Auto Service Professional

DEC 2018

Magazine for the auto service professional

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Page 21 of 61

20 A S P D e c e m b e r 2 018 T e c h s H e l p i n g T e c h s A faulty CKP (or CKP circuit) can easily cause an intermittent misfire, which naturally results in what the driver may perceive as a surg- ing effect. A bad CKP can also cause a no-start and intermittent stalling issues. e root cause may involve a faulty CKP, or in rare cases, damaged or missing teeth on the wheel or metallic contaminants on the teeth. In even more rare cases, the reluctor wheel may have loosened (these are press-fit to the crank). Naturally, another possibility would be a short or open in the sensor wiring harness. If the wheel loosens and moves out of position (out of phase or crooked), and if this problem is suspected or confirmed, this must be addressed immediately, since a loose reluctor wheel can not only cause misfiring issues, but if severe enough, can also create mechanical damage (block interference or possible piston skirt dam- age). If, on the rare occasion that a reluctor wheel must be replaced or repositioned, DO NOT at- tempt this without the specialty tool required to properly register the wheel in-time with the cranksha. is service is best performed by an engine builder who is familiar with the specific engine type at hand. If the problem is mechanically severe enough, the easy way out would be to replace the cranksha with a new crank that already features a properly installed reluctor wheel. e installed phase position of the wheel is critical. Mark Patterson Patterson's Garage STICKING SPARK KEY We recently had a 2013 Chevy Spark come into the shop, with the owner complaining that the keyless entry remote is inoperative at times. We quickly found that this was caused by the The ignition would sometimes stick in the upright position, preventing a start using the keyless remote. A bit of lube and working the key back and forth offered a simple fix. The purple wire at the starter solenoid may not be fully seated. Check for flashing on the plastic, which can be trimmed to obtain a solid connection.

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