Project My2K: Part 11

Buying Used and Getting Back to Basics

This Ford Super Duty project is nearing an end but not before we finalize a few finishing touches to really dial in the drivability and overall performance of the old 7.3L under the hood. Project My2k has made quite the transformation over the past year and continues to outperform initial expectations. The new suspension, steering and power upgrades have made this truck extremely dependable to daily drive, while handling our towing needs when we need it to. We’ve installed one of KC Turbos new 63mm drop-in replacement turbos, and paired with the Edge Revolver tuning, it feels pretty strong down low while towing. Unfortunately, didn’t see the change in peak boost and top end we were expecting, and had to spend some time performing some diagnostic checks. After checking for boost leaks, to which we found none, we turned to our Edge Insight monitor to data log some of the information we can monitor through the OBD-II port.

One of the key issues we experienced with this truck was its inability to main injection pressure under load. While towing, or under heavy acceleration, you could watch the Injection Control Pressure plummet while the high pressure oil pumps duty cycle maxed out trying to maintain the requested 2800-psi. This data proved the factory HPOP was weak and need of replacement. Rather than an OE reman, we opted to upgrade to the Terminator T500.

Replacing the high pressure oil pump in a 7.3L Power Stroke can look like a tough chore, but in reality, it can be done in just 1-2 hours with the proper tools and some patience. Removing the factory fuel bowl (which we already did once when we rebuilt it and replaced the leaking O-rings) gives you easy access to the HPOP and the high pressure oil lines.

By watching our trucks injection control pressure and high-pressure oil pump duty cycle under wide open throttle we were able to pinpoint our lack luster power gains. With our tuning asking for 2800-psi of injection pressure from the high-pressure oil pump, we were able to watch in the data log that once we hit wide open throttle, the ICP would spike up to 2700-psi then quickly fall and settle at just 1850-psi. Knowing that our IPR (injection pressure regulator) valve was in good working condition the only explanation could be a weak and tiring pump. The factory high pressure oil pumps used on the 7.3L Power Stroke are normally a pretty solid piece, but like anything, miles and time can reduce efficiency of any part, and that 20+ year old pump just couldn’t keep up with the demand under load. Obviously, this meant we would need to replace the pump, but in the spirit of building this truck back better than it was new, we weren’t content with just a stock reman unit going back in and turned to Terminator Engineering for one of their modified replacement HPOP’s.

With the fuel bowl removed, you can see the HPOP mounted on the backside of the front engine cover, nestled snuggly right in the valley of the engine block. There are two bolts that hold the pump to the front cover, two high pressure oil lines that need disconnected, the Injection Pressure Regulator connector needs disconnected, and then the HPOP gear bolt needs removed through the access port on the front of the engine cover.

On the 1999-2003 7.3L Power Stroke, Ford used a special push lock style fitting on the high pressure lines that will require a special HPOP line tool to disconnect. Two flathead screwdrivers can be used, but it’s not easily done that way. You need to slip the tool in between the plastic keep and the flared section of the fitting to release the internal clip within the fitting.

The T500 developed by Joey Omlin of Terminator Engineering has been on the market for over 10 years now and has proven itself to be a solid option on the aftermarket for both longevity and performance in the 7.3L Power Stroke applications. Using some proprietary internal upgrades, the T500 remanufactured pumps can not only increase oil volume through the pump but maintain or even outperform tuning requests for injection pressure. The 7.3L hydraulically fired injectors have proven to offer best performance around 2800-psi, but and additional couple hundred PSI can further improve fuel atomization within the cylinder for a crisper throttle and broader torque curve.

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On the front of the engine, the HPOP bolt cover needs to be removed, which is where the Exhaust Back Pressure Sensor is mounted. So, removing the back pressure tube from the bottom of the bracket will be required. Which makes this a terrific opportunity to replace the tube and sensor since they’ll be out.

With the factory cover removed, you’ll be able to gain access to the bolt holding the pump gear onto the pump itself. A long ratchet will be required to break loose the bolt, and possibly the help of a friend to hold the belt to keep the engine from trying to rotate while breaking the bolt loose.

The factory high pressure oil pump can be found nestled tight down in the valley of the engine block, right below the fuel bowl. The access the pump for replacement, that fuel bowl will need to be removed, which with the right tools will only take about 30 minutes of time. With the fuel bowl out of the way, the pump will be easily accessible and only has a couple of high pressure oil lines and two bolt holding it in place. The factory oil lines will require a special tool to disconnect, but it is straight forward. Before the pump can come out of the engine bay completely, there is a large pump gear bolt that has to be removed through an access port on the engines front cover. Installing the new T500 pump is no different that installing a factory pump. You will want to be sure you use a new gasket to seal the pump to the back of the timing cover and possibly replace the seal rings on your fuel bowls fuel lines when it goes back together for safe measure.

