1G CAS and Power transistor

[BigRb247]

I did a 2.3 swap on my 94 awd. I only get spark in 1&4. I tested 3 power transistors. They all came out to almost the same readings, but they were opposite of what the book said. "there should be continuity when voltage is present and no continuity when voltage is removed. " this of course done with a 1.5V battery. When power was present, the DVOM read OFL on 2&3 and 0.0 ohms on 1&4. and when power was taken away 2&3 had around 47 ohms and 1&4 had some other number, but showed continuity. All 3 transistors tested the same, so are all three bad? or is the book bad?

 

[BigRb247]

I was wondering if anyone could tell me how to test the actually CAS with my DVOM. I know the book shows how to check the harness side, but how do i ohm out the actuall CAS? And what are the specs? Also, i tested 3 power trasistor packs that i have and all of them tested out around the same readings, but opposite of what the book said. when i had 1.5v power to the transister it read 0.0ohms and on 2&3 OFL. And then when i took power away from it, one side read 47 ohms and the other side 22.7 or somthing like that. IS it possible all three are bad? The reason im asking is because i sawped a 6 bolt 2.3 in and theres only spark in 1&4, and no fuel. Did no check if the injectors are pulsing or not. any help would be apreciated. thanks

 

[alexg1323]

sounds more likely to me your multimeter is off rather then everything your testing being off constinstantly. Might want to check with another instrument

 

[ADrewzki]

The way that I did it was to hook up power to the positive and ground. Then slowly rotate the CAS by hand. You'll hook up your positive lead to one pin and the ground lead to the ground on the battery. I can't remember which pins exactly on the CAS. I can go look at it later if it's super important to you. You're expecting +5Vdc when the CAS is working properly.

 

[BigRb247]

yea if you could chekc the pins later and get back to me that would be great. I need to narrow down why im not gettting spark.

 

[ADrewzki]

Hey, sorry it took me a while to post back. Here's a picture I found instead. http://www.magnusmotorsports.com/images/1g2g/wiregram/wiregram01.jpg

The power is pin 3, ground is pin 4. Connect those up to power the cas. Connect your multimeter to pin 1 and ground and rotate by hand. Look for 5Vdc when it triggers. Same with pin 2 and ground. Hope that helps.

 

[steve]

The ECU is providing 5v on pins 1 and 2 via pullup resistors. The CAS then pulls the lines low to form the pulses at the correct times. You should see 5v on those pins from the ECU with the CAS disconnected first to make sure the ECU is pulling them up.

This also means you can't just power the CAS itself for testing without providing the pullups.

Steve

 

[BigRb247]

Alright well pin 1 and 2 both had 5v going to them, pin 3 had around source voltage, and ground was of course 0v. what next? Does pin 3 check out?

 

[steve]

So far you have just established that the CAS is wired correctly and that you have power.
You have to rotate the CAS and watch for pins 1 and 2 toggling between 0v and 5v to tell if the CAS is working. Pin 1 (the TDC signal) should pulse twice per revolution and pin 2 (Cam signal) should pulse four times.

Steve