Categories : Auto Repair

Anti-lock braking concerns and variable valve timing

Serving Central Oregon since 1903 Q: I have a 2003 Toyota Highlander with 146,000 miles on it. It drives terrific, and I have actually never had any major problems with it. Just recently, I observed a strange thing occurring with the brakes. It first took place on a rainy day, and I believed that was the reason for the problem, however it started taking place on dry pavement also. When I press on the brake (not whenever, but sometimes) the anti-lock braking system engages and I get that pulsing motion on the pedal together with a small thumping noise, all things that are completely regular for an ABS on a snowy surface area. I took the vehicle to my mechanic, who examined everything and informed me that all the brakes remained in good condition. He said that if it began happening often, he might be able to obtain a code on the computer that would tell him exactly what was going on. Do you have any idea what’s wrong? A: This is a difficult one. Any possibility a company unintentionally over-inflated the tires? Beyond that, my inkling would be you might have a front-wheel bearing starting to loosen up due to wear and it’s causing that wheel’s speed sensor to become somewhat irregular when braking over bumps. A scan tool or laboratory scope graph of front and rear wheel speed sensor trademarks would show which sensing unit is setting off the issue. An intermittent signal dropout from among the four sensing units may likewise be the cause and may possibly be slipping under the built-in diagnostic system’s radar. Q: I keep becoming aware of variable valve timing on brand-new vehicle engines. Can you describe exactly what this is, how they do it and why I ‘d want it? A: Variable valve timing is a cool innovation that in fact surpasses timing and really helps with engine efficiency, fuel economy and minimizing emissions. There are a range of valve timing settings: differed, overlap, raise and duration. And there are numerous variations in VVT types, which fall into 2 categories: camshaft phasing and camshaft shifting. Cam phasing is achieved using a variable position center at the camshaft’s sprocket. Oil pressure, thoroughly metered by a computer-controlled solenoid, permits camshaft timing to be advanced or retarded from the normal position as much as 60 degrees. This can enhance both low and high rpm torque, decrease low speed pumping losses (improving fuel economy) and minimize oxides of nitrogen. Phasing might be used on a single camshaft, the intake camera only, or on both intake and exhaust cameras, depending upon engine type. Webcam shifting may involve moving rocker arms to extra webcam lobes, varying the rocker arm fulcrum point, utilizing an inner camshaft within a tubular external camshaft, or axially moving the camshaft to line up three dimensional lobes with the valves. Greater lift and period actually helps cause the power under the right conditions. Increased efficiency does come at a cost. VVT systems require clean and right engine oil for their elaborate parts to function properly. Poor upkeep or the incorrect oil viscosity can induce performance issues and an illuminated check engine light. This weekend, countless concertgoers are flocking to the Coachella music festival, … more
See all stories on this topic

Infiniti I30 Engine Diagram

repair service diagrams for infiniti i30 engine transmission – wiring diagrams for infiniti i30 automobiles oem drawn wiring diagrams for most infiniti i30 cars …
See all stories on this topic

You may know another individual or company that needs auto, truck, or diesel repair... or even on site fleet service. Please tell your friends. It's much appreciated!