2000 Dodge Ram Van 360 burn out coils

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Points
16
This van has burned out 4 coils in 2 weeks. When I replaced the first coil I did a tune up at the same time. Thought the problem was fix, week later died again. Now if you replace the coil it will burn it out in less that five minutes. If you let the van sit with the key on the coil seems to get very hot. The coil has a two wire connector. Any ideas what to check.
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,919
Points
48
Age
119
Hey Keith:
lets get some info to help us help you.

1)Is the CEL (ck eng lt) on? Confirm it will come on when starting then go out in @3seconds..its important..
2) the vehicle is STOCK - no aftermarket parts proms, chips, miracle promises - alarms, REMOTE start?
3) those coils and full tune up parts - OEM?

I suspect that there will be modifications OR at the least some codes... I will pull up a tech sheet while I wait for answers 1,2,3

to get something started- at coil unplug harness - using DVOM ck if BLK/GRY wire is grounded? shake wire to see if intermittant ground.
 

Mobile Dan

wrench
Joined
Mar 1, 2002
Messages
3,665
Points
48
Location
Kentucky
If the coil gets really hot if you leave the key on, the ASD (auto shut down) relay must be bypassed or "stuck on", because the way it should work is this...If the key is turned on, but the engine is not started, the ASD will be energized for about 1 second, then de-energized. If you listen carefully, you should hear the fuel pump run for that 1 second, then stop, even though the key is still on.

The coil may be designed to run while sharing power with injectors and other things...full current may cook it.

What kind of system voltage is your alt putting out?

Are you SURE that is the proper coil? Some coils look very similar but are not the same.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,659
Points
48
Is this a new problem, or is the vehicle new to you and came with the problem? Even if there is an ASD that cuts power to the coils (some cars don't cut coil power that way), and it is bad or bypassed, the ECM should also be preventing current through the coils when the engine isn't rotating. The coils are only energized for a brief "dwell" period before firing, just long enough to saturate the coils magnetic core. This is typically 10msec or less. Since the ECM usually grounds the coils to energize them, kev2's suggestion to check for shorts on the grounding side makes a lot of sense. That's assuming everything is stock, and coils are correct, of course...
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Points
16
Thanks for the ideas. Checked the PCM for codes found none. It has a added remote to unlock doors. I remove this because it did not work anyway. Checked the battery voltage while running 17 volts. I am thinking that would burn out a coil. It hit 18volts when I raised the rpms. I think the regulator is in the PCM on Dodges.
 

NickD

wrench
Joined
Aug 28, 2007
Messages
4,893
Points
48
Don't know anything about Chrysler, practically all DIS systems have zero current when idle, requires a pulse to switch on normally a gated bipolar transistor. Practically all the latest ones use the bipolar as a current source permitting a much lower primary resistance. Transistor should be okay if the vehicle is running.

Can only speculate with the correct coil, the dwell is way off to high that would cause those coils to overheat. Contrary to popular believe, dwell is still used in the design of ignition systems, but since it is not user adjustable, no longer specified. By any chance is Chrysler still using ballast resistors? Just guessing.

Having coil high coil resistance became part of history to limit coil current, that resistance just wasted power, a current pulse eliminates most of that waste.
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,919
Points
48
Age
119
18 v thats not good....

Your correct the PCM controls Alternator...
What does the dash voltage gauge show?
you use a scanner ? thinking some codes may not set MIL... ie p0563, p0515

DO you need a circuit dia ? - hoping as I always do its something other than PCM/ECM
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,659
Points
48
I agree, 18V is a problem; might be because of the PCM, and might have fried other things in the PCM. However, that voltage would not cause the coils to get hot when it is KOEO. There should be no coil current when the engine isn't rotating, so a too-high voltage wouldn't require the coils to dissipate any more power than normal in that mode.
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,919
Points
48
Age
119
seams like several things going on, answering questions would help focus (esp me), any chance battery going dead? you did not ans - CEL operation ? Parts OEM ? MODIFICATIONS aftermarket esp things like MSD ign, added tach,

Can you clear up-
Your coil - you say with key off it STILL overheats?
As mentioned there should be NO voltage to coil with key off, it will also lose power after several seconds if ENG not running- as mentioned ASD relay - DANICA described ciccuit in above post


Overvoltage- yes the PCM controls alt,
I asked about scanner, what voltage is the PCM seeing it whould NOT energize (grd) alt if it sees 18v,
SO is PCM reading voltage OR only seeing an open ie lower voltage... ck wiriing dia
 

