The magnetized Pulley on Nissan and DTC P0340
[Illustration omitted] Full version (pdf. Rus)
1998 Nissan Primera P11 QG18 (1.8 L / Gas) LHD, Europe
Fuel: Fuel Injection
Trans: 4-speed Automatic Transaxle (Electronic)
Vehicle came in from dealer Service Shop with this code P0335 after replaced the Crankshaft Position Sensor and checked the harness back to the computer. But this DTC again returned. Car had the stumble/ A slight hesitation (Staggers) when accelerating at approx. 2,000 rpm and rough Idle.
By checking Car it was found out that with the slow opening of throttle plate the engine categorically rejected "to untwist" more than 2000 r/min. With usual opening of throttle - in this range Engine had small trembling, but everything was almost in norm with the higher speed of engine. Checking control of Coils showed that approximately with 2000 rpm the driving pulses became chaotic (not synchronous) and this explained the reason for the described behavior of engine. However, the first tapping of the motor-analyzer (but it was already understandable that "battle" would be difficult) showed the reason for the strange behavior of the Car. On these two graphs signals of both sensors of this Car are shown (Im.2. Signal with the working condition and Im.2. Signal with the defective condition) with the difference in the writing of fraction of a second. With the naked eye one could see how spontaneously the duration of the "single" Pulse of the Camshaft Position Sensor increases.
"Who is guilty?" and "What should be done?" are age long questions not only of the Russian Intelligentsia. To answer the first question, i.e., for checking the Camshaft Position Sensor offhand the "Stand" was prepared where it was possible to check sensors "on the table”, and without tormenting the car. On Photo 2 "Stand for checking the sensors” its fragment is shown. The part of Distributor Toyota, the remains of the old microphone holder, electric drill with the home-made adaptive speed regulator of rotation, adapter for the connection of sensors, usual oscilloscope helped to ascertain that all sensors worked well. Any (at that moment) reasonable actions didn’t resulted in the previously obtained effect. All three Sensors worked completely proper. Version "malfunction ECM" was more than improbable.
Situation became stalemate. Sensors are good and Chain stands almost new and correct timing Mark on the spot and notorious NTB on this topic "kept silent as a fish". The sad situation from the Nissan history had come to mind about the magnetized shafts of QG18DE, QR25DE, VQ35DE engines because of which 2,5 mln cars were recalled, but this version arose not immediately. And its checking took some minutes. The magnet was placed to the rotor and miracle has happened. The sensor Signal with the checking on the "Stand" became more than similar to the signal of the sensor of that established at the Car. Additional checking after the removal of valve cover and with the aid of the needle suspended from the thread confirmed the magnetization of the pulley of the tappet shaft of this machine.
On the second of the eternal questions of Russian colleagues was already easier to answer. For sure elderly readers can recall the distant Soviet times, when tele-masters took to the call the so-called "loop of demagnetization". Sometimes only after its application one could succeed to adjust dynamic information of the rays of the colored kinescopes of any ULPTST -... of those years. Unfortunately home-made loop was not preserved, but in the pantry of a friend original one was found, (photos 3. Loop of demagnetization). Several minutes of the demagnetization of pulley, and signal (photo 4 Scope of fixed Car) sensor were good, Car ceased to be twitched. And certainly the indicator of malfunction ceased to be included with the brought engine. It goes without saying, this malfunction cannot be carried to the mass, but its originality allows the publication of this small description.
Waveforms CKP (POS) vs. CMP (Phase) Sensors at DTC P0335 on QG- Engines
Translation courtesy by Hanna & Ljudmila Shelest