Ignition Control Module problem

Electrical and Ignition

  1. 360Scamp

    360Scamp Mopar or No Car

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    After the winter I got my car out to get it cleaned up to enjoy the summer cruises and I have had a hell of of a time getting it to run like it did. It has a 360 in it and around 2000rpm it would start to cut out and wouldnt rev any higher. I have tested my ignition module because I tested it and it tested bad. I got a new one from Auto Zone and it does the same thing! I put the old one on and it runs fine. When dealing with this thinking it was my distributor I changed it and put on a new cap, rotor, spark plugs, wires, retimed it. Im just afraid to run the old ignition module seeing how it tested bad, but it makes the car run like it did, I just dont want to get stranded because I have overlooked something simple.
    I need help to find out why my car could be doing this???
    Please help!!!!
    Im really leaning towards going HEI! To eliminate all the old ignition parts
     
  2. tekslk

    tekslk Well-Known Member

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    Retest since its running ok now, probably bad ground that you fixed by removing and replacing parts. Check with trailbeast on his hei conversion and get rid of the parts that give you trouble for a improved ignition system. Best 150 youll ever spend.
     
  3. 360Scamp

    360Scamp Mopar or No Car

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    I have researched and found them on Ebay for around $80
    But if he sells them I will buy from him
     
  4. GEO

    GEO Sarcasm Inc.

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    I myself am a believer in mopar chrome boxes.

    No Orange or parts store boxes for me
     
  5. RedFish

    RedFish Well-Known Member

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    Ignition modules do have intermittent come and go faults. just keep in mind that these things need a full 12 volts supplied and a good ground to operate properly. They need the chassis ground path before the power is applied. Bottom line... Spending for another ignition box may not be the cure.
     
  6. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    These can be difficult

    Like the convoluted thread the other day THIS CAN easily be wiring / connector problems. Check them carefully, visually, and work them in/out several times. Check "feel" for tightness

    One VERY popular problem used to be the distributor pickup connector.

    Personally I run HEI. At the time I tore the car down for paint, I just had a simple 4 wire HEI mounted on the firewall. You can ALSO hide these in a gutted Mopar ECU case.

    Even without running a hotter coil, you can run the FACTORY coil and no ballast resistor, and get more spark out of them.
     
  7. BillGrissom

    BillGrissom Well-Known Member

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    I 3rd the ground connection of the ECU box. Even an HEI module will need its case securely grounded. If you are relying on a rusty sheet metal screw, you will have continual problems, especially where you live.
     
  8. dano

    dano Evil Handy Man

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    I bet the ECU ground. My car ran for years then one day no start. Swapped out with one from may dad and the car ran, put my old one on and the car ran. It needs a good solid case to chassis ground.
     
  9. 360Scamp

    360Scamp Mopar or No Car

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    Thanks guys, I sanded real good under where the screws go and I got a new ballast resistor today and when I left the parts store battery was dead! Luckily I had a jumper pack in the trunk because it had been slowly taking a little longer to start and seemed like the battery was getting weak. Once I got it fired up my ALT gauge was showing discharge so I went home and dug out another alternator and its still showing discharge on the gauge. What else could it be causing the discharge?
     
  10. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    1....JUST like the ECU, the regulator MUST be grounded.

    2...Easy check find the green wire at the alternator. Use a "clip lead" and connect the alternator field terminal you just exposed to ground. Start and see if it charges

    If not, measure voltage at (connected) blue field terminal, key on. Should be "same as battery." If so, take your meter, set to "high amps" (10 or 20A scale). Disconnect your clip lead and hook the meter ("on amps) from the alternator field terminal to ground. It should read more than 3A less than 6A. this is field current draw

    3...If that is OK, hook your clip lead back up. If you happen to be in subdued light, you can connect/ disconnect it a couple of times and look for a spark just to be sure

    Now with blue field hooked up "normal" and the other field terminal still clipped to ground, again start and run engine, bring up RPM. CONFIRM voltage is still low, perhaps below 12V

    4...Now move your meter to the alternator output stud. If it was quite low at battery, but way high (over 16V) at the alternator, you have a problem in the "charging line" the wire from the alternator to the battery.

    If both points are still low, below 12 (charging should actually be much higher) then that alternator is bad

    Here's a simplified diagram of the 70/ later charging system. These are INcorrectly called "dual field" They are CORRECTLY named "isolated field

    [​IMG]

    Here is basically what you have

    12V for the field and regulator power is fed directly ( blue) to either field terminal, and to the "I" (Ign) terminal of the VR This "I" terminal is also the "sensing" terminal for the VR

    The "F" VR terminal goes to the remaining alternator field terminal, and controls "the amount of ground" on the field

    Both VR and alternator MUST be grounded MUST

    Output of alternator (factory) meanders through bulkhead terminal, ammeter, welded splice, BACK out bulkhead terminal, and to battery.
     
  11. nm9stheham

    nm9stheham Well-Known Member

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    What ballast brand and PN did you get? Some are right, some are not. The wrong one will cause very weak spark issues.

    The alternator not working could be the alternator (could be 2 bad ones). But more likely a field connection or wire (the small wires on the back of the alternator), the main alternator output (look at where it goes through the firewall), the voltage regulator out, or maybe even the voltage regulator module not being well grounded. It grounds through its case to the chassis just like the ignition ECU module needs a solid ground. Start with the VR ground since you had a bad ECU ground.

