99 Chrysler 300M 3.5L - Cranks, will not start

Ok, I am at a loss. Son called me from a friends house and said car
wouldn't start, was running fine when he shut it off, got ready to
leave 2 hours later and nothing.

Went over to check things out, motor turned over normally, almost
started "kinda acted like it is just not getting enough fuel" but
would not run. Threw the car on a trailer, brought it to the house.
Checked fuel pressure at the rail (46-48psi and holds for over 5
minutes) put OBDII scanner on the car, no codes. Checked spark, got
spark on all 6 cylinders. Checked injector pulse, (this is where it
gets strange) on cylinders 1 and 2 I get 1 pulse on intial crank then
nothing. Was really liking the cam or crank postion sensor for this so
I back probed the cam position sensor and got a fluctuating 5vdc,
checked crankshaft position sensor, nothing, pulled it and replaced,
now I got good crank PS signal, went back to injectors, 1 and 2 now
get erratic pulse (and I say that by comparison... because what I
would expect to see, I don't so I worked my way toward the back
cylinders... 3 and 4 seem more like what I would expect, but something
still just doesn't seem right, so checked 5 and 6 and got more of what
I would expect to see and I say that with this caveat.. I almost watch
the noid light in shock, because I would not expect to see it react
the way it does (borderline to much for just cranking the motor
over).

The only thing I have left to check is compression, thinking that
would indicate whether timing belt took a dive (I shudder at this
thought, but the car has 189,000 miles on it and has been very
reliable). However... I have spark and unless I am missing something
there is no way I am getting spark if its broke AND coupled with the
cam position sensor giving me the a flucuating 5v reading when I turn
the motor over with a breaker bar. Also, for S&G, checked resistance
on both sensor outputs to ground got no short on either.

I am leaning more towards the ECM at this point, and I have seen them
just take a dive, but not willing to go out on a limb and drop $250
without SOMETHING definitive.

Is it possible for a Chrysler shop to bench the ECM off the car?

Is it possible for it to jump time and cause the injector pulse to act
this way?

I am at a loss...

wrote:
> Ok, I am at a loss. Son called me from a friends house and said car
> wouldn't start, was running fine when he shut it off, got ready to
> leave 2 hours later and nothing.
>
> Went over to check things out, motor turned over normally, almost
> started "kinda acted like it is just not getting enough fuel" but
> would not run. Threw the car on a trailer, brought it to the house.
> Checked fuel pressure at the rail (46-48psi and holds for over 5
> minutes) put OBDII scanner on the car, no codes. Checked spark, got
> spark on all 6 cylinders. Checked injector pulse, (this is where it
> gets strange) on cylinders 1 and 2 I get 1 pulse on intial crank then
> nothing. Was really liking the cam or crank postion sensor for this so
> I back probed the cam position sensor and got a fluctuating 5vdc,
> checked crankshaft position sensor, nothing, pulled it and replaced,
> now I got good crank PS signal, went back to injectors, 1 and 2 now
> get erratic pulse (and I say that by comparison... because what I
> would expect to see, I don't so I worked my way toward the back
> cylinders... 3 and 4 seem more like what I would expect, but something
> still just doesn't seem right, so checked 5 and 6 and got more of what
> I would expect to see and I say that with this caveat.. I almost watch
> the noid light in shock, because I would not expect to see it react
> the way it does (borderline to much for just cranking the motor
> over).
>
> The only thing I have left to check is compression, thinking that
> would indicate whether timing belt took a dive (I shudder at this
> thought, but the car has 189,000 miles on it and has been very
> reliable). However... I have spark and unless I am missing something
> there is no way I am getting spark if its broke AND coupled with the
> cam position sensor giving me the a flucuating 5v reading when I turn
> the motor over with a breaker bar. Also, for S&G, checked resistance
> on both sensor outputs to ground got no short on either.
>
> I am leaning more towards the ECM at this point, and I have seen them
> just take a dive, but not willing to go out on a limb and drop $250
> without SOMETHING definitive.
>
> Is it possible for a Chrysler shop to bench the ECM off the car?
>
> Is it possible for it to jump time and cause the injector pulse to act
> this way?
>
> I am at a loss...

They have 189k miles on it on the original timing belt!? Forgive me,
but if it did break, they would deserve a few bent valves. Change
interval is 100 or 105k - depending on year - and they do not like to go
much beyond that.

I believe you'd still get spark based on the crank position sensor even
if the cam position sensor is not getting blipped (not 100% sure about
that, but I think I'm right).

You can partially remove timing cover to inspect for broken or slipped
belt, but at that mileage, it would be a miracle if it isn't broken.

Sounds like it was at low speed (which is often when they break) which
would lessen the likelihood of bent valves if it is the belt.

