TBV ignition electronics troubleshooting....

Discussion in 'Electrical Stuff' started by CliffA, Sep 24, 2013.

  1. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    great minds must think alike..:).....i actually did this last night....i used the ohm meter to check the primary and secondary windings of the coil....they were in spec....the primary windings showed .6 ohms and the secondary showed 10,500 ohms.....the spark gap tester i had does not have an adjustable gap so yesterday i bought a new tester that does have an adjustable gap....i set the gap to around 1/4".....i checked the coil wire and had around 286 ohms of resistance so i think the coil wire is OK...then i disconnected all wires to the coil and ran a direct wire from the battery + terminal to the coil + terminal......i inserted the new spark tester into the HT coil wire and clamped the tester to a good ground source (one of the exhaust elbow studs)....then i used a jumper wire to ground the - terminal of the coil.....there was always a good, strong spark on the jumper wire when i touched ground....about every 3rd or 4th time i touched ground with the jumper wire i would get spark from the coil on the tester....the spark was long and thin...it was hard to tell the color of the spark but it looked like it was white....definetly not blue and as i said the spark was very thin.....thinking i may have spark now i hooked everything back up and left the coil wire connected to the tester and the ground source....i turned the key to the 'run' position and used a jumper wire at the slave starter solenoid to crank the engine over as i watched for spark on the tester....there was no spark at the tester as the engine was cranking....not even the thin spark i saw with the coil isolation testing....

    cliff
     
    Last edited: Sep 27, 2013
  2. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    hey Mitch....no, i have not done this test...can you explain how to do it and which grounds i shoud be checking?

    thanks....
    cliff
     
  3. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    Cliff,

    Set the tester gap to 1/8". With the coil isolated, we want it to fire every time you ground the lead. After you have done that, I want you to put the coil back into the circuit and conduct the following test.

    With the key on, I need you to ground the WHT/Green wire intermittently and see whether you get the same spark as you did when it was isolated. Just so you know, we are getting closer to solving this.

    Also, what part numbers are on the distributor pickup and ignition module?

    -JD
     
  4. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    thanks John....i actually did narrow the gap on the tester to around 1/8" or less just to see if i could fatten up the spark.....that did not change things....i still only got a thin spark intermittently when i grounded the - terminal of the coil.....i can never get any spark at all when i ground the green/white wire from the ign module...that is where i always get stuck on the TBV troubleshooting tree....i have verified continuity of the green/white wire from the hall effect sensor to the connector pin at the ign module...

    the part number of the new ignition module is the same as the original module....it is 861253-1......

    the part number for the hall effect sensor is 87-892150Q02.....

    i have two brand new coils i can try on the isolation test if you think it is needed....i tested both new coils connected to the system and still no spark....when i checked the original coil with an ohm meter it tested good so that is the coil i have in the system now...

    cliff
     
    Last edited: Sep 27, 2013
  5. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    Mitch,
    i have done a little research on conducting voltage drop test of a grounding path with a DMM....it looks pretty simple....if i understand it correctly i would just energize the system being checked and attach the - probe from the DMM to the battery ground and use the + probe from the DMM to test the ground connection at the component in the system....anything greater than about .5V showing as the voltage drop could mean a weak or corroded wire or contact point.....does this sound right?....do i simply need to turn the ignition key to the 'run' position to properly energize the ignition system to check the various grounds, includng the main engine block ground to the - battery terminal?

    thanks.....
    cliff
     
  6. techmitch

    techmitch Well-Known Member PLATINUM Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    Sorry for the delayed response time but I have been very busy. I don't like to see any more than .05 Big difference between that and .5 volt. Not sure if you saw this doc. before but see pg. 6 the theory applies to all voltages. http://www.delcoremy.com/Documents/diagnostic-manual.aspx
     
    Last edited: Sep 27, 2013
  7. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    i have not seen this document before...i will look it over....thanks....

    cliff
     
  8. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    for anyone following this thread and interested in learning more about measuring voltage drop here is a link to a short and simple explanation.....it is interesting that a circuit could give a positve result for a voltage test and a continuity test but actually contain a fault that prevents a component from funtioning properly...the only way to detect this type of fault in the circuit is a voltage drop test.....this is probably basic stuff for those well versed in electronics troubleshooting but for an old 'wrench head' like me acquiring knowledge like this, especially on the electronics side, is very interesting....

    http://www.engine-light-help.com/voltage-drop.html
     
    Last edited: Sep 27, 2013
  9. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    Cliff,

    I just read your "just answer" link and it is amusing to see that they are giving you the same advice as I am giving you.

