Powerstroke 7.3l and 6.0l engines use a high pressure oil system to fire the fuel injectors. This system uses engine oil under high pressure combined with voltage from the injector module in order to push the fuel (45-65 psi) out the tip of the injector. This system works great when it has no leaks and allowed for the earlier Powerstrokes to achieve higher injection pressures to atomize the fuel and burn cleaner. The problem with the high pressure oil system stems from it’s tendency to develop leaks and also the fact that the engine can not run without base oil pressure (which can be a benefit being you can never run the engine with no oil). The truck I’m gonna talk about today is a 1997 F-250 that was towed to our shop after a previous shop had built the engine but could not get it running.
When we first started looking at this truck we connected the scanner so we could verify how much injection pressure the ECM was seeing. One thing we noticed immediately was that we had 0 psi of injection control pressure. This is important to note because most systems even with a major leak or failed IPR valve with build SOME injection pressure. Normally if you don’t see any ICP (Injection control pressure) there is a low pressure oil problem. We verified this by checking for oil in the high pressure oil pump reservoir. In the picture before I got off a Ford forum you can see the allen-head plug that you remove and then stick a screwdriver in the hole and oil should be filling it up to around 1/2 inch from the top. On this truck it was completely empty.
After seeing the reservoir empty, we cranked on the engine for a few minutes and no oil ever came into the reservoir. This indicated that the low pressure oil pump was not functioning. We decided we needed to tear down the front of the engine to check out the pump.
The LPOP (low pressure oil pump) on a 7.3l Powerstroke sits on the crankshaft behind the harmonic balancer. As the crankshaft turns, the gears turn within themselves and this motion creates a film of oil that then picks up from the oil pump and is distributed throughout the engine. This film of oil that creates suction and pressure is very crucial to the operation of the oil pump.
On the 7.3 Powerstroke this oil pump CAN be installed incorrectly which is what I was thinking when they had just rebuilt the engine and installed a new pump. After removing the oil pump we did in fact verify that it was installed backwards. In the picture above you will note the word damper. This word should face toward the damper or the harmonic balancer and they had installed it facing toward the engine.
When the pump is installed backwards on this engine it “eats” a groove in the timing cover that makes it impossible to build up oil pressure again. In the below picture you will see a sizeable groove worn in the front cover. This kind of damage is irreparable.
To fix this costly mistake we had to replace the front timing cover and oil pump.
If you have a Powerstroke that is having trouble building oil pressure the LPOP is a good place to start and if you have any questions call me at 706-677-0060. Thanks, AJ