Need electrical help- no spark., HHHHHHHELP! |
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Need electrical help- no spark., HHHHHHHELP! |
tornik550 |
Aug 20 2016, 01:56 PM
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#1
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
I built a /6 2.7 this past winter. I originally ran the engine on a test stand so I could work out all of the bugs. The engine ran great. I had a fairly simple electrical setup and I did not hook up my alternator. Since everything was workin well, I installed the engine in my 914. Once hooked up, I started the car and it ran great for a few minutes than I had to turn it off for unrelated reasons. A week later, I tried to start it up again and everything worked great. Then a couple of days ago, I tried to start the car and after the engine would crank awhile, you could occasionally hear a cylinder fire but the engine never started. Since then, I have not been able to get the engine to start or even any signs of spark.
To check for spark, I hooked up a plug wire to an old spark plug, layer it on the engine, cranked it and looked for spark. I have a msd blaster 2 coil, pertronix ignition, new distributor cap and rotor, new clewett wires. Here is what I have tried- none has worked- I tried the above test with each of the listed changes. -I have tried three different pertronix ignitors (two brand new) -tried three difference could- Bosch blue, msd blaster 2, accel super stock (none of the three are new- I thought they work ok however?) -I tried a new set of points (I did get one spark 1 time) -I have an msd 6al- no luck -battery has 12.8v I even tried rewiring everything as though it was on the test stand. Nothing was hooked up to the car- everything was directly to a separate battery -12v to starter -switched 12v to starter -pertronix + wire to + post on coil, - wire to - post -switched 12v to +post on coil -ground to -coil post That is all that was hooked up and still no spark!!! Spark plugs are brand new also. I just don't get it- I have mega simplified the system- everything worked fine and now nothing. I don't even car if the engine doesn't fire- as long as I am getting a spark, I can work from there. |
stugray |
Aug 20 2016, 02:08 PM
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#2
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
A couple things jump out at me:
-I have an msd 6al- no luck ... -12v to starter -switched 12v to starter -pertronix + wire to + post on coil, - wire to - post -switched 12v to +post on coil With the 6AL you should NOT have the switched +12V OR the Pertronix to the coil +. ONLY the wire from the 6AL. Move the switched +12V for the pertronix OFF of the coil and try again. I have an isolated +12V terminal board on the rear firewall for this connection. The pertronix needs +12V and Rtn to be completely isolated from the coil. With the 6AL, the pertronix does not fire the coil, it only sends the signal to the MSD and IT fires the coil with only the two wires. Switched +12V (IGN) to Pertronix +12V (AND to MSD switched input) MSD needs a separate (non switched) +12VDC straight to battery. Pertronix 12VDC return to chassis Pertronix "firing wire" (normally goes to coil) to MSD trigger input. ONLY TWO wires are to be connected to the coil, and they come from the MSD. |
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