Used Throttle BodyUsed Throttle Body

One of the most overlooked aspects of a fine running vehicle is the throttle body. An automobile’s throttle body is a small, yet extremely important piece involved in the ability of a vehicle to run smoothly and efficiently.

What does it do?

Attached directly to the intake manifold, the throttle body is responsible for determining the correct ratio of fuel and air to be dispersed into the intake manifold, where it is then distributed through the valves of the head(s) where it then enters the cylinder to be detonated. Issues involving an engine that runs roughly, whether it be hard to start, sputtering on take off, cutting out or surging at any RPM, or just running roughly in general, are many times the result of a problem at or around the throttle body.

Throttle bodies on most modern day vehicles are assisted in doing their job by various sensors attached to them. A few examples of these sensors are the MAF (mass air flow) sensor, the MAP (manifold absolute pressure) sensor, the IAC (idle air control) valve, and the TPS (throttle positioning sensor). All these sensors work together to provide real-time data to the engine’s computer, which is then able to regulate the correct mixture of air and fuel that flows from the throttle body and into the intake manifold, allowing the engine to run at the most efficient level possible given the current conditions. The state of the current conditions include things such as the outside air temperature, the aggressiveness of the driver relative to the gas pedal, and also any possible vacuum or pressure leaks in the system.

Sensor damage and/or malfunction is a common occurrence, and any fuel or air delivery issues should lead to initial troubleshooting in this area. Most code scanners that connect to the engine computer via the OBDII port are able to pinpoint the exact cause of the issue, however someone savvy with handheld electrical testing equipment could also use this method to determine the cause of any issues. Occasionally, the issue will be with the throttle body itself, where something such as excessive heat or physical impact with another solid object could result in warpage, cracking, or even a heavily broken part. Should this happen, replacement of the throttle body is necessary.

Replacing a Throttle Body

When a throttle body replacement is needed, there are two possible routes to take: purchasing a new throttle body, or purchasing a used throttle body. A new throttle body will be more expensive, but can most likely be purchased with a warranty. For someone repairing their vehicle on a budget, however, purchasing a used throttle body is a very viable option. New fasteners will sometimes be necessary, and it is important to use the right sizes so it is often a good idea to bring your old fasteners with you to the parts store even if they are damaged or broken.