Crankshaft Sensor Location

[kramer2125]

Alright, so when you twist the key to start the car, the motor chugs and chugs but fire. Autozone tested the coils and ICM (both fine) she has new plugs and wires (less than a week old) I know they're in the right place. So i asked the dealership what they thought. They think its the crank sensor. Is that the sensor thats just above and right of the oil filter. I assume the crank pulley is the one at the bottom in the center. Between the alternator and the power steering pulleys.

Ya'll think its the crank sensor?

[98Camaro3.8]

http://home.cfl.rr.com/mkaprocki/Camaro/L36.bmp

5: Camshaft Position (CMP) Sensor
7: Oil Pressure Sensor

Behind 6: Crankshaft Position (CKP) Sensor

The CKP is behind the crank pulley. You have to remove the pulley to get access to the sensor.

Do you have access to an Autotap?

[kramer2125]

Great diagram. Rockauto has the CKP for $25. If the CKP doesn't fix my problem. I'll autotap it.

[98Camaro3.8]

You'll also need a puller to remove the harmonic balancer, a new Crank bolt, and a torque wrench to tighten the bolt to spec. ;)

[ October 14, 2004, 04:28 PM: Message edited by: 98Camaro3.8 ]

[kramer2125]

Can you buy the bolt alone? Autozone has the puller. Would you buy a craftsman torque wrench for $30?

[98Camaro3.8]

Yes, you can get the bolt from a dealer for like 15 bucks. You probably could reuse the old one, but I'd use a new one just to be on the safe side.

I have 2 torque wrenches now. One of them is a Craftsman and it's nice. Just make sure it goes to 110 ft lbs (plus an additional 76° using a normal wrench).

[HBHRacing]

why not just do the simple things and check for spark and fuel pressure first? if the crank sensor was bad you would not get spark

[C.O.Jones]

Originally posted by HBHRacing:
why not just do the simple things and check for spark and fuel pressure first? if the crank sensor was bad you would not get spark

Untrue. A bad crank sensor would still give you spark, however it would cause the car to shut off intermittantly. (know from personal experience).

http://www.syracuse.com/business/pos...7454151770.xml

A I am no genius, but I do think I know what's going on with the Taurus. The symptoms you describe are classic for an intermittent crankshaft position sensor. The sensor often becomes intermittent, particularly when it gets hot.

The SHO engine has two engine position sensors: a camshaft position sensor and a crankshaft position sensor. Although either can fail, only a faulty crankshaft position sensor can cause the engine to shut down once it's running.

This is because the proper coil firing sequence is established when the engine is first started, using the camshaft position sensor. A loss of the camshaft position signal during startup will cause problems, however.

In your letter, you indicated the vehicle starts and runs normally if left to cool down. This is a tip-off that the crankshaft position sensor is thermally intermittent.

Kramer:
1) I would jump the the Crank Sensor as a "last resort. HBHRacing has the right idea, check other sources first.
2)You definately want a torque wrench that goes AT LEAST to 110ft/lbs. "Home Depot" torque wrenches are not held up to the same accuracy ratio as "Snap-On" torque wrenches. You want a wrench that ideally goes from 0-150 ft/lbs, and not one where 110ft/lbs is near the end of the spectrum (ie: 0-125ft/lbs, or 100-200ft/lbs))

[ October 14, 2004, 08:27 PM: Message edited by: C.O.Jones ]

[kramer2125]

Thanks for the advice on the wrench. I'll grab a new bolt too.

I posted about this problem before under "won't turn over" in this same forum. I checked the fuel pressure with a pressure test kit from autozone and i got 40-43 psi with every check. Hooked it up to the schrader valve, and the whole 9... In the comment to check for spark, you stumbled upon the cause of my problem. I had the ICM and coils checked at autozone, and they're both fine. I pulled the plug wire off of the plug, and removed the boot, then while the plug clip was held close to a metal object, i had my friend turn the igniton. No spark.

I have 38k miles on the y87 equipped 'bird. She has a new fuel filter (1k miles) new battery (5k miles) new plugs (installed today)new wires (installed yesterday) i'm also sure i have the plug wires in the right places b/c i d/l the diagram. I feel like i have the bases covered, cept for this Crank Sensor.

I do have an 02 sensor (the one after the cat) hanging in the breeze. Its wiring harness is clipped in. But the sensor itself its kept from scraping the ground by a bent coat hanger, (until i get an o2 sim). But i'm told this will not keep er from starting.

Before i had misfiring b/c i had 2 plug wires in the wrong places, it ran for probably a week like this before it was fixed. Could running w/ plug wires in the wrong place cause a Crank sensor to die?

[HBHRacing]

you can't "jump" a hall effect sensor. It will not work. The crank sensor behind the crank pully is a dual hall effect sensor. It uses the slots on the dampner to create a signal that both the PSM and module uses for both ign timing and fuel injector control. you need both the 18X crank signal and the CKP sync sinal for the module to make the 3X signal for the PCM.

If either the 18X or the CKP (crankshaft position) Sync pulces are NOT present at startup the engine WILL NOT start since no injector pulse will occur.

[C.O.Jones]

Originally posted by HBHRacing:
you can't "jump" a hall effect sensor. It will not work. The crank sensor behind the crank pully is a dual hall effect sensor. It uses the slots on the dampner to create a signal that both the PSM and module uses for both ign timing and fuel injector control. you need both the 18X crank signal and the CKP sync sinal for the module to make the 3X signal for the PCM.

If either the 18X or the CKP (crankshaft position) Sync pulces are NOT present at startup the engine WILL NOT start since no injector pulse will occur.

I agree. However comma in my vehicle I managed to screw up the thermostat gasket when installing my new thermostat. This caused Antifreeze to leak down onto the sensor. The car would start fine and run, but once hot it would cut out. I could be sitting at a light, driving down the road at 50mph, you name it, the car would die. I learned really quick that if I flipped on my manual fans for 20-30 seconds after the car died, the engine would cool off allowing me to start it again and move forward a couple miles. If I didn't allow it to cool, I was not able to start it (or it ran REALLY rough... did that once), and could not until it did cool.

After having it checked out by my dealer (with a Tech 2) they told me the cause of the problem. I limped the car home and changed out the sensor. The old sensor had a lot of crap between the magnets in the sensor. Why it only died under heat I don't know, but your car can start and run with a bad sensor... it'll just stop running during freeway traffic, resulting in you being pushed off to the side of the road by a cop who just so happened to be right behind you.

[HBHRacing]

"acording" to GM. once the car is started and the 3X signal is generated from the ICM even if you lose the 18X signal and the sync signal the 3X will keep the car running in a projected seqencal mode. I have yet to see this actualy work tho. I have seen a faulty cam sensor cause the motor to run in Bypass mode but yes, I have seen an intermitent stall (usualy when hot) caused by the crank sensor.