--
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Bill Putney > writes:

<snip actual problem>

> I believe you'd still get spark based on the crank position sensor
> even if the cam position sensor is not getting blipped (not 100% sure
> about that, but I think I'm right).

This isn't clear from the FSM -- the ignition timing is based on the
crank sensor, but which piston will be at TDC comes from the cam sensor.

Though if the timing belt has failed I'd expect a code from the
resulting cam-to-crank sensor misalignment (I don't see anything in the
FSM that looks definitive to me about whether that'll detect the case
that no cam sensor input is happening, though).

> You can partially remove timing cover to inspect for broken or slipped
> belt, but at that mileage, it would be a miracle if it isn't broken.
>
> Sounds like it was at low speed (which is often when they break) which
> would lessen the likelihood of bent valves if it is the belt.

That would be very lucky, to say the least -- my daughter's Neon, with a
4, passed a compression test after breaking a timing belt, but burned a
hell of a lot of oil ever after. I'm not sure it's even possible to
break a timing belt on a 6 without bending valves.

Joe Pfeiffer wrote:
> Bill Putney > writes:
>
> <snip actual problem>
>
>> I believe you'd still get spark based on the crank position sensor
>> even if the cam position sensor is not getting blipped (not 100% sure
>> about that, but I think I'm right).
>
> This isn't clear from the FSM -- the ignition timing is based on the
> crank sensor, but which piston will be at TDC comes from the cam sensor.

You could be right. It seems that I've read posts on one of the LH car
forums by people who know that it is possible, though I couldn't tell
you what secondary backup source the computer could possibly use to sync
the pistons to the ignition - and it is entirely possibly that I am
mis-remembering. I guess, as you suggest, I could imagine it (as a
temporary or limp mode) being able to sync up with no crank signal
before I could imagine it syncing up with no cam signal. On the other
hand - it doesn't run at all now.

> Though if the timing belt has failed I'd expect a code from the
> resulting cam-to-crank sensor misalignment (I don't see anything in the
> FSM that looks definitive to me about whether that'll detect the case
> that no cam sensor input is happening, though).

I do know for a fact that it is often reported on the LH forums that a
bad cam or crank signal will not always throw a code. In this case
since it was a sudden no-run event, the PCM may not be seeing enough
information to set a code - though it would seem that enough info. is
there for it to know something (which is no good if the firmware doesn't
exploit the info.), but nevertheless it is known not to under a few
failure scenarios (bad position sensors being one of them, though bad
position sensors sometimes will set a code, and I think broken timing
belt will not set codes - again, could be mistaken).

>> You can partially remove timing cover to inspect for broken or slipped
>> belt, but at that mileage, it would be a miracle if it isn't broken.
>>
>> Sounds like it was at low speed (which is often when they break) which
>> would lessen the likelihood of bent valves if it is the belt.
>
> That would be very lucky, to say the least...

The broken timing belt threads we see on the LH car forums very often
report the event happening immediately at startup or at low speeds (not
difficult to imagine that the more pulsatile/high-peak stresses on the
timing belt would occur at the lower speeds when smoothing flywheel
effects on the cam are for all intents and purposes absent.

> ...-- my daughter's Neon, with a
> 4, passed a compression test after breaking a timing belt, but burned a
> hell of a lot of oil ever after...

Strange. Do you have any idea why that would be? I'm having trouble
thinking of the connection between the timing belt failure and burning
oil. Not doubting - just trying to visualize. I guess it is possible
that the two just happened to start occurring around the same time.

> ...I'm not sure it's even possible to
> break a timing belt on a 6 without bending valves.

Yes - it definitely is possible - we see broken timing belt threads in
which the valves were *not* bent as well as ones in which they *were*
bent. Obviously the chances of successfully "running between the
raindrops" is statistically greater at low speed based purely on the far
fewer number of after-break revolutions of the crank and cams from
flywheels effects on both. I get the impression that the of crank
rotation degrees of possible interference-to-360° ratio is rather small
which would of course, combined with breakage at low-speed operation,
decrease the chances of valve/piston disagreements during the event.

--
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Bill Putney > writes:

> Joe Pfeiffer wrote:
>
>> ...-- my daughter's Neon, with a
>> 4, passed a compression test after breaking a timing belt, but burned a
>> hell of a lot of oil ever after...
>
> Strange. Do you have any idea why that would be? I'm having trouble
> thinking of the connection between the timing belt failure and burning
> oil. Not doubting - just trying to visualize. I guess it is possible
> that the two just happened to start occurring around the same time.

My guess was valve guides -- lots of blue right after startup.

