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ECU Dead? Why?
#1322402
10/18/12 06:27 PM
10/18/12 06:27 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
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OP
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North Carolina
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Guys, I have been troubleshooting electrical gremlins on my Charger now for a few weeks and I thought I had them figured out... Right now I have an issue where the car will die after 10-15 minutes of running. The idle will start getting real rough and she just dies. This was the case before and I swapped out the ECU on the firewall and problem solved or so I thought.... No the problem is back. This time I can restart the motor but it won't idle (cuts off) and if I rev it up, it goes up but then after coming down it dies. Cranking the car from cold, everything acts normal until it warms up. Now, what I did do (stupid me) was leave the key in the run position over night (12hrs or so) and needless to say, my battery was dead. I charged it back up with a battery charger and fired it up and now the issue is back. Could that kill the ECU? Could this be a coil issue? This is a brand new $20 parts store ECU. I can't imagine that sucker was bad outta the box. I drove it 20-30 minutes on it before this incident and the Charger ran fine... Can anybody help point me in the right direction? I have pretty much ruled out grounding issues and the charging system. System was charging when it dies so its not a dead battery...plus I can crank it after it dies all day. Please 
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Re: ECU Dead? Why?
[Re: dogdays]
#1322405
10/18/12 07:06 PM
10/18/12 07:06 PM
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Joined: Apr 2010
Posts: 4,154
bethlehem pa
mikemee1331
master
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master
Joined: Apr 2010
Posts: 4,154
bethlehem pa
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Quote:
Coil is failing. I've seen it before. The engine starts fine and when the coil reaches a certain temperature the coil stops working.
R.
 and leaving it powered on for 12 hours with no discharging is the reason.
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Re: ECU Dead? Why?
[Re: dogdays]
#1322407
10/18/12 08:45 PM
10/18/12 08:45 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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 this is where i yank the ecu plug and ditch the ecu. drop in a points dist hooking the dist wire to - side of coil,just remove the stock wire that is there on the - side of coil. hit the key and ride. when I get the funds up, I jump the BR for a full 12 volts to coil and add an pertronix points conversion with the 40,000 volt flamethrower coil. done this a bunch of times on mine and others mopars on the side of the road with a points dist. but once converted to pertronix I have never had to work on any ign., problems again. if I stay with points,i do have to reset them every 3 months or so but thats the way point are. been running the pertronix set up for the last 17 yrs now and for a tune up it gets a cap/wires/plugs only. never mis-fires and will spin 7000rpm+ good luck changing stock ign. parts out.  
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Re: ECU Dead? Why?
[Re: ahy]
#1322410
10/18/12 11:28 PM
10/18/12 11:28 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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I don't know where you all are buying your parts, but in over 20 years of driving MoPars I have replaced 1 coil, zero ecu's and zero ballast resistors. Quit buying junk.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: ECU Dead? Why?
[Re: dart4forte]
#1322412
10/19/12 07:57 AM
10/19/12 07:57 AM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
pro stock
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OP
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Quote:
Try checking your grounds
Before this problem crept up again, I did notice my ground wasn't good on the ECU but I fixed that.
Problem unchanged. I am guessing maybe I smoked it or I am getting lucky with bad parts here...
I went ahead and put nuts on the back of the bolts that secure the ECU to the firewall as my holes are about stripped from all this ECU musical chairs.
This problem really is a PITA because I don't know if it's going to cut off until the it does which leaves me stranded on the side of the road until I can get her to crank. 
I guess my car will get a lot of press around town as it seems to be stuck on the side of the road more often than not.
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Re: ECU Dead? Why?
[Re: RemCharger]
#1322414
10/19/12 12:26 PM
10/19/12 12:26 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Marysville, O-H-I-O
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hard to say for sure, could be anything. but, something electrical is not likeing the heat.
what happened to me was similar, when the car got hot, it started missing, backfiring, and running like crap. it finally stalled and wouldn't re-start.
after it all cooled down, the car started right up.
I replaced the coil because someone here said the coil was breaking down when it got hot.
problem never came back.
**Photobucket sucks**
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Re: ECU Dead? Why?
[Re: RemCharger]
#1322415
10/19/12 12:26 PM
10/19/12 12:26 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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Re: ECU Dead? Why?
[Re: mikemee1331]
#1322416
10/19/12 12:31 PM
10/19/12 12:31 PM
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Joined: Jan 2003
Posts: 6,018
Morningside
AdventurerSport
waaaay out there in left field
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waaaay out there in left field
Joined: Jan 2003
Posts: 6,018
Morningside
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Quote:
Quote:
Coil is failing. I've seen it before. The engine starts fine and when the coil reaches a certain temperature the coil stops working.
R.
and leaving it powered on for 12 hours with no discharging is the reason.
turning the key to "RUN" energizes the coil, leaving it there for 12 hours can ruin a coil. Swap coil and you'll be fine. I've had the same problem with my black '76 Power Wagon years ago. Good luck!
