1979-1993 & 94 Conv [Subscribe to Daily Digest] |
Disclaimer - I only know 7 things - but think I know a lot more. So double check anything you hear from me.
First - with a helper cranking the engine, listen to the fuel pump. If it is running, great. It's probably not. That doesn't mean it's bad - it just means the ECU hasn't turned it on yet.
When you turn on the key, 12V goes to just about every component. The components won't go on though until a relay or circuit establishes a connection to ground.
Crank the engine and the hall sensor should sense that the distributor is spinning. The ignition control module listens for the hall sensing the spinning distributor. The ignition control module then tells the coil to start firing spark. When you have spark and distributor spinning, the ECU grounds the fuel pump relay, opening it and sending power to the fuel pump. Spin, spark, ECU, fuel pump relay, fuel - start.
There are other components in line that all have to start sending info to keep the car running. The AMM, throttle position sensor, apc, knock sensor...and others.
But a no-start or start-and-die can usually be isolated to :
1. Distributor and/or Hall Sensor (on your distributor)
2. Ignition Control Module (front left fenderwell)
3. Coil (above radiator) and then the wires, cap and rotor.
4. ECU
5. Fuel Pump Relay.
On mine - I'm going on 2 weeks with no start (or an ocassional start and die). I'm 75% certain that my hall sensor is bad. Ordered a rebuilt distributor - we'll see if I'm right. The connector to the hall sensor on both of the distributors that I already have, is broken. This leaves the wires to the hall vibrating against the side of the distributor, and eventually they wear through. First the wires that carry signal will ground themselves out to the side of the distributor - intermittent problem. Then they'll break. They are very light gauge wires.
Hall sensor is picking up the signal, but can't send it to the Ig Ctrl Module through broken wires, so the ICM doesn't signal to start spark (I have checked...no spark), so the ECU doesn't ground the fuel pump relay turning on the pump.
Even when I jumper the fuel pump, I still won't start because of no spark.
Clear as mud?
Remember, I only know 7 things.
Double check me on everything.
-Jeff
posted by 207.230.140...
, Tue, 24 Apr 2007 11:09:47
, Tue, 24 Apr 2007 05:01:02, Tue, 24 Apr 2007 09:09:12
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