Location of crankshaft sensor on 92 Pontiac Trans Sport?

Answer 1

On 1990 through 1995 General Motors 3.8 L engines, the crankshaft positioning sensor was located under the harmonic balancer on the left side of the engine.

The harmonic balancer is attached to the main crankshaft and must be removed through an access hole located in the right passenger wheel well. Remove the right front passenger tire after jacking up in stabilizing the vehicle. Inside the wheel well is a small plastic panel that can be removed to access the harmonic balancer mounting bolt. Remove this bolt from harmonic balancer. Using a small wheel puller on the harmonic balancer, gently tap and tighten the wheel puller to remove the harmonic balancer itself. Caution -- be very careful while doing this! The harmonic balancer has a soft aluminum rings attached to it that can easily be bent during the removal process. If they are bent, they will not work properly and will damage the crankshaft positioning sensor! Once the harmonic balancer is removed the crankshaft positioning sensor and wiring is exposed for replacement. Follow the wires leading out of the crankshaft positioning sensor to the electrical wiring coupling. Uncouple this union to disconnect the electrical wires of the crankshaft positioning sensor. Carefully clean the area around the old sensor while still mounted on the vehicle. He is a permanent magic marker and carefully outline for Mark the position of the harmonic balancer before removal. This Is Very Important! If the new crankshaft positioning sensor is not in the precise position as the old one removed, it can cause a no pulse situation to the mission module, which produces the sparkplug timing and firing to the sparkplugs. Crankshaft positioning sensor is held on to the engine by two bolts. Carefully remove these two bolts and the old sensor. Clean the area behind the old sensor with steel wool to make a clean surface for the new sensor mounting. But the new crankshaft positioning sensor in place were the old sensor was removed, follow closely the marks made earlier to position the new sensor at the right location. Mount the new sensor with the two bolts that were removed. Attach the electrical wires from the new sensor following the same path as the old wires on the sensor removed and reattach the electrical coupling to the wiring harness. Carefully replace the harmonic balancer back in place on the crankshaft. Do Not Force the harmonic balancer if you feel any resistance! The circular aluminum fins attached to the harmonic balancer may be pressing against the crankshaft positioning sensor if the crankshaft positioning sensor is not aligned correctly. If you feel any resistance from the harmonic balancer you'll have to climb into the engine area and carefully check to see if the new crankshaft position sensor is in the right location to allow the aluminum fins on the harmonic balancer to fit between slots on the new crankshaft positioning sensor. If the slots do not accept the fins on the harmonic balancer, slightly loosen the two mounting bolts for the sensor and reposition it where you can clearly see that the slots will accept the aluminum fins on the harmonic balancer. Once you have done this, lightly slide the harmonic balancer back into place and check again at the aluminum fins fit cleanly into the slots of the new crankshaft positioning sensor. With the sparkplugs removed, it is possible to rotate the crankshaft and harmonic balancer clockwise to ensure the aluminum fins pass cleanly through the slots of the crankshaft positioning sensor. Once you have verified this, re-tighten but not over tighten, the mounting bolts on the crankshaft positioning sensor. Reinstall the harmonic balancer on the crankshaft and replaced the bolt that holds it to the crankshaft. Be sure to tighten this bolt securely. Again and rotate the crankshaft clockwise by hand very slowly. Listen and feel for any resistance at the harmonic balancer to this turning. If you hear any, remove the balancer and check the crankshaft positioning sensor alignment again. If no resistances felt, the job to be done. Using a cheap spark detection tool, available at most part stores, you can have someone cranked the engine and check for spark plugs. If you have installed the new crankshaft positioning sensor correctly, have it aligned correctly so that the aluminum fins on the harmonic balancer ride smoothly through the slots, you should see spark now at the plugs. This is assuming of course all of the components, the ignition module, the coil packs, and electoral connections are in good working order. When the engine is running and the harmonic balancer rotating on the crankshaft with the aluminum fins sliding through the crankshaft positioning sensor, this provides electrical control pulse to the ignition module, that tells it where the crankshaft position is and regulates when the spark to each plug is released. In this Distributorless design, the crankshaft positioning sensor is a simple Hall Effect switch. While not very complex, it is an integral part of the Distributorless SPARC system for the vehicle and often is suspect to failure. The failure of the crankshaft positioning sensor causes a no spark situation at the plug and the engine just stops running. This can happen at any time. Meaning, you can be driving along, the engine is running fine and then it just suddenly quits! After a short period of time, you can suddenly restart the engine and it runs fine again. This condition generally is caused by the crankshaft positioning sensor overheating and stops producing the needed control pulse to the ignition module which controls the spark at the plugs. Many mechanics misdiagnosis this problem when the vehicle is brought in. 1990 to 1993 onboard computers do not have a trouble code for a bad crankshaft positioning sensor. 1994 and up vehicles have a different onboard computer, called OBT2, and a trouble code for this condition. An intermittent crankshaft positioning sensor can also cause erratic engine operation, from rough idling and power loss, to poor gas mileage. As a general rule, if your vehicle as the 80,000 to 125,000 miles on it, it is a good preventative measure to replace the crankshaft positioning sensor, even if you are experiencing no problems with it. The crankshaft positioning sensor only costs about $35 at most part stores but because of its critical role, it is a part not be ignored in preventative maintenance. I hope this helps some people resolve a serious condition I call The Sudden Stop Syndrome. Otherwise, a 3.8 L V-6 engine has been a fairly reliable engine for General Motors. If you have any questions, be sure your vehicle is serviced by a competent mechanic. C.08 - DERICKUSA1