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Answers to All Your Jeep Questions

Posted in How To: Tech Qa on November 29, 2018
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Fuel Pump Solutions

In “Fuel Injection in a Box” (Dec. ’17) you added fuel injection to an older Jeep. I’m curious about the inline fuel pump. Would it be possible to get a part number for the fuel pump you used? My son has installed a fuel-injected Ford 302 engine and the fuel pump makes so much noise.
Boyd Phillips
Via email

The Holley (holley.com) Sniper EFI kit we installed on the Jeepster comes complete with a fuel pump. The pump is available separately under Holley part number 12-920. This inline fuel pump is rated for up to 80 gph at 15 psi and 62 gph at 60 psi. As you can see, the gph output decreases as pressure increases, but this pump should easily support the Ford 302 V-8.

Generally, you need to match the fuel pump output to the fuel injection requirement of the engine. If the pressure or volume is too low, the engine will not operate properly. Conversely, matching up an expensive high-pressure, high-output fuel pump with a stock low-horsepower engine is a waste of resources when a lesser fuel pump will do the same job just fine. The relatively inexpensive Airtex (airtexasc.com) part number E2000 inline fuel pump is regularly used for common fuel-injected engine swaps.

Now, if your pump is making a lot of noise, it’s likely that one of three things is happening. The pump is dead, is about ready to die, or the inlet filter to the pump is clogged and needs to be cleaned or replaced. Several different things can cause an electric inline fuel pump to fail prematurely. However, the most common reason for poor inline fuel pump performance and lifespan is installation error. The pumps can fail from a lack of fuel or if they are simply mounted improperly. An inline pump should be mounted as close to the fuel tank as possible but below the bottom of the fuel tank. The reason for this is that inline pumps are not typically great suction pumps, so they have trouble lifting the fuel from a tank. Mounting the pump close to and below the bottom of the tank keeps the pump fed via gravity and a siphon, once the initial suction is made.

Regularly driving with a low fuel level can decrease the lifespan of the fuel pump, especially with a wide and long fuel tank. As the fuel sloshes, the fuel pickup is uncovered and the pump sucks air, which over time can damage the fuel pump. Taller tanks with smaller overall footprints are less likely to cause fuel starvation issues at odd angles and fuel pump failure. You can get crazy with expensive fuel cells, but another solution is to use a Holley HydraMat. The HydraMat attaches to the inside bottom of your fuel tank. It soaks up fuel from the lowest point in the tank and has a broad reach across the bottom. It’s basically a tiny fuel reservoir system designed to reduce the fuel starvation issues common in hard cornering, acceleration, stopping, inclines, and low fuel conditions.

Another common cause for electric inline fuel pump failure is contaminants in the fuel. Hopefully, you’re running two separate filters on the fuel system. There should be a filter before the pump and a filter directly after the pump. The filter before the pump can be a traditional fuel filter, such as a Napa (napaonline.com) part number 3033. This filter is to keep the debris out of the fuel pump. The second filter, after the fuel pump, should be a 10-micron EFI fuel filter. This filter is needed to keep much smaller contaminants from clogging the fuel injectors. If you find that the first filter is clogged, you may want to check the fuel tank for rust and other contaminants. If you are using a fuel cell with blocks of anti-slosh foam inside, you may want to remove the foam. It’s not uncommon for the foam to break down after a year or so. The small bits of foam then work their way into the fuel filter and clog it.

Frame Rust Repellant

I am a longtime reader, first time messenger. I am currently going through a full frame replacement on my Jeep TJ. It suffered the cancer of rust to the point that it needed replacement for safety issues. My dad bought it new in 2000, and I have recently taken ownership (sentimental reasons). I am coming into the home stretch. I obviously want to come out ahead of where I started. I have seen various forums on drilling holes in the bottom of the frame to allow water, dirt, and debris to drain out, since currently there are no holes to allow this. Seeing how I’m a Northern state person, salt is a winter issue. Have you had any experience with this? I don’t want to have to do this again in another 18 years. I know rust is inevitable, but I want to alleviate any future headaches. I’m nervous about putting holes in a new frame, which may weaken its structural integrity. If your opinion is that it’s not a bad idea, how large of a diameter should I use? Thank you for your time! Keep up the great work.
Chris M.
Via email

Unfortunately, most Jeep frames eventually succumb to rust in the salted-road states. Cleaning the Jeep’s underside very well after each trip on salted roads and storing it inside during the winter when it’s not being used can slow the rust process. Also stay away from carwashes that recirculate and reuse the rinse water, they will simply spray salted water from other vehicles onto your vehicle.