>> ...I'm not sure it's even possible to
>> break a timing belt on a 6 without bending valves.
>
> Yes - it definitely is possible - we see broken timing belt threads in
> which the valves were *not* bent as well as ones in which they *were*
> bent. Obviously the chances of successfully "running between the
> raindrops" is statistically greater at low speed based purely on the
> far fewer number of after-break revolutions of the crank and cams from
> flywheels effects on both. I get the impression that the of crank
> rotation degrees of possible interference-to-360° ratio is rather
> small which would of course, combined with breakage at low-speed
> operation, decrease the chances of valve/piston disagreements during
> the event.

Good to know (though I sure hope I never have occasion to test it!).

Joe Pfeiffer wrote:
> Bill Putney > writes:
>
>> Joe Pfeiffer wrote:
>>
>>> ...-- my daughter's Neon, with a
>>> 4, passed a compression test after breaking a timing belt, but burned a
>>> hell of a lot of oil ever after...
>> Strange. Do you have any idea why that would be? I'm having trouble
>> thinking of the connection between the timing belt failure and burning
>> oil. Not doubting - just trying to visualize. I guess it is possible
>> that the two just happened to start occurring around the same time.
>
> My guess was valve guides -- lots of blue right after startup.

But can you figure out a connection to the timing belt breaking? I can't.

--
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Hi!

> I guess, as you suggest, I could imagine it (as a
> temporary or limp mode) being able to sync up with no crank signal
> before I could imagine it syncing up with no cam signal.

If GM could do it on the late 80s 3800 V6, I'd have to think that Chrysler
could find a way to do it as well. (I have two Buick cars--an 88 and an
89--that both have something wrong with the cam sensing. (It doesn't seem to
be the sensor.) They will run and drive fine. But the ECM can't enter
sequential fuel injection mode without a report from the cam sensor, so it
sets a code.)

But that's neither here nor there, I'm just throwing it out.

William

"William R. Walsh" m>
wrote in message news:CmmTl.717303$yE1.515731@attbi_s21...
> Hi!
>
>> I guess, as you suggest, I could imagine it (as a
>> temporary or limp mode) being able to sync up with no crank signal
>> before I could imagine it syncing up with no cam signal.
>
> If GM could do it on the late 80s 3800 V6, I'd have to think that Chrysler
> could find a way to do it as well. (I have two Buick cars--an 88 and an
> 89--that both have something wrong with the cam sensing. (It doesn't seem
> to
> be the sensor.) They will run and drive fine. But the ECM can't enter
> sequential fuel injection mode without a report from the cam sensor, so it
> sets a code.)
>
> But that's neither here nor there, I'm just throwing it out.
>
> William
>
>

My aunt's '92 Buick Regal Custom with the 3.8/3800 series I has the MIL on
for the same reason. It came on when I floored it to merge back onto the
interstate while coming back to Iowa from Oklahoma and has been on ever
since. Strangely enough the car seems to run better now than it did before
as before it would chug and sputter for the first ~30 seconds after being
started and now it starts right up and idles smoothly.

replying to hightide610 , Combat Missionary wrote:
If you haven't actually jumped time, then...

Apparently a lot of Chrysler 300M's at one point or another go through a
problem similar to this. The symptoms include (often in this order):

Acting like the rev limiter is turning on at greater than approximately 2,500
RPM

Rough idle followed by engine shutdown and inability to start

The Fuel Shutdown and/or Automatic Shutdown Relay clicking on and off multiple
times per second or every couple of seconds

Intermittent spark when cranking the engine

Trouble codes for crankshaft position sensor fault, camshaft position sensor
fault, or both

People will try replacing the crankshaft position sensor, the camshaft
position sensor, or both, followed by the ECM (Engine Control Module), and the
car may start up, then stop working again. This will make you pull your hair
out.

I just went through this problem myself, and I was finally successful in
correcting the fault. If you follow this procedure, you will be too.

Pull the battery and clean and tighten the terminal clamps. Clean the
negative cable jump terminal on the passenger side fender under the hood.
Clean the terminals connected to the positive jump terminal in front of the
air cleaner assembly. Clean the positive cable terminal feeding power into the
power distribution center (PDC). Test your battery and make sure it is
charged. Lack of power due to a discharged or bad battery or corroded
terminals will prevent adequate spark and will stop cranking. After cleaning
these terminals, try starting the car. If the car still doesn't start, proceed
to step 2.

Test fuel pressure at the fuel rail while having an assistant crank the
engine. Upon startup, the fuel pump will pressurize for approximately 3
seconds, so this test is simply to eliminate a bad fuel pump as the cause of
your non-start. You will probably read in the neighborhood of 50-60 PSI if the
fuel pump is working.

