3.1 crankshaft .sensor ?

Asked by Jan 17, 2010 at 10:58 PM about the 1990 Oldsmobile Cutlass Supreme 4 Dr SL Sedan

Question type: Maintenance & Repair

It's a 90 model won't start no fire. Anyway i won't to replace the crank sensor, I was reading that it was at the rear of the motor close to oilpan, is this correct?  I put one on my moms that has the 3800 seris motor, it was behind the balancer. If so how hard are these to replace moms was pretty tuff for me anyway

7 Answers


the location of crankshaft sensor is correct as stated on many sites and according to AutoZone.com under component location it states "Under hood, center, rear engine area, passenger side of exhaust pipe, above oil pan, mounted in engine block" this link may or may not work here it is to try http://www.autozone.com/autozone/repairinfo/componentlocations/componentLocationMain.jsp?categoryNValue=4294963514&categoryName=Crankshaft+Position+Sensor# I have never done it myself, but here is a link to someone that has done it on a similar sister car that you have 1990 Chevrolet Lumina 3.1L http://wiki.answers.com/Q/How_do_you_find_and_replace_the_crankshaft_sensor_on_a_1990_Chevy_Lumina_3.1_Without_having_to_pull_off_the_wheel_spray_guard hopefully this helps

2 people found this helpful.

My son has a 1990 Cutlass Supreme too and it won't fire either. We replace the crankshaft sensor, which was tight to get to, but not difficult to replace. The bad part is, it didn't help. The car still won't fire!! We have tried almost everything including fuel pump, fuel filter, checked spark plugs and everything. The only thing we can think of is the computer board itself. Hopefully that will work, otherwise, it will be a junkyard car!!!

5 people found this helpful.

There is a fuse for the ECM under the glove box, check that.

1 people found this helpful.

Be sure to check the ignition module -the coils are mounted to the module...if sensor was not the issue and the car will fire up and drive until hot then refuse to re-fire until cooled down and it isn't sensor ,most likely culprit is the ignition module.

1 people found this helpful.

a quick additional note -sorry ---also be sure to check that you have voltage at the connector that plugs into the crank sensor from the wiring harness--they are known to go bad..and a replacement can be had at autozone --maybe elsewhere as well-- for 14.99---otherwise i would strongly suspect the ignition module until i ruled it out..--good luck.

1 people found this helpful.

Have you checked for 12 volts from the ignition switch to coils? Also check for good ground to icm. Disconnect two wire harness on passenger side of car, put your red lead of your meter on the pink or pink with black stripe wire. Hook up black meter lead to negative side of battery, turn key on. Should see 12 volts. If have you have 12 volts, Connect meter's black lead to black wire in harness, key off, and then connect red meter lead to positive side of battery. Have 12 volts, ignition switch good. Icm is getting proper voltage. If still no start, then verify that all the spark plugs are receiving no spark. More than likely icm is bad. Note: What I am trying to do is: Just don't start replacing parts, do a little troubleshooting first. The 3x or 7x crank sensor should have an ac voltage output.. The multimeter's AC reading should fluctuate from .3 V AC to 1.0 V AC continuously as the engine is cranking (the maximum AC voltage attained will depend on the temperature of the engine, oil viscosity and battery charge condition). You can check this easily with a multmeter set on ac voltage. Just disconnect the two wire connector on the driver side that is connected to the icm. There is a yellow, and purple wire in this connector. Does not matter which lead of the meter goes to which wire. Also if you get the proper ac voltage, it does not mean the sensor is good. You have to verify the sensor has the proper resistance too. Set your meter to ohms, connect your leads across the sensor wires. If the sensor is working properly, you should see a resistance value between 500 to 900 ohms. Before you replace the sensor, remove and check the wires going to the sensor. There clips that hold the wiring harness away from the exhaust manifold. Sometimes these clips break, and the wire harness touches the manifold and the wires get burnt. This interference with the proper signal to the computer, to adjust the timing of the vehicle. Make sure key is off. A quick test to verify if your getting fuel to the engine, is to find a spot you can disconnect something in the induction hose, and spray starting fluid into it. If car starts, then fuel system is problem. Could be pump, relay, computer wire, fuse. You can always jumper power to the fuel pump from the battery to the pump, or at the relay. From certified mechanic for almost 30 years.

3 people found this helpful.

Ign module or ignition coils I watched a video on Youtube that shows how to test the module and coils and signs it helped me figure it out bought the coils today gonna install in the early morning. Oh yeah check all the plug wires and other harnesses near the fans they tend to come loose and get damaged by the electric cooling fans , it's tight under there but the rewards of kicking that 3,1 to the floor and takin off is so worth the tightness

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