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Jeep Smog Pump Rehash - Jp Magazine

Rick Péwé Editor-in-Chief, 4Wheel & Off-Road Photographers: Rick Péwé

Back in the late '70s and early '80s, the much maligned smog pump was being ripped off of engines left and right by Jeep owners in search of more horsepower. Back then, the thinking was that the pump not only didn't do any good, it hurt horsepower by being beltdriven off the engine. And in those days, who checked for pollution equipment anyway?

154 9901 Smog Pump Rehash emission System Diagram Photo 30777238

Nowadays, most people know that the OE smog pumps actually make the engine run better, help somewhat with tailpipe emissions, and have minimal parasitic drag on the engine. But most importantly, new smog laws require the original equipment controls to be in place and functioning, or, in many areas, you can't register your Jeep.

Rather than swapping plates with a legit vehicle or moving your Jeep registration to Bolivia, the easy way to pass inspection is to renovate the Air Injection System (AIS). The problem lies with finding the necessary parts at the right price. If you've ever been to the dealer, you know how expensive all the components are-if they're still available. And junkyard shopping will yield the same results. Most components are indeed junk after sitting for years; the ones of any value have been carried off by those who got there first.

154 9901 Smog Pump Rehash 4 Wheeler Supply Smog Pump Kit Photo 34756854 The complete smog pump kit from 4 Wheelers Supply has all the parts needed to refit the AIS. The driver-side manifold spider has only three hookups, since the power brake booster is in the way. All the factory exhaust manifolds are made that way, and the system bolts right in.

The solution is to buy the components in a kit. We found that 4 Wheelers Supply in Phoenix, Arizona, stocks the popular Jeep applications as well as many Chevy and Ford kits. 4 Wheelers has been a specialist in parts and service for Jeeps for over 40 years, and was able to supply a kit that's complete down to the vacuum tubing.

The kit we installed for an AMC 360 V-8 equipped with power steering came with the air pump, manifold tubes, check valves, diverter valve, pump brackets, and all the hoses, clamps, and bolts needed. Follow along to see how easy it is to get your Jeep emissions-legal as far as the smog pump system.

PhotosView Slideshow This is how most manifolds look when the correct parts are missing. A big bolt with the wrong size threads jammed into the manifold to plug the hole (arrow). Luckily, the threads are the same as on a standard spark plug, so a thread chaser can be used to clean up the hole after the old bolt is removed. The special bolts are supplied in the kit to fasten the spider to the manifold. A steel gasket goes on each side of the fitting, then the bolt is tightened snugly, just like a spark plug with a gasket. Antisieze lubricant on the bolts will make removal easier when necessary. The check valves keep exhaust gasses from blowing back to the air pump and need to be installed on top of the spiders. Coat the threads with antisieze lubricant before installation because the components will wear out over time and someday may need to be replaced. Route the spark plugs around the new spider to prevent any heat damage to the wires. The hoses are installed on the check valve (arrow) and secured with a hose clamp. Extra hose is supplied for the different accessory requirements of the various engine installations. Hoses from both check valves attach to the diverter valve (arrow), which has another hose that goes to the air pump. The diverter valve doesn't mount to anything stationary, just as in the original setup. Instead, it hangs in mid-air supported by the three hoses that are attached to it. The supplied vacuum hose slips onto the fitting on the diverter valve, then goes to the ported manifold vacuum off the carburetor. The diverter valve operates off a vacuum source to cut off the flow of air at high rpm (high-manifold vacuum) and give full flow capabilities at low speeds (low-manifold vacuum.) On power steering applications, only two small brackets are needed to bolt the air pump on. The lower fixed bracket bolts onto the aluminum power steering bracket underneath the power steering pump (arrow). The upper adjusting bracket also bolts onto the power steering bracket as shown, with the air pump bolted in between the bracket, using the supplied bolts. The hose from the back of the pump runs up to the diverter valve previously installed. The pulley is bolted onto the air pump after the pump is mounted. Depending on your belt alignment, the pulley can be installed to match up with the front or rear groove in the power steering pump pulley. The position shown is for the front pulley, but depending on the belt arrangement, the pulley can be reversed to line it up with the rear groove, as indicated by the factory installation. Since belt lengths varied in the original installation, the belt isn't included in the kit. Simply measure the length of the belt needed to drive off the power steering pump and order one from your local auto parts store.