    The ignition key feed goes to both the voltage regulator and to the igntion ballast so that is likely OK.

    Do you have a voltmeter? It is very useful for these cars' systems, and gives us pretty good info at times to help figure things out.
     
  12. BillGrissom

    BillGrissom Well-Known Member

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    Refer to the gazillion "alternator - Vreg" threads, w/ responses by 67Dart273. You can "full-field" the alternator by disconnecting both spade terminals and applying 12 V to one and ground the other (doesn't matter which). See if it charges full then. If so, get a multimeter and read what field voltage drop your Vreg is applying to those terminals.

    I assume you have 2 field terminals (1971+), but only because your name Scamp suggest a mid-70's car. Always tell us when asking a question. It sure matters for this question.
     
  13. 360Scamp

    360Scamp Mopar or No Car

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    My car is a 72 with a late 70's 360 out of a motorhome
     
  14. Abodybomber

    Abodybomber Breaking street machines , since 1983.....:) Legendary Member

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    Met Trailbeast in person,driven his car. Seen him talk to Mopar enthusiasts( not me,lol), he knows his sh*t. The best part: the parts in his systems are late model, & readily available anywhere. To me ,that's fantastic. Sure beats sitting on a tow truck, because someone didn't have a MSD,ACCEL or some other aftermarket part not available for a week or "two days away" b.s.....
     
  15. sargentrs

    sargentrs Well-Known Member

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    Most issues I've had with mine have been caused by bad grounding or wiring/connector faults. First thing I do is clean/sand the ground contact between the case and body/frame, then toss the sheet metal screws and use bolts, nuts and star washers. If that doesn't fix it, I start looking and testing for wiring faults like bad terminals or broken/brittle wiring. Bad ground turned out to be my problems with my ignition box, starter relay and VR.
     
  16. tekslk

    tekslk Well-Known Member

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    You can also build your own for a lot less, trailbeast makes a plug and play kit and he also can give you technical support if needed, just pm him.
     
  17. tarvin890

    tarvin890 tarvin890

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    maybe a FSM would help
     
  18. Spunk

    Spunk Well-Known Member

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    Where do you ground the ECU at? I have a ground strap going from the firewall to the engine block but do I need a separate strap for the ECU or just use nuts and bolts? Sorry I am having the same issues with my 69 Dart and thought I would ask the question here.
     
  19. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    The ECU was designed to be grounded via the case and the firewall. In other words the bolts need to be tight, and you need to use star lock washers. THIS IS POOR DESIGN. Yes, I know, "mullions" of these were driven "buillyons" of miles. It is still poor design. You will never ever see anything such as military electronics or NASA, being grounded through the enclosure like these.

    You CAN add a separate ground wire, say, a number 10 jumpered over to the regulator, and to the engine block. But whatever you do, the bolts must be tight and use lock washers.

    If you want to be "fancy" they make a tool to grind paint off around a bolt hole. I admit, LOL, I just scrape around with a screwdriver or knife, etc.
     
  20. BillGrissom

    BillGrissom Well-Known Member

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    I don't see where the OP fixed this. I just re-read and the fact that 2 ECU boxes both quit sparking ~2000 rpm suggests the pickup in the distributor might be the culprit. Check the gap to the reluctor teeth (preferably brass feeler gage). I recall 8 mil, but the closer the better as long as the teeth don't hit. Also, check that the rotor shaft is solid and can't wobble sideways.
     
  21. Spunk

    Spunk Well-Known Member

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    Ok now does the paint just have to be removed around the bolt hole? Or from behind the whole ECU box? Also the star washers do they go in between the box and the screw or between the box and the firewall? If I ground it with the NO 10 where do I attach it to on the ECU box?
     
  22. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Doesn't matter that much. Main thing is that you get some "for sure" electrical conductivity. I've even just scraped around the bolt holes good with a screwdriver. Sand or scrape the rear of the box around the bolt holes. You can put the washers just under the bolts, but they probably work better between the box and the firewall.

    This thing is a poor design. yeh!! LOL. I know they worked, back then, but electrical components should NOT be grounded via the mounting bolts, especially where subject to rust and corrosion.
     
  23. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    Put a ring on the ground wire and attach it right with the ECU mounting bolts and star washer, so the washer edges bite into it as well as the ECU body metal.

    The other end of the ground can be done the same way and mounted anywhere there is a solid attaching point.

    I ground my stuff (like my regulator) to the power brake mount brackets, because that is physically where those types of parts are.
    Anything like that would work well.
     

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  24. mguner

    mguner How many is too many?

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    I know there have been tons of post about the various ignition modules; black, chrome, orange, blue etc. I wish there would be a detailed sticky on the Tech Archive section on this along with the FAQs and solutions. I picked up this 4 pin blue box from an industrial engine supplier that was getting rid of their older Chrysler stuff. Works like a champ.
    [​IMG]
     
  25. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    One problem folks "forget" is that colored boxes (orange, chrome) ONLY applies to OEM, not third party replacements. Even though the orange box was sold "after" it was nonetheless sold through Ma.

    And, third party boxes have become more and more chineseoated over the years. Bill posted some member had a box they took apart, did not even use a "real" transistor like the originals. It had a fake cap on the box, and a smaller transistor inside. This may or may not be good, IE less ratings and poor heat sink
     
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