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Thread: MSD 6AL-2 programmable - no spark at spark plugs.

  1. #1

    Default MSD 6AL-2 programmable - no spark at spark plugs.

    Hi all. I have a small block Chevy with an MSD 6AL-2 programmable box, Pro Billet 85551 distributor and Blaster SS coil, new cap & rotor.
    The problem I'm having is that I'm not getting any spark to the park plugs. I have done the coil spark test and all is good there (can still feel the belt I got, LOL). I've done the magnetic pickup Ohms check and have .536 Ohms, checked pickup with continuity test with plenty of beeps and distributor also made a small voltage when spinning shaft. I've checked the voltage to both red cables going into the box and have full 12 volts, earth is going straight to the battery with terminals cleaned with emery, checked earths (engine to chassis, engine to battery, battery to chassis) with multimeter all with 0 ohms resistance (Checks done at various different places not just at earth points).
    I have the distributor pulled out of the engine at this point to allow me to turn the shaft to simulate engine cranking, and eliminates any sort of voltage drop, and have a spark plug earthed to the engine to check for spark.
    I do get a single weak spark straight after I turn ignition on, but only one and then nothing.
    I did remove the CDI box to bench test, which all came back fine again. So hooked up distributor to MSD (again not installed in the engine) and had good quality spark at the plug, so installed distributor and car started. Tuned everything up and turned engine off. Probably had engine running for 30 minutes.
    Next day went to start engine again and no spark again. So at this point I'm getting very frustrated and I'm ready to scrap this bloody MSD setup.
    The only things I haven't replaced is the magnetic pickup and reluctor wheel, but again all tests show that they seem to be good. Even checked air gap in distributor and have .022", all within spec.

    Sorry for the long winded post, just trying to provide as much info as I can, and I'm hoping that someone here has experienced the same thing and can say, "Hey, try this".

  2. #2

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    So on the small red wire going from the box to the key switch, how many volts are you getting WHILE CRANKING?
    shake-n-bake

  3. #3
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    If you have 536 Ohms across the pickup, what do have looking back towards the distributor pickup from the connector at the module end, while this no spark occurs? So this will measure the pickup and the harness as a loop test, which including the male/female connector. Gary
    Regards, Gary

  4. #4

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    Quote Originally Posted by msdtech50 View Post
    So on the small red wire going from the box to the key switch, how many volts are you getting WHILE CRANKING?
    I have the distributor out of the engine at present doing my tests, so have full 12 volts at the small red wire while turning the distributor.

    Quote Originally Posted by Gaz64 View Post
    If you have 536 Ohms across the pickup, what do have looking back towards the distributor pickup from the connector at the module end, while this no spark occurs? So this will measure the pickup and the harness as a loop test, which including the male/female connector. Gary
    Gary, do you mean test the resistance at the plug of the green/purple wires going to the distributor from the box or check the voltage? Sorry, I'm not quite sure what you're getting at. Corey

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    Hi Corey. If you know the pickup measures 536 Ohms, I'd like to know if the "loop" including the 6 feet of two wire harness is also 536 Ohms, which will prove the connector near the distributor. Gary
    Regards, Gary

  6. #6

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    Hi Gary. I've checked the loom and it was .571, rechecked the distributor and had the same reading. So my reading of .536 must have been .563 with my dyslexia, but still within spec.

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    Quote Originally Posted by msdtech50 View Post
    So on the small red wire going from the box to the key switch, how many volts are you getting WHILE CRANKING?
    This is a VERY IMPORTANT test.

    Quote Originally Posted by corey lanctot View Post
    Hi Gary. I've checked the loom and it was .571, rechecked the distributor and had the same reading. So my reading of .536 must have been .563 with my dyslexia, but still within spec.
    I'd say your loop is fine. Gary
    Regards, Gary

  8. #8

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    Quote Originally Posted by Gaz64 View Post
    This is a VERY IMPORTANT test.
    As I currently have the distributor out of the engine, I've done this test with only with the ignition on, which has a full 12 volts, so therefore should have full power while I'm turning the distributor shaft. I've even checked with that small red wire going straight to the battery with the same results. I'm wondering if the magnetic pickup is failing, as I had no spark, then it decided to work, and now has no spark again. All tests for me are leading to the distributor, which only has one part that appears to test OK, which is very frustrating. It's going to cost me the same amount to get the distributor bench tested, as it is to buy a new one, and I don't want to keep throwing needless money at this thing.

  9. #9
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    So try replacing the magnetic pickup in the distributor.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  10. #10
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    Quote Originally Posted by corey lanctot View Post
    As I currently have the distributor out of the engine, I've done this test with only with the ignition on, which has a full 12 volts, so therefore should have full power while I'm turning the distributor shaft. I've even checked with that small red wire going straight to the battery with the same results. I'm wondering if the magnetic pickup is failing, as I had no spark, then it decided to work, and now has no spark again. All tests for me are leading to the distributor, which only has one part that appears to test OK, which is very frustrating. It's going to cost me the same amount to get the distributor bench tested, as it is to buy a new one, and I don't want to keep throwing needless money at this thing.
    Make sure there is no metallic buildup on the front face of the pickup. If the "Paper clip" jumper test is reliable, but spinning the distributor isn't, replace the pickup assembly. Gary
    Regards, Gary

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