Every TJ frame is coated inside and out from the factory with a protective coating. Drilling holes in, cutting, grinding, and welding on the frame will burn or remove that coating and give the rust a place to start eating away at the fresh metal. Generally, the TJ frames are eaten from the inside out. You can add extra protection to the inside of your frame with products like Internal Frame Coating from Eastwood (eastwood.com). The product comes in an aerosol can and includes a special 24-inch hose and nozzle that is pulled through the inside of the frame while spaying the protective coating. The coating is said to destroy rust hiding inside the chassis, significantly slowing the corrosion process. It is available in a black or green finish.

If you really want the frame to last a long time, you should inspect, thoroughly clean, and paint any chipped or rusty areas on the inside and outside of the frame at least once a year. If you do decide to drill a few drain holes, 3/8- to 1/2-inch on the bottom of the frame should be fine. Just make sure you carefully coat the bare steel left behind.

Body Weld Tips

I’m a garage hobbyist and need a little help. I’m trying to build myself some half-doors and I am struggling with welding the door panels. I have my welder turned all the way down, but no matter what I do, it burns through. Am I supposed to solder body panels? Throw me a bone.
Jack Brisbin
Via facebook.com/jpmag

Bodywork using actual tools is by far our least favorite modification to perform. However, over the years we have done several body mods that involved welding on thin sheetmetal. Getting perfect show-quality results will require a different process than what we propose, because adding too much heat to the panel will cause it to warp. We’re not “show-quality” welders, but assuming that you are just trying to get the two metal bits to stick together without warping, the first thing to do is to check the wire diameter in your welder. If you are running 0.035- or 0.030-inch-diameter MIG wire, you’ll likely want to swap it out for some 0.025- or 0.023-inch-diameter welding wire. The thinner wire will give you the ability to put less heat into the thin sheetmetal, avoiding a blow through. You’ll need to practice and fine-tune the wire speed and voltage settings prior to actually welding on your door project. If one of the panels being welded is thicker than the other, start from the thick part and focus your heat there, then drag the weld puddle into the thinner panel and back to the thick panel. For more delicate body metal projects, you may need to use a series of small tack welds. Skip around along the seam for each tack weld to avoid putting too much heat in one area. You can work your way back and forth until the panel is fully welded. Once you are done you can grind the tack weld bead smooth and use body filler as needed to smooth the area.

Restore or Modify

I have a ’63 Willys truck. Do you recommend replacing the drivetrain or rebuilding the 230ci inline-six?
Greg Madic
Via email

Whether or not you modify a Jeep really depends on several factors, including personal preference, what you plan to do with the Jeep, and what kind of budget you have to work with. As far as personal preference is concerned, I fully understand the appeal of keeping the stock engine in a stockish vintage Jeep. I also appreciate sleeper stockish Jeeps with more powerful engines. Having said all of that, I’m more likely to keep the low-horsepower stock engine if it runs and drives fine. If it needs major repairs, such as an expensive rebuild, I’m less likely to stick with the stock engine. The only exception would be if I could get my hands on a good used engine that would simply drop in place of my worn-out engine.

I typically look at every needed repair very carefully before spending any hard-earned cash. Will I be better off repairing what’s there, or upgrading it with something newer, better, or stronger? For example, would it make sense to throw money at a broken Dana 25 front axle if I planned to add more power and bigger tires down the road? In most cases, the answer is no. The same goes for your engine choice. If you plan to keep the Willys truck stock, the stock engine will typically move it around town just fine. However, if you plan to take the truck on long road trips or you want to tow, or turn it into a slop-flinging mud truck, you’ll likely need to consider swapping out the stock engine for something more modern, reliable, and powerful.

As far as budget is concerned, you have to be realistic. Will the engine rebuild be much less costly than an engine swap? If you do decide to swap the engine, what other components will need to be upgraded, such as the transmission, driveshafts, radiator, exhaust, axles, and so on. Another consideration is your Jeep project history. Are you a Jeep procrastinator that will tear down the entire vehicle, leaving it as a perpetual project for eternity? Eventually you’ll give up and sell it off for almost nothing with missing parts that have been lost and packed away somewhere in the garage or storage shed. If this is you, you may be better off with a less time-consuming project, so the engine rebuild makes more sense. Whatever direction you decide to go, good luck with your Willys truck project, and send us pics when you are done.

