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  1. #1
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    Default Thunderbolt IV ignition questions and timing

    Hey guys, I searched around and now have some questions.

    I posted earlier about my boat suddenly not having any power. I'm fairly certian it is ignition related now. So after reading about the TBIV igntion system...

    -The TBIV Module controls timing right? Are there weights and springs in the bottom of the distributor?
    -I read there's a flow chart for ign system testing, where might I find that?
    -Is there a way to test the TBIV module?


    on a 1994 454 330, what is base timing? What is full advance, and by what RPM should it reach full advance?
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  2. #2
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Thunderbolt IV ignition questions and timing

    -The TBIV Module controls timing right? Are there weights and springs in the bottom of the distributor?
    No weights or springs, all electronic. The module does the advance.

    -I read there's a flow chart for ign system testing, where might I find that?
    There is a chart, but it's only for no spark.

    -Is there a way to test the TBIV module?
    Not that I am aware of.

    on a 1994 454 330, what is base timing? What is full advance, and by what RPM should it reach full advance?
    Identification Mark on module: V8-24
    Module Advance: 24 Degrees
    Initial Timing: 8 Degrees BTDC
    Total Advance: 32 Degrees
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  3. #3
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    Default Re: Thunderbolt IV ignition questions and timing

    Thanks so much!
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  4. #4
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    Default Re: Thunderbolt IV ignition questions and timing

    Is it possible for the advance side of the module to go out? Has anyone ever heard of that happening?

    Also, I can't even see my timing marker from the top, do you sometimes have to pull the power steering pump off to time the engine?
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  5. #5
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Thunderbolt IV ignition questions and timing

    If the advance doesn't work, about the only thing it can be is the module or the wiring and connections. Nothing in the distributor to cause it.

    As far as seeing timing marks, you just have to do what's needed to see them.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  6. #6
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    Default Re: Thunderbolt IV ignition questions and timing

    Quote Originally Posted by Don S View Post
    If the advance doesn't work, about the only thing it can be is the module or the wiring and connections. Nothing in the distributor to cause it.

    right, I just wanted to verify that it's possible for the module to work enough for the engine to start up and idle, but not advance so the engine wouldn't have any power under load.

    Thanks again.
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  7. #7
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Thunderbolt IV ignition questions and timing

    Have you actually ran the engine to see if the timing is advancing or not. You don't have to be in the water, it works on rpm of the engine.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  8. #8
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    Default Re: Thunderbolt IV ignition questions and timing

    no, that's what I'm doing tonight...Thats why I asked about removing the p/s pump in order to see the marker. ha, I'm just...preparing. Making sure the i' are dotted and t's are crossed.
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  9. #9
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    Default Re: Thunderbolt IV ignition questions and timing

    Okay, I checked timing. It was waaaay off. Very advanced at idle. I moved it back to around 8 degrees BTDC and the idle adjust properly, sounds alot better now. The mark was bouncing around a little at idle but not bad. Then I increased throttle and the timing mark moved. I put the dial around 30 degrees on the timing light, and that seemed to bring it right around top dead center. It bounced some here too, but it was hard to keep throttle steady (I took the cable loose to move throttle by hand) and watch the mark at the same time, so that could account for some of that. So it seems as if that is functioning as it should.



    SO...could timing off that much be the cause of no power?
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

  10. #10
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Thunderbolt IV ignition questions and timing

    SO...could timing off that much be the cause of no power?
    Absolutely.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  11. #11
    Petty Officer 2nd Class
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    Default Re: Thunderbolt IV ignition questions and timing

    How did your timing change?

  12. #12
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    Default Re: Thunderbolt IV ignition questions and timing

    well, there's 2 separate issues here...maybe.

    The back story is we were out on the lake, and then all of a sudden it didn't have any power. Would start and run no problem, but you could hold it to wide open and it'd have no power, and wouldn't go over 3000. I thought it was intake gaskets, so I marked the distributor, pulled intake, and put the dizzy back in where I pulled it. SO...timing could be off because I didn't put the dizzy back in right. However, when I took the boat out after the intake gasket change, it had the exact same characteristics as before. So, my thinking is the distributor clamp was loose, and as we were balls out on the lake, it was slowly turning until it reached the point that the module couldn't compensate anymore.

    I can't see any other problems with the ignition system or fuel system, so I'm going to have to take it out on the water to find out. Bring my vacuum gauge and the timing light and try to diagnose more if that, indeed, wasn't the problem.
    Currently: 1994 VIP Vindcator 23' 454 with Mods, BR1

    1973 Taylor SS 19' Jet, 496 Stroker, Berkley Pump, Hydraulic Place Diverter - WANNA BUY IT?!

    1973 cobalt tri-hull. 140 mercuiser. pre-alpha. SOLD

    1985 SleekCraft Ambassador 26' Volvo AQ290A and 290 drive. SOLD

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