on a 'scope with
a high voltage probe, but that's not common gear. The
waveform (or especially its match to the cylinders that
are working right) could tell you some things.
I haven't seen much reporting of bad drivers but it can
happen. I'd eliminate the coils, wires and plugs first by
inspection / swapping.
How are you determining failure-to-fire? I like an old
school clamp-on timing light as an indicator. Reading
plugs may tell you that the cylinder isn't firing, but
this can have causes other than spark electrical.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
Likes: 0
first i used a spark tester and plugged it into each coil, then i swapped left bank with right bank, same cylinders firing, then i unplugged each coil, an using a ohm meter check the ground, constant positive, pcm ground and trigger voltage
turns out all coils are getting trigger voltage some are lower than others, 4 cylinders are firing properly, 3 have low spark, and 1 has nothing
turns out all coils are getting trigger voltage some are lower than others, 4 cylinders are firing properly, 3 have low spark, and 1 has nothing
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Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
Likes: 0
ok well i had pulled the motor, because i thought i had a rod knocking turned out that when i had pull the transmission to replace the front and rear seal i did not put the torque converter bolts on tight enough. so i get every thing all put back together im driving it around sudden the car starts to wanna die if i let it idle. so i hurry back towards my house
and i hear something brake a start banging around as if a bolt where flying around in my bell housing, the car suddenly just powers down completely, no dash light wont crank back up nothing
turns out half of the mount on the starter broke off, not thinking that was the cause of such a power loss i pull the car apart again transmission out intake off looking around checking things, well car ended up sitting for 3 years, now here we are
i have replace nearly everything on the car and this is the problem i am having
and i hear something brake a start banging around as if a bolt where flying around in my bell housing, the car suddenly just powers down completely, no dash light wont crank back up nothing
turns out half of the mount on the starter broke off, not thinking that was the cause of such a power loss i pull the car apart again transmission out intake off looking around checking things, well car ended up sitting for 3 years, now here we are
i have replace nearly everything on the car and this is the problem i am having
If those voltages are the bottoming voltage of the primary side, and
the other side is solid IGN on each, then coils look well driven enough
to me.
Have to wonder if the starter could have been shorted and burned
some power or ground strap out, the go-dark episode suggests a bad
short and consequences. These motors' behavior does get squirrely
with bad grounds. Or maybe the grounds at the back of the head
are just flapping from sometime in the mechanical work.
the other side is solid IGN on each, then coils look well driven enough
to me.
Have to wonder if the starter could have been shorted and burned
some power or ground strap out, the go-dark episode suggests a bad
short and consequences. These motors' behavior does get squirrely
with bad grounds. Or maybe the grounds at the back of the head
are just flapping from sometime in the mechanical work.
1. check the grounds at the head
2. check that the wire harness isn't pinched in the bellhousing
