No Coil Output

Discussion in 'Injection Tech' started by JoeHall, Jan 9, 2020.


  1. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    Have been driving the 63 Studebaker Hawk mostly for the last couple of months. After letting the other (62) Hawk sit for maybe a month, attempted to start it today, but no go. I have learned to watch the electric tach while the motor is cranking, to determine if the coil is firing. Today, the tach is not moving, so it looks like an ignition problem. Since I know the coil is not firing, pretty sure fuel is not spraying from the injectors either, but will check anyway. Also, will pop the distributor cap for a peek. Then I will focus on the ICM, since that has been the problem the 2-3 times this has occurred before. Once, the epoxy had let go in the magnetic pickup inside the distributor, but it's usually the ICM. I have also learned to use Delco parts whenever something needs replaced. Long ago, I grounded the ICM to the motor and to the firewall, so it's not grounding that causes them to fail. I have heard the ICM is the weakest link in the bullet proof GM ignition. Will post later to tell what the problem is, but gonna start with the ICM. Glad I have a spare ICM on hand.

    Not complaining, as I have had HFI in this car since 2012 and about 40,000 miles. Need to stop letting them set so long. Between three Studebakers and a GoldWing, just too many toys I guess. Retirement is wonderful though, and now they are, "pleasure" vehicles instead of work vehicles. LOL
     
    Last edited: Jan 9, 2020
  2. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    Well that did not go as hoped. First, I looked inside the dizzy for anything obvious. Next, swapped the ICU with a known good spare, to no avail. Next, swapped the coil with a known good spare, to no avail. Out of quick fix ideas, I next reviewed troubleshooting in the HFI Manual. Per the manual, I double-checked wiring and fuses; power to the injectors (present with key one and when cranking); power to the small pink wire when ignition on and when cranking; power to the positive coil terminal; there is voltage to the CEL with the key on, and battery voltage (12.4). I split the siamesed relays that are by the ECU and can feel them both working (FP relay and unknown relay).

    The symptoms I found are related to both ignition and fuel: Though it has power, the CEL does not come on at anytime. Neither the coil wire nor plug wires will light the timing light when the motor is cranked. As always, the fuel pump comes on when ignition is first turned on, and kick off in 2-3 seconds at 12 PSI, as indicated on the permanently mounted FP gauge. But the gauge drops to zero when the starter is engaged. So it is not getting fuel or spark. Needless to say, no spray from the injector nozzles, and the tach needle does not move when cranking, as it should.

    The HFI troubleshooting instruction mention the dizzy magnetic pickup, since it triggers the coil and injectors. It also mentions the ECU. I have a spare magnetic pickup to swap in, but is there any use if the CEL does not come on? Other than that, I am out of ideas.

    Hopefully Bill, or some other guru will offer some insight, but I am about of ideas.
     
    Last edited: Jan 9, 2020
  3. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

    Joined:
    Dec 25, 2002
    Messages:
    17,102
    Likes Received:
    273
    Trophy Points:
    83
    Location:
    Whidbey Island, WA
    If you don't have spark, you won't have fuel.
    There are only 3 parts to spark.
    Pickup
    Module
    coil
    All 3 can be tested.
    Pickup- use an ohm meter and measure the resistance between the P and N terminals of the distr.
    200-400 ohms
    make sure the air gap is set to .008(closest it can get without touching)

    Coil- ohm meter, + to - is .7 ohms
    + to middle ~ 8K ohms
    12v on + and - side with key on.

    Module- take to parts store and have them test it 3 times.
    If it fails, replace.
    If you replace, have them test the new one before leaving the store.


    NOTE: I never mentioned the ECM. It has nothing to do with spark.
     
  4. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    Thanks Bill, Since I have replaced the ICU and coils already, I will next replace the pickup. If need be, I can swap them all three out again, with those on the 63 Studebaker, which is running perfect.
    QUESTION: Is there any relation to the fact that the CEL has power, but does not come on?
    Thanks
     
  5. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    FIXED IT! I checked ohms at the ICU end and there was no reading. So I then disconnected the extension harness near the dizzy, and found 320 ohms.. I reconnected the harness, and then fund 320 ohms back at the ICU end. I then hit the key and the motor fired right up. So apparently, it was a bad P&N wire connection down at the dizzy.
    Whew, what a relief! Just sorry it took several hours to find, since I was planning on washing the car and going for a drive in today's unseasonably warm weather. Supposed to pour rain tonight and tomorrow, so I will wait for a better day.

    I still do not have a CEL, but perhaps it had been out for awhile and I just never noticed it. I highly doubt that, but suppose it's possible. Will work on it later.

    Thanks Much Bill. I dunno what we'd all do around here if it weren't for you!
     
    scout2000 likes this.
  6. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

    Joined:
    Dec 25, 2002
    Messages:
    17,102
    Likes Received:
    273
    Trophy Points:
    83
    Location:
    Whidbey Island, WA
    You're still ASSUMING too much.
    First, I never just swap parts to trouble shoot.
    You do not know if the "new" part is good.
    Second, the SES light always has 12v on it.
    The ECM controls grounds not voltage.
    So it only comes on when gnd is applied by the ECM.

    You didn't get a light because there was no faults within the monitored sensors.
    fuel pump, hoses, wiring, distr... are not monitored by the ECM.
    Just the results of what they provide. fuel and spark.
    If it don't start, you lost one of them.
     
    JoeHall likes this.
  7. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    No rain today, so I planned to drive the 62GT but, again, no start. So I first checked pickup wire ohms at the P/N end, where it connects to the ICU, and got no reading. So I disconnected the extension harness at the distributor and checked again, 320 ohms there. So I took the harness inside and checked for continuity, end to end. It was OK, so I trimmed excess rubber off one end, then crimped both ends slightly for a tighter fit. I then reinstalled the harness and the car fired right up, so I went for a 50 mile drive, and no problems. Pretty sure it was the harness connectors at this point, but plan to start the car everyday this week, just to be sure.

    As for the CEL, the HFI Manual's troubleshooting procedures tell how to check it on page 24, section 12. As mentioned, it has voltage but no light. To be sure, I also checked the CEL on the other car and it comes on with the key, but goes off when the engine starts, as I remember this car doing. So I have ordered a new CEL online, and hope the bulb simply blew.
    Thanks Again Bill, for all the help!
     
    Last edited: Jan 10, 2020
  8. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

    Joined:
    Dec 25, 2002
    Messages:
    17,102
    Likes Received:
    273
    Trophy Points:
    83
    Location:
    Whidbey Island, WA
    You should always get light on, blink once then stay on when you first turn the key on.
    A simple 12v test light can be used to verify the operation.
    We were talking about no start problems so i did not separate the 2 things you mentioned.
    I thought you were asking why no error code/light for the no start.
    Not no light at all.
     
    JoeHall likes this.
  9. JoeHall

    JoeHall Farmall Cub

    Joined:
    Apr 28, 2012
    Messages:
    38
    Likes Received:
    9
    Trophy Points:
    8
    Location:
    Radcliff, KY
    UPDATE: I received the new CEL, installed it, and it works as it should. I have also started the car daily, and driven it a bit over 300 miles in the last week, without anymore problems. Here in Kentucky I love to travel meandering little backroads, and often wind up out in the middle of now where. It takes a bit to build up confidence in the old Studes, after there's been a mysterious problem, such as this was. But confidence has returned, and today I drove around 75 miles on such roads. Life is good. Thanks Again Bill !
     

Share This Page