Where is the air pump located on the 4.9L engine?

According to the diagram, the air pump (highlighted in red) is mounted low toward the front of the engine, with a hose running up to the air bypass valve.

Where is the air bypass valve on this engine?

The diagram shows the air bypass valve mounted high on the engine near the accessory bracket area, connected by hoses to the air pump below it.

Where does the check valve go in the secondary air system?

The check valve is shown inline in a hose at the opposite end of the engine from the air pump, at the end of the air tube that runs along the cylinder head.

What components make up the secondary air system shown in this diagram?

The diagram labels three components: the air pump, the air bypass valve, and the check valve, connected by hoses and a tube along the engine.

Home/ Registry/ Ford/ Bronco/ 1987-1991/ “Eddie Bauer”/ Photo supermotors.net/registry/media/988578

1990 Ford Bronco 4.9L Thermactor Air Pump, Bypass & Check Valve Diagram

Color-highlighted air pump diagram with air bypass valve and check valve

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Secondary air schematic with color-highlighted air pump, air bypass valve and check valve plumbing at the front of the engine.

AI caption July 2013 · Photo 1566 of 1799

This document is a factory-style line-art schematic of the secondary air injection (Thermactor) system components on an inline six-cylinder Ford engine, consistent with the uploader's claim of a 1990 Ford Bronco 4.9L with automatic transmission. The drawing shows the engine from the side with an arrow indicating 'FRONT OF ENGINE.' Three key emissions components are highlighted in red: the belt-driven AIR PUMP mounted low at the front of the engine, the AIR BYPASS VALVE mounted higher on the engine near the accessory bracket, and an inline CHECK VALVE located in a hose at the left (rear) of the illustration. Shaded/gray hoses illustrate the air routing: from the air pump up to the air bypass valve, then along a hard tube/manifold running the length of the cylinder head, and to the check valve hose. The figure reference number A13527-A appears at the bottom right. A reader can learn where each secondary air component is physically located on this engine and how the air hoses are routed between the pump, bypass valve, and check valve, which is useful for identifying, testing, or replacing Thermactor system parts.

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Frequently asked questions

Where is the air pump located on the 4.9L engine?: According to the diagram, the air pump (highlighted in red) is mounted low toward the front of the engine, with a hose running up to the air bypass valve.
Where is the air bypass valve on this engine?: The diagram shows the air bypass valve mounted high on the engine near the accessory bracket area, connected by hoses to the air pump below it.
Where does the check valve go in the secondary air system?: The check valve is shown inline in a hose at the opposite end of the engine from the air pump, at the end of the air tube that runs along the cylinder head.
What components make up the secondary air system shown in this diagram?: The diagram labels three components: the air pump, the air bypass valve, and the check valve, connected by hoses and a tube along the engine.