    I know it is frustrating but everything keeps pointing back to the Ignition Module. Your coil is fine. Bypassing the distributor sensor does not fire the coil. That points back to the Ignition Module. You have checked the wiring connecting the Ignition Module and it appears fine. Because it is new and expensive we presume it is ok and keep looking for something else other than the new ignition module to be the issue. There is one last thing I would try before I junked the distributor and the assembly for something else but I need to look at the Ignition Module wire diagram one more time.

    In the meantime, you have multiple distributor choices to consider. I actually prefer marine versions of MSD and Mallory over Delco but it is your choice. MSD and Mallory have integrated ignition module designs, are extremely durable and below $300.

    -JD
     
  10. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    Cliff,

    I know you have been through this test but I need to make sure that you grounded the right lead:


    Remove High-Tension Lead from Distributor to Coil. Insert a Spark Gap Tester from Coil
    Tower to Ground. Disconnect WHT/GRN Lead from Distributor.
    Place Ignition Key in RUN Position.

    Rapidly strike the Terminal of the WHT/GRN Lead that comes from module, against Ground (–).


    IMPORTANT: The WHT/GRN lead must be touched against ground (–) 2-3 times per second to simulate
    a running engine. Repeat this test several times to ensure that spark is present.

    Make sure you are grounding the WHT/GRN lead from the Ignition Module not the Distributor.



    If that test does not work, I would try one last thing before I tossed the whole assembly overboard.

    Disconnect wires #11 (from the back of the tach),5,6 from the Ignition Control Module and make sure #10 has a solid ground. If your ICM has two #5 wires....connect them together. This will eliminate any possible wiring issues and isolate the ICM. Also make sure that the connector and ICM does not have a bent or missing pin. If it doesn't throw a spark isolated from the tach, audio warning and interrupt....it has to be the new ICM.

    One of the reasons that mechanics don't like this system is the cost of the parts. I know you have dropped $350+ on this which is ridiculous when you can buy much better complete units for far less.


    -JD
     
    Last edited: Sep 30, 2013
  11. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
    I`ll post a video of testing them off the boat. how comfortable are you pulling and install a dist?
     
  12. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    thanks John.....I actually tried grounding the green/white wire from the ign module and the green/white wire from the sensor just to make sure I was reading the troubleshooting tree correctly....no spark from either......i will try the test you suggested.....we are going out of town this WE so it will be next week before I get back on this issue.....I just hate admitting defeat.....I will consider changing out the system but only as a last resort.....I may try checking the circuits for voltage drop as Mitch suggested to see if that turns up anything...

    thanks for your input so far.....

    cliff
     
  13. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    It has been a while (a long while) since I pulled a distributor from an engine but I am not afraid to do so.....what are you thinking may show up by bench testing the distributor?

    cliff
     
  14. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    If I do decide to switch to a new ignition system do you know if the MSD and/or the Mallory system is compatible with the shift interrupt circuit on the Alpha drives?......from what little I have read about the Delco system it seems it is compatible with the interrupt circuit where some aftermarket systems are not.....

    cliff
     
  15. techmitch

    techmitch Well-Known Member PLATINUM Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    Don't give up! You can diagnose this! Save your money for fuel.
     
