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  Tech Tips

The Importance of Proper Flywheel Installation

Posted 05/1/2013
By Paul Kujawa

How to test the system.

We have received several calls on mid-2000 model year Nissans that have a no start, hard start or poor running problem after the clutch has been replaced. Often there are codes set as well for the camshaft position (CMP) sensor, crankshaft position (CKP) sensor and/or intake valve timing (IVT) control system. The vehicles referred to in this article have a V-6 engine with a CKP sensor at the back of the engine that picks up a signal from a reluctor on the flywheel.

If the flywheel is removed when the clutch is replaced or is removed for any other reason, the flywheel needs to be properly reinstalled to avoid these problems. There is an alignment dowel on the rear end of the crankshaft that is used to properly align the flywheel with the crankshaft. The flywheel will bolt onto the end of the crankshaft in several positions – but only one is correct. A specific alignment dowel hole in the flywheel needs to be placed onto the alignment dowel. This dowel hole is in the shape of a “D” or “double D” and looks different from any of the other holes in the flywheel.

Using a scan tool, check the scan data to look for IVT degrees of advance. The IVT degrees should be at 0 degrees for both banks at idle when the crankshaft to camshaft phasing is correct. The engine control module (ECM) uses a CKP sensor and two CMP sensors to determine the relationship between the crankshaft and the two camshafts. A lab scope or an oscilloscope with at least three channels can be used to scope check the phasing of the CKP sensor and the two CMP sensors. If only a two-channel scope is available, the two CMP sensors can be checked for phasing and then one of the CMP sensors can be checked with the CKP sensor. Compare the phasing pattern of the sensors with a known good phasing pattern.

Phasing problems between the CKP sensor and the two CMP sensors can also occur due to a timing chain problem. But if the clutch was recently replaced, or the engine or transmission was replaced, the problem may very likely be at the back of the engine with improper flywheel installation, or a possible damaged CKP sensor reluctor on the flywheel.

Please contact us if you have any questions.

Paul Kujawa

Paul Kujawa is an Identifix Asian certified specialist. He is a Nissan and ASE master with L1 certification.

Experience Identifix This information is provided by IDENTIFIX®, an ASA-sponsored benefit provider. ASA members enjoy a special introductory rate on IDENTIFIX®'s vehicle diagnostics, repair and maintenance information.

Learn more about this benefit and ASA's entire member benefit portfolio at For more information on IDENTIFIX, call (800) 288-6210, 8 a.m. - 6 p.m. Central Time.

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