Attachments

LynnM

Sr. Member
Joined
Nov 16, 2006
Messages
209
Points
18
Fix your voltage regulator first... I would change the ASD relay and the regulator (PCM) although there is a way to add an external regulator to the PCM I do not have the info handy-- do an internet search
18 volts will kill the coil...

http://www.alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

"My engine management computer on my Dodge/Chrysler vehicle is no longer making my alternator work, Is there a way to wire or connect an external voltage regulator to my Dodge or Chrysler vehicle?
erck diagram

Yes you can use an early (late 70's early 80's) Dodge/Chrysler electronic external voltage regulator like our part number c8313. To make it work you just need an ignition wire run to both the voltage regulator "I" connection and to one of field connections (brushes) on the alternator. The "field" connection on the voltage regulator is run to the other brush (field) connection.

This is an "A" circuit type voltage regulator which means full power is sent to one brush while the voltage regulator controls the output by varying the ground to the other brush. It does not matter which wire you run to the regulator field connection and which one you ground, you can swap them around. The external regulator will make your alternator work
 

NickD

wrench
Joined
Aug 28, 2007
Messages
4,893
Points
48
"A" circuit field connections were preferred by some dumb engineers because a much cheaper N-channel power MOSFET transistor could be used to switch the field circuit. We didn't buy that because with the high side of the field always hot, electrolysis can form across the slip rings. At GM, we used an integrated circuit voltage doubler that cost practically nothing to use an N Channel in the common source connection. Required at least 8 V above the battery voltage to make sure the pass transistor was fully saturated.

If you see bits of copper between the slip rings, that will bypass the pass transistor and tend to full field the alternator causing the over voltage where the pass transistor loses complete control. A really dumb idea.

Was a push for PCM controlled voltage regulators, could use the same AD converter in the PCM microcontroller and the engine diagnostics for error codes. Also the ambient sensor used for the AC system and OAT gauge could be used to control battery charge voltage. But also required serialized bytes to be converted parallel with an additional DA converter to fired the N-Channel, a far more complicated voltage regulator. And since that serialized data feeding high impedance FET's, subject to EMI. Shielding was normally out, so routing is the way to minimize that.

Mounting the VR in the alternator was never a good idea. but those four wires required to mount the regulator near the battery were treated like a billion dollar expense. VR's have thermal sensing and never did a good job of monitoring the battery temperature with as many as eight super hot diodes in the same package. Just on some Caddies were we allowed to add a couple of wires for a remotely mounted thermistor placed near the battery.

Just typing this so you know some of the reasons you are having problems.

Was invited to a very expensive country club with all the executives there, order anything you want, drink all you want. Then was hit about reducing cost. Just looked around and smiled and replied, we could just as well have this meeting at Macs. That went over like a lead balloon. Not joking on this.
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Points
16
Let me up date. I do not think the coil is getting voltage if the key is off. It got so hot so fast I thought it must be heating up with the key on, it accutally melted the plastic. I put a test light in place of the coil and the light goes off if the crank sensor looses signal. So as soon as that engine stops rotating power is cut to the coil. The relay seems to be working and the battery is not going died.

yes, check engine light comes on then goes off in 3 seconds, no codes, parts are from Car Quest, engine and van are stock- someone had added remote for door locks and power windows, I removed both, they were not working anyway,

I plugged in scanner and see what voltage the PCM is seeing, good point here. Scanner said "battery Voltage 0.0" "Desired Voltage 13.6"

The only other problem is if the voltage 17v the volt meter on the dash or insterment panel reads 0v. If the alternator is regulated and battery voltage is around 13.5 volts the dash is up and reading.

I will be looking at power wires feeding the PCM and dash.

thanks
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Points
16
Since the scanner was reading 0v. I checked the voltage on C25 at the computer. This is a generator source wire and it has battery voltage. I also checked the fuses 8,4, and 7 and they were all good. I am not able to find a connection between the gauge on the dash and the PCM. But I feel the PCM is the likely cause of the problem now. I would be open to any more suggestion or idea of anything esle to check.
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,919
Points
48
Age
119
seams to me two issues here - likely connected...

The coil - What is the voltage to coil key on, remember only powered briefly ...
as the coil is only 2 wires - unplug and probe BOTH with DVOM cking Volts and ground.
knowing that may have us look into coil application.

The charging issue- is it intermittant, when the dash gauge and scanner reads 0 only then does it go to that critical high charge rate? I think the PCM is not seeing the battery V and commanding the alt to go full charge.... A problem in the PDC corossion I recall was an issue.... later I will ck TSBs and known issues that match the no voltage seen by PCM
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Points
16
I think it is just one problem the high voltage is what is burning out the coils.
 
Top