JK Suspension Extension

What amount of extension from ride height should the front suspension drop on a stock vehicle? There seems to be a lack of information for people in between full stock and going full tilt rockcrawler. I have installed a leveling kit and now believe I have limited suspension extension. I want to keep the stock ride height but lose the factory rake. I used the 2-inch TeraFlex spacer kit to bring the front up level with the rear. I also changed the shocks to Bilstein 5100 for the 1.5- to 3-inch lift (24.6 inches extended). With the longer shocks installed, my suspension drops only 2.5 inches from ride height. I didn’t note what the extension was with the stock Rubicon shocks and suspension, but 2.5 inches doesn't seem like much. Die-hard crawlers will say never let the shocks limit the suspension extension, but that’s the way it is on stock JKs. I used 2-inch bumpstop extensions so the shocks do not limit compression. So what is a good amount of extension for highway safety on a vehicle that doesn’t have a lift kit?
Stephen Shaw
Via email

Generally, a stock Jeep and most other stock 4x4s are set up with the suspension resting about in the middle of the available wheel travel at factory ride height. However, the total suspension travel of a typical 4x4 can vary by several inches, depending on the suspension design and manufacturer. So, the amount of downtravel built into the suspension can vary as well. On paper, you shouldn’t have the problem you are explaining. Stock JK Rubicon front shocks extend to 23.13 inches, to provide 8.5 inches of travel. If you have added 2-inch front coil spacers and your new shocks are 24.6 inches extended, you should have only lost about a half inch of suspension droop, which isn’t even noticeable. Keep in mind that suspension movement is often limited by other components besides the shocks. This could include the control arms, track bar, sway bar, brake lines, steering, or a combination of these components. Unfortunately, measuring the suspension droop can’t always be accurately done in the driveway; there is kinetic energy in play that can cause the suspension to extend further while driving down the road, or over a set of bumps off-road, than what you can mock up in the driveway or garage. The weight of the tires, wheels and front axle, along with the inertia of them moving at speed could increase the suspension droop by several extra inches in some cases, as long as the shocks are not topping out.

Safely raise the Jeep off of the ground by the frame and measure the front shocks to see if they are actually fully extended. It sounds as though they will not be. I suspect there is some other binding in your chassis or suspension. My first guess would be the track bar. My second guess is the sway bar. And lastly, check the lower control arm brackets on the front axle; they could be making contact with the lower control arms when the suspension is extended. Each of these problems has a fairly simple solution. The track bar binding can be remedied with an aftermarket adjustable track bar. Make sure the track bar you choose is compatible with your lift height. If the sway bar is the cause of the binding, longer aftermarket sway bar links will solve the problem. If you are on a budget, you might be able to use stock rear JK sway bar links. They are slightly longer than the stock front sway bar links but will bolt up just the same. As for the control arm brackets, if the lower arms are making contact, you’ll need to clearance the brackets with a grinder until the arms no longer hit during suspension extension.

Oil Change Interval

I have a ’78 CJ-7 that I drive about 1,000 miles only five months a year. I store it in the winter months. How often should I change the oil?
Gregory G. Grace
Via email

Recommended oil change intervals vary from vehicle to vehicle, engine to engine, and even on how it’s driven. Modern engines with tighter tolerances can typically go much longer between oil changes than their older counterparts. The oil change interval for older engines, such as any of the engines that were available in your ’78 CJ-7, is every 6,000 miles or 60 days, depending on driving conditions. But it doesn’t make a whole lot of sense to be changing the oil every two months as the Jeep sits through winter, right? You’ll be draining and recycling perfectly good engine oil. If you’re more on the meticulous side, consider changing the oil once a year. I’d recommend changing the oil and performing all of the regular maintenance prior to putting the Jeep away for winter. This way you won’t have any debris buildup settling at the bottom of the oil pan. It will help reduce sludge and your Jeep will be ready to hit the road or trail the following spring.

If you’re a bit more frugal, consider changing the oil every 2-3 years. Even though the oil will likely still be very clean (depending on how many trails you hit), putting a Jeep in storage can invite other contaminates into the engine oil besides dirt. Water, in the form of condensation, can make its way into the engine. It happens to almost every engine, but regularly starting and letting the engine warm up boils off the invading H2O. If the vehicle sits, that water in the engine can cause rust to form and make its way into the oil. Parking the Jeep indoors in a controlled environment will reduce the chances of this being an issue more so than if the Jeep is parked in a barn or under a carport where it’s out in the elements.

If you live in a dry area or park the Jeep in a controlled environment and almost never take the Jeep in the dirt, you could very easily stick to making oil changes every 6,000 miles, and you’ll likely be fine, aside from the sludge buildup at the bottom of the oil pan. Although, if you care enough to park the Jeep for winter to save the body from rust, don’t you think you should show the engine a little love too?

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