Test for spark at one of the coil packs. If you have no spark, your ASD
relay is probably not getting a ground.

Following the procedure outlined in the Haynes or Chilton's repair manual
for your car, test your camshaft position sensor and your crankshaft position
sensor. One wire feeds approximately 8 VDC to the sensors, one wire grounds
the sensors, and one wire sends a square wave (approximately 5 VDC) to the
ECM. This test involves “backprobing� the connectors, but you can simply
use a voltmeter and push GENTLY through the wire insulation (if you push too
hard, you'll break the copper wires inside and create a high resistance wire
which will be more of a pain to fix) and test for power and/or ground as
specified by the manual.

Test the ASD relay.

Resistance test terminals 85 and 86. You should read about 75 ohms of
resistance.

Resistance test terminals 87 and 30. They should read open (infinite
resistance).

Jumper terminal 86 of the relay to 12 VDC, and jumper 85 to ground.
Resistance test terminals 87 and 30. You should read continuity (roughly 0
ohms of resistance).

If the relay meets these specifications, the relay is good. If not,
replace the relay.

Test the Fuel Pump Relay using the same procedure as with the ASD
relay (the terminal numbers are the same and the relays operate the same, even
thought the Fuel Pump Relay is narrower).

At this point, you'll have established that you have a good battery, good
power distribution, a good fuel pump, a good crankshaft position sensor, a
good camshaft position sensor, and good ASD and Fuel Pump relays. If your car
still won't start, and you're still reading bad crankshaft and camshaft
position sensor codes, and you're still getting “chattering� ASD and Fuel
Pump relays, it's because the relays are getting an intermittent ground
through the ECM. Most likely your problem is that there is a fault in the
engine wiring harness that has shorted and ruined your PCM. The harness must
be repaired and then the ECM must be replaced. If you just replace the ECM
without repairing the harness, odds are you'll just fry the new one.

To remove the harness, first remove the upper intake manifold. Place clean
rags in the intake holes on the lower intake manifold to prevent debris from
entering the manifold. Disconnect the C1 connector from the ECM (this goes to
the engine, the C2 connects to the PDC). Follow the harness and disconnect it
from the PDC connectors, the alternator, fuel injectors, coil packs, upstream
O2 sensors, throttle body, etc. Note the portion of the engine harness that
passes under the upper radiator hose connection at the lower intake manifold.
On my 300M, the insulation on about half of the wires at this point had been
melted due to the heat from the engine coolant passing through the hose.

Repair the harness. Separate the individual wires from each other. Wire by
wire, cut out any parts that have melted or brittle insulation. Solder and
heat shrink replacement wires into place.

After repairing the damaged portions of the wiring in this section of the
harness, inspect the rest of the harness for cracked, brittle insulation,
melted insulation, chafed insulation, etc. Repair the wires as necessary (this
part took me a couple of evenings in my shop). Inspect all of the connector
plugs for damage, missing lock tabs, or any other damage. You can still get
most of the connectors at a dealer, so replace them as necessary (I found
about half a dozen wires that were chafed at the connector plug and were
probably grounding out on my harness; any of these could have fried my ECM),
although if you need a C1 connector, you're going to have to go to a junkyard
and splice it in (I didn't need one). Use solder and heat shrink, or you'll
just end up redoing the job when your crimped splices corrode out.

After repairing all the wires in your engine harness and replacing any
connectors as necessary, chafe wrap your rebuilt harness. Between Auto Zone,
O'Reilly's and Harbor Freight, I got plenty of 1/4�, 3/8�, 1/2� and
3/4� plastic anti-chafe corrugated tubing (or whatever it's called). Chafe
wrap every sensor lead right down to the sensor and secure the chafe wrap with
zip ties. After chafe wrapping the entire harness, use plenty of electrical
tape where sections of chafe wrap meet to secure the sections together.

At this point, you have a harness that's probably better than factory.
Reinstall the harness, rerouting it ABOVE the upper radiator hose and pushed
forward more so you don't get melted wiring again anytime soon from radiated
manifold heat. Reconnect the harness to your ECM (you might get lucky and NOT
have a fried ECM). Try to start the car. If you're still getting the
chattering relays, your PCM is shot. I recommend going to Auto Zone for a new
one. Dodge wanted $500 for the part, plus another $100 to flash program the
ECM; they wanted $900 to install and program the ECM themselves. O'Reilly's
wanted $130 for the ECM, $20 to ship it in from out of state (plus a three-day
wait), and then I'd have to take it to Dodge to flash program it. AutoZone had
the part I needed for $130, and when I went in, I brought in my VIN and my
mileage, they got me the part in three days already flash programmed from the
remanufacturer. It works like a charm, plug-n-play. Just install the part and
you're ready to go.


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