Exactly what does it do?

My car is hard/imposs. to start some times and if I add some fuel in the air filter it fires up and runs fine. Could the Ign.mod. be damaged?

Ive heard that it "controls the fuel" under 400 rpms



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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTB, ported plenum, 52 TB, MSD 6AL, TPIS level V prom, Mod .MAF, Superior shift-kit and some minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

 

The ECM controls the fuel. I'd get a "noid" light and plug it into one of the injectors. See if the ECM fires the injectors while you're cranking by watching that light. I'm sure there's gonna be a lot more things for you to try in the following posts

 

I don't think it's the module either. The spark module reads the magnetic pulses sent to it by the pick-up coil (also in the distributor). The pulses signify when each cylinder is supposed to fire.

The module than sends this info to the ECM. The ECM then tells the module when to trigger the spark coil (computer-controlled timing) to send a spark to the plugs.

So if you're adding fuel to start the car, if you had a bad ignition module, you'd have a weak-to-none spark, and extra fuel wouldn't help.

Now, a module usually goes bad when the car's nice and hot- it won't supply a strong (or any) spark. When the car cools down again, the module starts to work. Does this happen to you?


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TomP, good thinking, but we can't always assume when it comes to automotive electronics. Yes, when the ignition module goes bad, you would think that you would loose spark, but the Ignition Module is responsible for interpreting the pickup coil into an RPM signal that the ECM uses for injector firing.

Yes, the module controls sparke below 450 RPMs, and My friend has the same problem. When the car won't start, he sprays some ether and it fires right up and runs great. I think that when the module switches to ECM spark control, the module starts to send the RPM signal, it just needs to get past 450 RPM (thats why it runs after the "boost" but not just normal cranking, since cranking speed usually is below 450 RPM)

I would replace the module and see what it does. There are cheap and easy (don't we wish everything was [use your imagination])

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Yes, your ignition module is bad. I'll bet a weeks check that if you were to put a test light accross any of the injectors that you won't have any pulsing light like it should. The ECM tells the injectors to pulse but needs the referance from the module while cranking(under 400rpm) to the ECM so it then pulses the injectors.
It starts after you put a little fuel in because after 400rpm the ECM doesn't need the referance from the module, it goes straight into run mode and pulses the injectors by itself.



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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup, Dual IROC Fans.

http://www.sethirdgen.org/octride.htm

 

GMTech,
You beat me to it by 5 minuntes!

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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup, Dual IROC Fans.

http://www.sethirdgen.org/octride.htm

 

Thanks guys!

I'll buy a new one.

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTB, ported plenum, 52 TB, MSD 6AL, TPIS level V prom, Mod .MAF, Superior shift-kit and some minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)