With our factory 170,000 mile pump removed and on the bench, we can move our Injection Pressure Regulator over from the stock pump to the new T500 pump and get going with the reassembly so we can get back on the road, making pressure like we should.

While the T500 may still be a remanufactured oil pump, Terminator Engineering does a thorough job of cleaning, tearing down, and assembling the parts to look like brand new. Including new fittings and O-rings so you can be sure to get thousands of trouble free miles from the pump.

Once the pump is re-installed and the oil system is sealed back up, the truck will crank for quite some time while the low pressure pump works to refill the high pressure reservoir and start pressurizing the system. The injectors need to be able to see 500-600psi from the pump before they’ll fire and run, so it does take some cranking time. Be sure to have a battery charger available, and give the starter motor a break occasionally so it doesn’t overheat. Once the truck eventually fires up, don’t be alarmed if

It runs rough for a few minutes. Stumbling, stalling, and an erratic idle can be expecting while it tries to work the air bubbles out of that high pressure system.

The factory IPR valve needs to be removed from the stock pump, which can be done by first loosening the small tin nut on the end and sliding the outer magnetic assembly off of the valve itself to get better access and grip on the nut you’ll need to loosen to remove it from the pump.

With the valve removed from the pump, you’ll get a good look at how this IPR actually works and the small orifices used to control that injection pressure by regulating flow through the pump.

A couple easy upgrades worth doing while the HPOP is being replaced is the exhaust back pressure tube and sensor. The factory sensor is mounted on the HPOP gear access cover, so the tube and sensor have to be removed during the pump change. Over time, it’s common for that exhaust back pressure tube to get clogged and restrict flow to the back pressure sensor. Since the trucks computer and tuning calibrations can be affected by what the back pressure sensor tells it, this restriction and incorrect reading can lead to poor fuel mileage and sluggish throttle response. The factory access cover is sealed to the front cover with a silicone bead, but to make your installation process go easier, Riffraff Diesel offers a trick billet cover plate that is machined to accept an O-ring. We also picked up our new stainless back pressure tube and a Motorcraft back pressure sensor from Riffraff as well.

A very important part of this process is making sure you use a good high quality gasket when reinstalling the pump onto the back of the front cover. We snagged this one from the local diesel repair shop.

Going back together in the engine bay, it’s as easy as just installing the mounting bolts, installing the pump gear and putting all the oil hoses, fuel bowls, and fuel lines back together.

Since we had the HPOP access cover removed, this was the perfect time to upgrade and replace there as well. The billet HPOP cover from Riffraff Diesel, we also ordered a new Motorcraft exhaust back pressure sensor and replacement stainless back pressure tube from them.

After working all the air from the system and driving the truck for 10-15 miles, the engine was back to starting like it should and idling smooth as glass. Certain that the engine was running like it should, we again turned to our Edge Insight CTS3 monitor to collect those previous data points one more time. So, watching that ICP and Duty Cycle we could see that our pumps duty cycle had dropped quite a bit while we had no problem maintaining the demanded 2800-psi at wide open throttle. We had even seen the pressure spike over 3000-psi under initial tip in of the throttle. With no real need to check our data logs, we did so anyway and the ICP curve stays flat as could be while under hard acceleration, keeping our pressure right where it needs to be. This increase of over 1000-psi is definitely noticeable in the driver seat, and you can feel how much stronger the truck pulls through the RPM range. The most telling evidence outside of that ICP number on the monitor is the change in overall boost pressure. We picked up 5-psi of boost at wide open throttle. There is no doubt the truck picked up power, while it also cleaned up what little smoke we were seeing come out the exhaust pipe. All this data tells us we’ve gained power, improved atomization, and improved engine efficiency.

The new HPOP cover uses a square O-ring to seal against the front cover instead of silicone, which makes this a much cleaner job when going back together. The O-ring also makes future services easier as we won’t have to deal with silicone and cleaning the surface ever again.

The new stainless steel replacement tube doesn’t really offer any performance gain, with the exception of the original tube possibly being plugged up with 20 years’ worth of soot. The restriction built up over time in the tube can lead to false readings of the back pressure sensor, which can then cause the PCM to make incorrect adjustments in your tuning. This could mean poor throttle response and a loss of fuel mileage.

On the chassis dyno at Edge Products, we were able to see just what our truck gained with the new pump installed. With the right oil pressure, our truck picked up exactly 20hp at peak, and now carries the torque much further through the RPM range.

As we near the end of this older Ford Super Duty build up, there are still a few pressing issues we need to attend to, like some upgrades for our cooling system and we’re going to upgrade the charge air system so we can be sure we’re making the best use of all that new boost and airflow being fed to the engine from our new turbocharger.