[AT] Off Topic. Need help with Dodge caravan computer maybe?

Cecil Bearden crbearden at copper.net
Fri May 19 17:35:43 PDT 2017


Thanks to all you guys for the help with my mini van.   Steve W. 
diagnosed it, a crankshaft sensor.  The tach would not show while 
cranking.  I ordered a new crank sensor and then spent a while trying to 
locate it.  I looked at a partial youtube video of a 2005 caravan sensor 
replacement and figured out that I had to remove the battery box. Since 
I have hands the size of a Grizzly paw, I had to also remove the cruise 
actuator and the wiring harness strap to push the wiring down enough 
that I could get my hand near the sensor and the bolt.  It took nearly 2 
hours by the time I got the bolt removed and the sensor pulled.  The 
metal cap on the end was gone.  I think that the sensor end was what 
kept the old starter from engaging.  The new starter quit making the 
terrible grinding noise after more cranking, so I think that the sensor 
cap is now ground up in the flywheel teeth.  It starts with less than a 
second of cranking.   We had noticed earlier that sometimes it would 
crank for more than 15 seconds and finally fire up with a lot of 
stuttering.

I never cease to be amazed at the wealth of knowledge on this list.  
Thanks to you all, I tried every suggestion.

Cecil in OKla


On 5/19/2017 7:38 AM, Cecil Bearden wrote:
> I swapped the relays with the ASD relay yesterday.   Since the plugs are
> dry, I think both fuel and spark are shut down.
>
> Cecil
>
>
> On 5/19/2017 7:16 AM, Doug Tallman wrote:
>> Cecil, There is a relay in the underhood box called an auto shutdown
>> relay. It controls voltage to the ignition coil among a bunch of other
>> circuits. you could check for voltage at the coil or just swap the relay
>> with another similar one from the box and try it first. Doug T
>>
>> On 5/19/2017 8:03 AM, Cecil Bearden wrote:
>>> St eve:
>>> Thanks I will try it.  My thoughts are that the charging syst em
>>> grounded through a sensor.
>>>
>>> Cecil
>>>
>>>
>>> On 5/18/2017 10:56 PM, Steve W. wrote:
>>>> Cecil Bearden wrote:
>>>>> I know a lot of you guys have more experience with the computer systems
>>>>> than I have.  I have suffered through Youtube videos of nearly every
>>>>> self described ëxpert"in diagnosing a no start condition.  Here's the
>>>>> timeline of what has been replaced and what happened.  Wife's 2003 Grand
>>>>> Caravan w/ 3.8L V6 130000 miles.  Sat Morning, alternator making loud
>>>>> whine heard 40 yds away.  Alternator would burn your fingers after
>>>>> running only 4 minutes.  Dropped Alternator and found noisy water pump
>>>>> also leaking when inspecting other pulleys.  Replaced alternator and
>>>>> water pump after bolt broke off on water pump.  Drilled it out Sat night
>>>>> with cordless screwdriver and hex chuck style bits.  Had partial threads
>>>>> so used a longer bolt and put a nut on back side.   Got it back together
>>>>> on Sunday and had to wait until Mon morning to get some Christmas tree
>>>>> fasteners to hold the belt shield.  Tuesday my wife drove it nearly 150
>>>>> miles in OKC and made at least 15 stops running errands with no
>>>>> problems.  Arrived at front gate and engine died.  Would not start when
>>>>> cranking.  It is possible she stopped and backed up when it died, ( just
>>>>> info for later )  but I cannot confirm.  Found battery ground cable
>>>>> loose after engine would not crank.  Tightened cable and cranked
>>>>> engine.  After several tries the starter would just spin and not engage
>>>>> the flywheel.   Wednesday got reman starter and spent 3 hours removing
>>>>> the old one.  I installed the new starter this morning, and it would
>>>>> crank but not start.  The new starter really grinds, sounds like it is
>>>>> coming apart.  Removed spark plug and cranked with spark plug
>>>>> grounded.   No spark.  Changed ignition coil and still no spark.
>>>>>
>>>>> I don't know where or how to start looking.  Since the battery cable was
>>>>> loose and I took off the ground to install the starter, the codes are
>>>>> not in the computer.  I don't find any method for testing the ECM.
>>>>> There are some forum discussions on the flex plate cracking around  the
>>>>> crankshaft in an octagon pattern and the flex plate shifting.  When this
>>>>> happens, the crank position sensor works on the flex plate, and is then
>>>>> out of time with the cam position sensor.   I cannot find an inspection
>>>>> plate to look at the flex plate.  It would be a 2 day job for me to
>>>>> remove the transmission to look at the plate.  However, I wonder about
>>>>> the original starter just spinning and then the replacement sounding
>>>>> like it is about to fly apart.  If the flex plate is not right, the old
>>>>> starter might have not been able to mesh and the new one is meshing but
>>>>> in a bind.  The old starter had to be pried out of the housing as the
>>>>> nose of the starter was nearly pressed into the bell housing.  The new
>>>>> one was easily pushed into the housing.   So far I have lost over 3 days
>>>>> and nearly $500 working on this when I need to be working on the swather
>>>>> and the water pump on the 1270 Case to pull the swather.  An ECM is
>>>>> another $400, and replacing the flex plate will be at least $600 because
>>>>> I need to send it out.
>>>>> Has anyone had any experience like this?   I know if I take it to the
>>>>> stealership, I will be out $1000 by the time they get done.  I don't
>>>>> have an independent mechanic here I can trust, and if I have to spend a
>>>>> bundle on this car, I am about ready to buy a new one and try to get a
>>>>> 20 year extended warranty!!!  Then maybe I can get some work done.
>>>>>
>>>>> Cecil in OKla
>>>> Grab a voltmeter. Turn on the key and test the crank sensor for power
>>>> and ground, It is on the bellhousing right below the crossover pipe for
>>>> the exhaust. 3 wires, Brown/Pink is 8 volt bias voltage, Dark Blue/Dark
>>>> Green is the ground. Brown/Light Blue is the signal wire. If you have a
>>>> scope you would see a square wave on that line.
>>>>
>>>> Easy cheat IF it has a tach, Does the tach move at all while cranking?
>>>>
>>>> Next, disconnect the battery. Hold the two cables together for about 30
>>>> seconds, this will drain the KAM capacitors. Now reconnect the cables.
>>>> Turn on the key and lock/unlock the doors twice.
>>>> See if it starts. You may need to step on the throttle if it acts like
>>>> it wants to start because it will need to relearn the TPS output again.
>>>>
>>>> csr684  at  yahoo  dot com  if you wish to continue.
>>>>
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