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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29494
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 1996 chevy cavalier it blew the timing chain

Customer Question

i have a 1996 chevy cavalier it blew the timing chain tensioners and spun the bearing in the lower end so i got a used motor from craigslist which was supposedly the same year but when i changed them the crank sensor in the new motor has a 2 wire sensor and my old motor had a 3 wire i put the old crank sensor in t he new motor and i cant get any fire do i need to use my old icm as well or will the crank sensor not work with this motor looking for a direction to go ...
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam.

Given your system is meant for the old sensor and such, you need to use the old ICM, old Sensor and see then if you get spark. The wiring for the new sensor to new ICM may not be compatible with the old systems.

Can you try this and let me know what you find then reply back?

Customer: replied 1 year ago.
it will take me a while but i will try it so i wont have a compatability issue using the 3 wire crank sensor in the 2 wire sensor engine block?
Expert:  GM Tech (Cam) replied 1 year ago.

The 3rd wire is usually a ground shield wire. Try it and see then reply back to me.

Expert:  GM Tech (Cam) replied 1 year ago.

Please bookmark this page so you can easily navigate back to it so we can continue the discussion. This is done by pressing (CTRL D on PC and CMD D on Mac). You can reply at any time for follow up information regarding this issue, even after you rate the site and I will reply.

Customer: replied 1 year ago.
ok i tried the old icm still no spark where do i go next?
Expert:  GM Tech (Cam) replied 1 year ago.

At your ICM, do you have power on the pink wire and ground on the black?

Customer: replied 1 year ago.
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, the wiring to the crank sensor, what is the resistance over the 2 pins?

Customer: replied 1 year ago.
it has 3 wires...
Customer: replied 1 year ago.
1 is a hot wire 1 is a ground and i thought the 3rd was a signal wire but you said it was obsolete...
Expert:  GM Tech (Cam) replied 1 year ago.

Ground shield its the third, so it should have resistance over the outside 2 wires.

Customer: replied 1 year ago.
i will have to check tommorow and get back to you its getting dark gonna call it a night
Expert:  GM Tech (Cam) replied 1 year ago.

ok

Customer: replied 1 year ago.
do you want me to check the sensor or the harness to the car?
Expert:  GM Tech (Cam) replied 1 year ago.

Both.

Customer: replied 1 year ago.
check it on ohms on the multi meter correct?
Expert:  GM Tech (Cam) replied 1 year ago.

Correct.

Customer: replied 1 year ago.
ok so i don't have anything as far as resistance on ohm meter at the sensor or at the harness i have found out that the motor is from a different system than what the car has hence the 3 wire vs 2 wire crank sensor also at the icm plug car only has 2 wires not six
Expert:  GM Tech (Cam) replied 1 year ago.

Yes, but did you transfer all the wiring harnesses, sensors and modules from the old engine to this one?

Customer: replied 1 year ago.
not the computer or main wireing harness i used the old crank sensor and icm and of course the existing harness is from the old set up
Customer: replied 1 year ago.
can i just use the new 2 wire sensor and the ground and signal wire spliced into the old harness for the crank sensor?
Customer: replied 1 year ago.
from what i understand the old 3 wire requires voltage to work but the new 2 wire does not so can i just omit the hot wire?
Expert:  GM Tech (Cam) replied 1 year ago.

You need ALL WIRING, COMPUTER AND SENSORS from the original engine to make it work.

Customer: replied 1 year ago.
ok gonna go get all the other stuff ill get back to you when i do
Expert:  GM Tech (Cam) replied 1 year ago.

ok

It troubling when parts are mixed up, wiring may not match, computer systems different. Change them out and let me know what you find.