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| No start / No spark troubleshooting (Page 2/2) |
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Duck Hunter 117
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JAN 23, 02:01 PM
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| quote | Originally posted by Whuffo:
No voltage on either wire: bad fusible link.
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I am having this problem with my 88GT but it will start after being hooked up to a battery charger for ~10min. The battery is good, had it tested. What is the "fusible link" I should be looking for?
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americasfuture2k
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JAN 23, 06:28 PM
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86GT3.4DOHC
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JAN 24, 09:17 AM
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The DIS system is fundamentally the same, but a little simpler.
The Crank Posistion Sensor (CPS) has replaced the PUC, but still acts the same and performs the same functions.
To test a CPS, just check for AC voltage between the two pins while cranking. Voltage means its good, flatline means its bad. Its signalling right off of castings on the crank, so theres no 2 ways about it (other than bad wiring)
The DIS module (ICM) is very simple. Just feed it 12v, ground, and CPS signal and it will spark.
So confirm you have 12v and ground to it, confirm the CPS is outputting AC voltage, and take all the plug wires off and crank. You should be able to watch the spark jump from tower to tower in sequence. If any one coil isnt firing, its painfully obvious. If none of them are firing, I would take the module in to be tested and plan on buying a new one.
As far as the car only starting on battery charger, Im gonna go with the battery has to be bad, or you have a bad connection that is being remedied by the charger. If you had a blown fusable link, then its blown, and theres no way for it to ever work again until its replaced. And think about it, all you are doing with the battery charger is forcing more power into the battery, thats not going to effect anything else.
So, its either got to be the battery doesnt have the power to crank the engine, or there is a bad connection and the battery doesnt have the power to overcome the resistance AND crank the engine under its own power. OR you are changing something, wiggling something, when you connect the charger.
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Duck Hunter 117
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JAN 24, 02:52 PM
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I have a brand new ICM in the car, so I know that portion is good. Is there a way to test the 4-pin connector that attaches to the ICM to read the voltages with the ignition on? To make sure the ICM is getting power?
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MacDee
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JUL 23, 03:09 PM
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| quote | Originally posted by Whuffo:
If your Fiero was running good but now it won't start - watch the tach as you crank the engine. If you see the needle bouncing as the engine cranks, the ignition system is working. But if the tach just lies there at zero - here's how you figure out what the problem really is. It'll take a few minutes - but it'll save you time and dollars in the long run. Many good parts get replaced chasing Fiero ignition problems.
You need a voltmeter or test light; connect the negative lead to ground. Now, gently remove the two pin connector from the side of the distributor and measure the voltage on both pins in that connector with the ignition ON. Also, wiggle the wires as you're measuring the voltage.
Results:
Solid 12 volts on both wires: bad ignition module.
Solid 12 volts on only one wire (the pink one): bad coil.
No voltage on either wire: bad fusible link.
If the voltage varies as the wires are moved, the cable between the distributor and coil is bad.
That little 2 wire cable from the distributor to the coil is a known trouble source. The wires break where they bend coming out of the connectors; when they do it usually results in an intermittent connection. What happens far too often: wire in that cable breaks, car dies. Owner says "ignition module" or "coil" and replaces the suspect part. While doing this, they move the bad cable and the wires make contact. Car starts; it's a successful repair. Nope - they just replaced a good module or coil. In a little while they'll do it again.
Save your money and avoid an unreliable car - use this simple procedure to pinpoint the failure. |
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Done all of the above. Ignition coil checks out. Puc checked out too but replaced anyways. New Distributor and rotor. Tach bounces when turning over but no spark. Both wires or the two wire connectors show full voltage so I replaced ICM three times, one from Napa, one from O'Reilly's and last one an AC Delco GM from Advance all show the full voltage on both wires . What are the odds that all three were bad out of box? When I asked if the parts store if they can check an ICM they all looked at me like I had three heads and they didn't know what I was talking about! I've combed the forum and net for things to try. I'm stumped. Anyone know a place that'll check an ICM before I buy it?
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