JS
76 Dodge Adventurer Sport Power Wagon W100 318, 727, NP203 Fulltime 4x4 Russet Red
06 Jeep Commander Ltd 4x4, 5.7L Hemi, QuadraDrive II
06 Chrysler 300C AWD 5.7L Hemi
10 Mopar 10 Challenger R/T, #483/500, 5.7L HEMI
10 Jeep Grand Cherokee Ltd 4x4 5.7L HEMI
11 Dodge Ram 1500 LoneStar Quad Cab, 5.7L HEMI, Fulltime 4x4, Deep Cherry Red
16 Jeep Cherokee Limited 3.2L Pentastar V6, 9 Speed Torqueflite, 4x4, Black
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Re: ECU Dead? Why?
[Re: RemCharger]
#1322417
10/19/12 12:55 PM
10/19/12 12:55 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
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OP
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Joined: Jul 2007
Posts: 1,526
North Carolina
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Quote:
You have a ballast resistor?
Yes I do! I went ahead and swapped the coil and ECU after the car got hot and died.
Basically the same deal...doesn't want to start and when it does, idles like crap and dies out again.
I pulled the ballast resistor. Looks like maybe mine has died? I am thinking this could cause my issues...
The "bad" set of terminals (actually used) = 1.8 ohms
The other set (not used) = 5.8 ohms
This is with the ballast cool now. Normal? Needless to say I have one on the way the afternoon.
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Re: ECU Dead? Why?
[Re: cjskotni]
#1322418
10/19/12 01:13 PM
10/19/12 01:13 PM
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Joined: Jan 2003
Posts: 6,018
Morningside
AdventurerSport
waaaay out there in left field
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waaaay out there in left field
Joined: Jan 2003
Posts: 6,018
Morningside
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those can expand when hot as well, causing your problems. Sorry, I thought with Mopars everyone always had spare resisitors and swapped 'em at the first sign of ignition trouble!  I had a Power Wagon with wiring issues, and it would eat resistors and ECUs like candy before I figured out the wiring problems. JS
76 Dodge Adventurer Sport Power Wagon W100 318, 727, NP203 Fulltime 4x4 Russet Red
06 Jeep Commander Ltd 4x4, 5.7L Hemi, QuadraDrive II
06 Chrysler 300C AWD 5.7L Hemi
10 Mopar 10 Challenger R/T, #483/500, 5.7L HEMI
10 Jeep Grand Cherokee Ltd 4x4 5.7L HEMI
11 Dodge Ram 1500 LoneStar Quad Cab, 5.7L HEMI, Fulltime 4x4, Deep Cherry Red
16 Jeep Cherokee Limited 3.2L Pentastar V6, 9 Speed Torqueflite, 4x4, Black
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Re: ECU Dead? Why?
[Re: AdventurerSport]
#1322419
10/19/12 01:23 PM
10/19/12 01:23 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
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Quote:
those can expand when hot as well, causing your problems. Sorry, I thought with Mopars everyone always had spare resisitors and swapped 'em at the first sign of ignition trouble! I had a Power Wagon with wiring issues, and it would eat resistors and ECUs like candy before I figured out the wiring problems.
JS
I know they can cuase issues with the ignition, but I thought when they failed, that was it....no engine run at all...even when cool.
Guess maybe a partial failure that heat brings about?
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Re: ECU Dead? Why? **UPDATE**
[Re: RemCharger]
#1322421
10/19/12 07:44 PM
10/19/12 07:44 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
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OK so replaced/swapped: - ECU - coil - ballast resistor The problem is still there. Car will run for about 10-15 minutes...I can rev it up idle it just fine. Once thing I noticed is that when the electric fans kick on, the engine tends to want to idle lower. I am not sure if the draw from the fans is making this problem worse or not. Funny thing is, I had run fine with these fans and the OEM 60 amp alternator just fine before. I can't see why this would be a charging issue. Also, despite this, the ammeter doesn't show a dicharge at idle until the fans + light are on. The it starts losing and the battery begins to discharge a bit. Still this shouldn't kill the engine. After it cuts off, the motor can still crank so battery isn't dead. Could this be a wiring issue? If so, which wire would cause this so consistantly? I am stuck here. I don't know what else to check. The only thing that has changed since this issue began is the alternator (went to 100 amp unit). However, as I have said before the car dies even when it's reving up (charging) and the battery has PLENTY left.... Checkd grounds, etc...all good. Plug wires are new. Plugs are pretty new as well. Any other ideas??? What else can stop a running motor except for a bad ignition circuit? 
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Re: ECU Dead? Why? **UPDATE**
[Re: dogdays]
#1322424
10/19/12 08:42 PM
10/19/12 08:42 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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If you want to rule out most of the wiring as an issue, simply run a jumper from the battery + to feed side (switched 12V) of the ballast resistor.
This will eliminate everything from the battery to the the ballast. Heck, you could jumper out the ballast to eliminate that too as a temporary test.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: ECU Dead? Why? **UPDATE**
[Re: RapidRobert]
#1322425
10/19/12 08:44 PM
10/19/12 08:44 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
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Quote:
Quote:
Any other ideas??? What else can stop a running motor except for a bad ignition circuit?
dist pickup. I'm assuming the bulkhead has been checked/brass terminals cleaned (small metal bristle brush on the male ones/725147 NAPA male brass 1/4" terminal to clean the female ones)
How does one test a pickup to see if it's bad? Can I look at it and see or just odomething you have to swap to find out?
