Electrical Gremlins! No spark on my 5.0L

[crumpledoor#1]

Hmm, just to add insult to injury I have just noticed that the hose coming out of the drivers side fuel rail has totally rotted to the point of hanging on by only a few fibres. Never noticed before as I run on LPG. Looks like it runs through the inlet manifold and connects on the front top of the manifold. Oh well hose is cheap.

Back to the electrical side, going to try replacing the coil first. Fingers crossed thats what it is.

 

[wamboin23]

check things properly before you go blindly replacing things.

do you have pulse to the coil? it's all well and good to have power, but without an earth it's not going to do anything.

if you don't have pulse to the coil, you need to check that you have a pulse from the distributor back to the ignition module, and check for power and earth etc at the ignition module.

if you do have pulse at the coil, replace it.

 

[crumpledoor#1]

check things properly before you go blindly replacing things.

do you have pulse to the coil? it's all well and good to have power, but without an earth it's not going to do anything.

if you don't have pulse to the coil, you need to check that you have a pulse from the distributor back to the ignition module, and check for power and earth etc at the ignition module.

if you do have pulse at the coil, replace it.

How do I check the pulse on the coil? Do I hook up my led light to both terminals on the coil i.e. one wire to one terminal, the other wire to the other terminal? Then turn over the engine to see if there is a spark?

Which wires on the ignition module do I check?

 

[Cheap6]

Between the module and coil, you can check the wires first - that they have continuity using an Ohmmeter or, with them disconnected, that they'll conduct when connected to power and earth using a test light.

Three of the wires from the distributor to the module are for the Hall sensor. One should be battery Voltage with the ignition on, one earth, one switching between 5V and earth as the engine is rotated. (I don't know the wire colours off the top of my head although I may have posted them previously.) That will check that the CAS (Hall sensor) is working.

The ignition module will earth<->open circuit the earth wire from the coil (the coil should have + and - symbols moulded into the plastic top). I think this is a brown wire (but I'm not certain). It should switch from battery Voltage to earth as the engine is cranked. Depending on your test light, you might see your test light connected between this wire and earth flash as the engine is cranked. If so, the module is good. If not and the CAS signal is present the module is suspect.

The modules can be repaired. If you search online you should be able to find how to pull the module apart and replace the power transistor that usually fails. If you can't find anything I'm sure I have how to do it saved somewhere.

 

[crumpledoor#1]

Between the module and coil, you can check the wires first - that they have continuity using an Ohmmeter or, with them disconnected, that they'll conduct when connected to power and earth using a test light.

Three of the wires from the distributor to the module are for the Hall sensor. One should be battery Voltage with the ignition on, one earth, one switching between 5V and earth as the engine is rotated. (I don't know the wire colours off the top of my head although I may have posted them previously.) That will check that the CAS (Hall sensor) is working.

The ignition module will earth<->open circuit the earth wire from the coil (the coil should have + and - symbols moulded into the plastic top). I think this is a brown wire (but I'm not certain). It should switch from battery Voltage to earth as the engine is cranked. Depending on your test light, you might see your test light connected between this wire and earth flash as the engine is cranked. If so, the module is good. If not and the CAS signal is present the module is suspect.

The modules can be repaired. If you search online you should be able to find how to pull the module apart and replace the power transistor that usually fails. If you can't find anything I'm sure I have how to do it saved somewhere.

Thanks heaps for that. :clap: I have an LED test light and also a multimeter I can use to check these components. Where is the Hall sensor located? Is that inside the distributor? I really hope thats not the problem, I dont want to have to take off the inlet manifold to change dizzy's. Mind you, thats still a better solution to a car sitting in the garage stagnant.

 

[crumpledoor#1]

Hooked up my led light to both terminals for the coil. Coil unplugged from terminals. Cranked over the car and the light stats solid. Guess that means stuffed ignition module. I have injector pulse, so I guess hall sensor is fine.