bad ignition coil?

[tpnotch420]

I pulled both ignition coils to test them because my car doesn't seem to be getting any spark

I checked the voltage coming into both coils with ignition in the on position and got about 11.5 volts on both sides.

Next I checked the primary and secondary on both coils. the results were the same for both
primary was .8 ohms
secondary was 11k ohms

the secondary seems to be with specs but the fsm states the primary should be .4 to .5 ohms

could .3 or.4 ohms be enough to keep my car from starting?

I plan to pickup new coils this weekend

 

[Muzza_NZ]

Unlikely. The higher resistance may just be in the accuracy of your multi-meter. What does your multimeter read when you short the probes together? It's also unlikely that both would fail and give the same readings.

It won't start if it doesn't get the crank signal. If the ecu doesn't see that signal, you might also hear the fuel pump/idle control circuit turn off immediately when you stop cranking instead of running on the extra 2-5 seconds that it would normally do.

Gloverman and Sideshow will have more idea and may chime in with some suggestions.

 

[gloverman]

It would be strange for two coils to fail at the same time. Possible but strange. What vehicle is it? Cheers

 

[tpnotch420]

it's a digital meter and reads zero when I test the 2 leads together. My car is a 92 sc400.

In following procedures in the fsm I tested the coils the cam sensors and the engine speed sensor. all tested with in spec'd tolerance. I also did the spark test and saw no sparks when cranking the engine.

I have another question the fsm refers to an engine speed sensor that is located on the block in front of the oil filter on the driver side of the car, is this also referred to as the crank sensor?

according to the fsm my next point of fault is the ECU is there a easy way for me to test this item before replacing it?

 

[gloverman]

The sensor down by crank pully is the crank sensor (engine speed sensor) , is the ECU getting power? Does the car have an imobiliser? or alarm of any kind? do you know where the main relay is? cheers

 

[tpnotch420]

thanks for the info on the sensor. I found that one and it tested okay per the fsm. My car does not have an after market alarm. It just h as the one from the factory and if I remember correctly when that one trips I get no power at all. The car won't even crank. I found that out the hard way and it about scared the living daylights out of me till I figured out what it was.

today I'm going to put the coils back and test that they are sending spark to the distributor then I will look at the cap and rotor as well as the ecu.

 

[petty]

First test the ignition resistance check as to know if that is caused by a coil's problem. Check this site, this may help you out www.classictruckshop.com/clubs/earlyburbs/projects/trouble/ignition.htm.