checking ignition control

[mikes94q]

ok so I have purchased a fourth ignition control module (transistor ignition unit) from ebay, cant afford the factory prices. I check them per the fsm with a digital ohm reader for continuity and they all comback exactly the same. All four are the same, but none have continuity when they should per the fsm.

Am I doing something wrong or is my luck really that bad on this part? When I test the resistance i get readings around 426. If I go to the Ohm side select 2000 I get a reading of 527. between all four of these I get very similar results, with very little to no difference. Am i doing something wrong? Is there suppose to be power supplied to this to test it?

[Infinitiguy19]

Easier way to test without a Volt Ohm Meter to install it on the vehicle. If it works then all the spark plugs (Cylinders) will be working and producing power on that bank.

[Q45tech]

I've never seen an ignition module on a 90-94 Q45 fail. Lots of harness and connector problems but unless the coil primary shorts there is no way to exceed the transistors disapation rating.

[mikes94q]

q45tech, can you tell me how to check to see if I'm getting the right amount of power at the harness that connects to the module? In my limited experiance, I have never seen this type of part fail, especially have several in had not working. Thanks.

[goody90q45]

Have you tried a different ECU?

[mikes94q]

no I have not tried with another ecu. I guess that may be one of the parts that I order next.

[Q45tech]

Take some time and study transistor theory as you have 8 identical transistors each switching a separate coil.

A dc amplified amp probe with a digital osccilloscope can view the waveforms just as one does with injectors because all are commonly fed from the same 12+ source [wire,relay, fuse].

http://business.shop.ebay.com/Oscillosc ... 247/i.html

[Infinitiguy19]

Hey Mike (Original Poster) talk to this guy: post5695495.html#p5695495

[Q451990]

I remember testing mine a long time ago... maybe 1998? From what I remember everything was exactly backwards from what was stated in the FSM. My dad has years of experience in electronics, and said something about the way the meter tests it can use a couple of different methods, and that apparently the meter they used at the factory was the other type. Of course, it could just be a type-o in the FSM too.

Heath