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Re: ECU Dead? Why? **UPDATE**
[Re: Supercuda]
#1322427
10/19/12 10:26 PM
10/19/12 10:26 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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You could ohm it at the pickup pull apart connector & do it fast while it's still hot. The spec is in the archives. Also put your VOM on low AC volts scale & see if the pickup will generate iirc ~1 volt AC while someone cranks it. Could sub in another pickup/plate or another dist depending on what you have available
live every 24 hour block of time like it's your last day on earth
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Re: ECU Dead? Why? **UPDATE**
[Re: RapidRobert]
#1322428
10/20/12 09:09 AM
10/20/12 09:09 AM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
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Too Many Posts
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Marysville, O-H-I-O
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Ok, so you've replaced the ECU, the coil, the ballast, and are now checking the distributor.
any chance that this is NOT ignition related? maybe it's fuel related? is your tank vents plugged up putting a vacuum on the fuel system, which then causes air to suck in from the carb to relieve the vacuum in the tank. or maybe your carb is heating up too much and you're getting vapor lock?
next time it happens, quickly check for spark. if you have spark, then maybe your problem is not in the ignition system.
**Photobucket sucks**
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Re: ECU Dead? Why? **UPDATE**
[Re: RapidRobert]
#1322429
10/20/12 09:39 AM
10/20/12 09:39 AM
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Joined: Mar 2006
Posts: 9,824
MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,824
MI, usa
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Quote:
You could ohm it at the pickup pull apart connector & do it fast while it's still hot. The spec is in the archives. Also put your VOM on low AC volts scale & see if the pickup will generate iirc ~1 volt AC while someone cranks it. Could sub in another pickup/plate or another dist depending on what you have available
Also swap the box and coil with your original parts during the time when it's failed. My bet is neither part will make it start but you should check. The resistance spec for the pick-up coil is aprox 270 ohms. Ohm testing wiring itself is a poor method. It puts no load on the circuit(amperage). Rig a simple tester with a new style head lamp bulb. Disconnect the circuit you want to test from both ends. Hook one end of the bulb to battery positive, the other end of the bulb/tester to one end of the circuit you want to test. Now ground the other end of the circuit you are testing, the bulb should light. I can't tell you how many wires I've found that went open circuit when heated or placed under load. You can check your entire key fed circuit by placing the bulb after the ballast resistor and grounding the other side of the bulb, then key on. Your problem really should be very easy to find. I bet less than 1 hour.
Doug
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Re: ECU Dead? Why? **UPDATE**
[Re: 70Cuda383]
#1322430
10/20/12 09:42 AM
10/20/12 09:42 AM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
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These are possibilities but I don't think this is fuel related. This is why: - fuel bowls on the carb on a HOT (95 deg) day after running the motor in traffic 30+ minutes were maybe 145 degrees. I don't think that would be hot enough to boil the fuel? Maybe I am wrong here  Either way, then it didn't make the motor die or hard to start... - car was running fine for quite awhile and I have done NOTHING to the fuel system to cause this. Same tank/vents/carb/pump everything. I can try to check for spark next time this happens on one of the plugs and see. I have a new distriibutor pickup on the way. For $20 I will just get a new one and swap it in to see if that fixes my problem. I read some people online had the exact same problem as me ( car would run until warm then die until cool) and it was the dist pickup. Worth a shot I guess. Any other ideas if this doesn't work? 
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Re: ECU Dead? Why? **UPDATE**
[Re: cjskotni]
#1322432
10/20/12 06:44 PM
10/20/12 06:44 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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The rotor looks bent in the pic. I had one like that & I believe it was caused by my carelessness in not setting the cap straight down. I tried to rebend it with no success. It was misfiring/snapping badly. New cap/rotor & all was good. Dont know if I needed to replace the cap as that violated my rule of only 1 part change at a time but I had one handy
live every 24 hour block of time like it's your last day on earth
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Re: ECU Dead? Why? **UPDATE**
[Re: RapidRobert]
#1322433
10/20/12 07:35 PM
10/20/12 07:35 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
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OP
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Quote:
The rotor looks bent in the pic. I had one like that & I believe it was caused by my carelessness in not setting the cap straight down. I tried to rebend it with no success. It was misfiring/snapping badly. New cap/rotor & all was good. Dont know if I needed to replace the cap as that violated my rule of only 1 part change at a time but I had one handy
I think you are on to something. I looked in the cap and the button is all chewed up, thats what those filings are all over the rotor it looks like. I am guessing the bent rotor sanded the button down and maybe enlarged the gap to where the spark couldn't arc across it?
I am guessing maybe when hot, this enlarged gap got wide enough to cause this?
I popped the cap a month or so ago (before this started happening) and the rotor was squeaky clean. I guess I got a bit over excited when I put the cap back on. 
I have a new cap/rotor on order so we will see if this fixes the problem.
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