  16. Bob & Sue

    Bob & Sue Active Member

    Jun 3, 2011
    Browns Point Tacoma WA
    Sold 1999 270DA Sundancer
    5.7l Mercuiser
    MSD has a seperate module for the shift interrupt or a ready to run just plug it in distributor, I looked into this when we bought the boat but decided to wait till the TBV fails if it does plus I have a Bravo didn't need shift interrupt. Don't give up now your to close to finding a solution.
    I do have this thread bookmarked for future reference sorry your going through all this.

    http://www.summitracing.com/parts/MSD-4489

    http://www.summitracing.com/search/brand/msd-ignition/department/marine/year/1998
     
    Last edited: Sep 28, 2013
  17. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    My concern is that when Cliff does isolate the ICM, he still won't get a spark which means the new ICM does not work. The really odd part was that he saw a tach signal when he was cranking the engine. Normally when the ICM fails...there is no tach signal and it is a wiring issue (the tach signal "sees" that the pickup and ICM are working correctly). That's why I had him go through every single wire that goes to the ICM and distributor and isolate the components.

    Unless he has missed something, the ICM seems to be the issue. On a two engine boat, it is a simple task to diagnose the actual problem by moving a component from one engine to another. There is never a useful warranty on electrical items so my guess is that he is out the $350 he has already spent.

    If all signs point to the ICM, I wouldn't buy another one. I like and use MSD products.

    -JD
     
  18. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    BTW I just did a search on the part numbers: The ICM (Mercruiser 861253-1) is $350 used on Ebay and $599 new.

    -JD
     
  19. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    thanks for the help and encouragement guys...i am not ready to give up yet....i have a pretty bad case of 'male ego' and don't give up easily on challenges like this....

    i had a lot of time to think about this issue over the W/E while we were traveling....i decided to 'step back' a little and take a look at the issue from a little higher level to determine the next course of testing and what the results would tell me....here is what i am thinking.....

    i believe i have confirmed the hall effect sensor is working properly from the testing i have done....the sensor is reducing the 12V signal down to 4.5V each time a finger of the rotor interrupts the magnetic field of the sensor.....

    the next major player in the ignition system is the control module....i know we have done several test for the module already but there are a couple more i want to do....one test i would like to do is the voltage drop test that Mitch has mentioned....from reviewing the wiring diagrams it looks like the module gets its 'input' 12V power from the purple wire which is wire #5 on the wiring diagram for the module....i want to check the voltage drop from two places to try and confirm the module is either good or bad....i want to check the voltage drop from the + battery terminal to the connector pin for the purple wire as it enters the module...i am thinking to do this i need to connect the + lead from my DMM to the battery + terminal and the - lead from my DMM to the purple wire connector pin and observe the voltage reading as i crank over the engine for a few seconds....anything over .5 volts drop is considered excessive and should be investigated further.....if this test proves OK (less than .5 V drop) i want to check the voltage drop from the + battery terminal to the purple wire supplying power to the coil....for this test i would leave the + lead from the DMM connected to the battery + terminal and connect the - lead from the DMM to the + terminal of the coil...then i would watch the voltage drop as i crank over the engine for a few seconds....if this test passes (less than .5V drop) that would indicate the module and all the connected safety switches and their wiring was OK and i have a problem with the coil or the coil wire....if this test fails (above .5V drop) this would indicate i have a problem with either: 1) the module 2) the throttle kill switch and/or wiring 3) the shift interrupt switch and/or wiring 3) tachometer and/or wiring 4) the alternator and/or wiring 5) the carb electric choke and/or wiring 6) the electric fuel pump and/or wiring 7) the starter solenoid and/or wiring.....i would have to test each individual component and its wiring one at a time to identify the problem or i could bypass them one at a time for testing purposes to see which circuit is bad.....

    can anyone confirm the test methods for the voltage drop at the module connector and the coil i mentioned above are accurate or not?.....does this line of thinkng for the testing seem logical?......


    thanks....
    cliff
     
    Last edited: Sep 30, 2013
  20. CliffA

    CliffA Well-Known Member

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    640 hp (Total)
    Raw Water Cooled
    V-Drive Transmissions
    i was able to find a supposedly 'new' module on ebay for $350.....it did come in the original Mercruiser box and was wrapped in bubble wrap...there were no signs of it ever being installed before (such as scratches at the mounting holes) so i believe it is new.....it is always a gamble when buying 'new' electrical parts from an individual seller on ebay....someone could easily simply repack the defective part they replaced in the box and wrapping the new part came in and advertise the re-wrapped defective part as 'new' in the ebay auction.....

    cliff
     
    Last edited: Sep 30, 2013

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