After reading a few posts recently about possibly extending oil change intervals, pushing the limits on fuel filter changes, and possibly using "will-fit" filters, I thought that I would re-post this article on the 6.0L HEUI system.

Hope it helps explain why most folks on this forum insist on advocating clean fuel, clean oil, OEM style filters, etc. Seems like lots of new members since last year, hope it helps ya'll too ..................................


Below is a good write up on the Powerstroke Injector system (HEUI) w/ the same advice the great resources on this site give regarding filtration and proper fuel and oil care. Nothing real new here if you have been on this forum for a while, but the article just sums it up nicely.

Hydraulically-actuated, Electronically-controlled Unit Injectors (or HEUI injectors for short) will have a tremendous impact for the good, or not so good, for the foreseeable future.

PowerStroke diesel and Caterpillar powered RV vehicles depend on HEUI systems to deliver the fuel and make these engines run. The HEUI design uses a second high-pressure oil pump and delivers a constant flow of very high-pressure motor oil to gallery passages in each cylinder head. (Pressures between 500 and 3000 psi) When the electric solenoid on top of a HEUI injector is actuated, this high pressure oil is directed into a chamber inside the injector and provides the hydraulic pressure to force an intensifier piston to move downward. The intensifier piston in turn pushes fuel out into the cylinder. Fuel is injected into the cylinder at pressures as high as 21,000 pounds per square inch.

The technology described here is really quite amazing. It permits fuel control that is so precise that, combined with the rest of the system, cylinder performance can be monitored and instructions to each injector modified to make a smooth running engine even when other mechanical factors would make other engines run rough.

Priced in the neighborhood of $300 per injector, a set of 8 injectors along with the labor to change them can cost more than we used to pay for a complete engine 15 years ago. These injectors depend totally on clean oil of high quality, clean fuel and fuel with enough lubrication ability to make pumps and nozzles have a long, dependable service life.

PowerStroke engines pump unfiltered oil from the sump to the high-pressure oil pump and then to the injectors. This means that to not change oil or to do anything that contributes to accumulation of dirt in the engine will subject your expensive injectors to wear and potential damage as particles suspended in the oil get forced into the injectors.

Because the injection system uses unfiltered oil directly from the pan , it makes total sense to use the very best synthetic motor oil after break-in. High quality synthetic lubricants can tolerate much higher temperatures without coking or breaking down. The best synthetic oils also keep the engine clean by being able to dissolve deposits and keep them safely in suspension to be filtered out or removed at drain time. It is a good idea to install a bypass oil filter on these engines. A fine bypass filter slowly filters the oil to remove particles as small as 2 microns. The full flow filter lets particles below 20 to 30 microns stay in the oil. It is the particles between 5 and 30 microns that are responsible for most of the wear on HEUI injectors and engines. Adding bypass oil filtration, in addition to the normal full flow oil filter, will get rid of these small particles, which would otherwise accumulate in the motor oil to become the cause of wear and failures.

Oil is important to HEUI systems but fuel is equally important. The lower section of a HEUI injector is lubricated by fuel. Dirty fuel means injector wear. Changes in our fuel to help the environment have resulted in the fuel we buy being a poor lubricant compared to the fuel of 10 years ago. You need to use a top quality fuel additive in every tank of fuel if you want to get the best life out of your HEUI fuel system components. You also need to stay on top of fuel filter maintenance. Make very sure to use only filters from Racor, Parker, Ford or Navistar, as there are inferior filters available that suffer from torn seals and let dirt into your injection system.

Another fact about HEUI injectors is that they rely on o-rings to keep fuel and oil from mixing or escaping from their proper flow paths and causing performance problems or engine damage. HEUI injectors use 5 o-rings. The 3 external ones have been the subject of a great deal of trouble and do need to be replaced with updated o-rings if they fail. The 2 internal o-rings are not field replaceable. If these fail then the injector or injectors must be replaced. While HEUI systems are inherently reliable if properly maintained they present some diagnostic challenges when injector hydraulics are not working properly. It is often possible to tell which head has a pressure leak but the only way to prove the cause of the leak is a process of elimination. You can change the external o-rings and see if this fixes the symptom. If external o-rings do not fix the symptom then you either have an internal o-ring problem or a leak in the head itself, like a casting crack. You prove which cause is at fault by replacing the injectors in question. If this doesn’t fix the symptom then you have a bad head or heads.

The most common symptoms of injector o-ring trouble are oil getting in the fuel, the fuel filter element turning black, long cranking times before starting, sluggish performance and reduction in power. Increased oil consumption often accompanies oring problems or any fault that lets fuel in the oil.

Any money that was saved by ignoring or neglecting needed maintenance on lower mileage vehicles comes no where near being worth the pain of parting with thousands of dollars for fuel system repairs that could have been avoided.

 

not a bad idea!! this should be a disclaimer to new users! lol

 

Good article. Only one quibble: "PowerStroke engines pump unfiltered oil from the sump to the high-pressure oil pump and then to the injectors."

The oil in the HPOP reservoir comes straight from the oil filter. It doesn't come "from the pan" like the next paragraph says. It's as clean as it's gonna get.

 

I noticed that as well. I've seen many statements that the oil is unfiltered, but if you look a the 6.0L oil system, it comes from the filter to the reservoir, which supplies the HPOP. Maybe the earlier models were different.

Mark, good write up and info, thanks!

Mark

 

Good stuff!! As newbie diesel owner, this really helps me better understand the internal workings of the engine. Thanks!

 

Hey thanks Moebdick I was always under the impression that the oil to the HPOP was unfiltered so I guess now I will look that up.

 

the only thing there that scares me is, the long cranking times. WTF, is long?

 

I also had always heard it was unfiltered oil (not just from the article I quoted but from several sources). Never bothered to challenge it. I certainly appreciate the corrections. I am curious now how this information began????

Regarding the long crank times, I have never experienced crank times over 2 seconds. I do use synthetic 5W40 and I believe it helps. I do have the benefit that it doesn't get much below 30 degrees here.

 

I don't know. Where'd you find it? It halfway sounds a little like an infomercial for bypass filters and synthetic oil.

Mine never used to crank much over a second or so before cold starting. With every winter I notice that it takes it a little longer. I'm guessing as the fuel injector spool valves get planished with age, they don't work as well when they're cold.

 

I went back to the source of the article postedhttp://www.thepowershop.com/powerblog/?p=69)

The article now has a note at the bottom:

Please note the publication date of these articles. The information was correct at the time of publication but may not specifically apply to vehicles produced after the publication date. We are working hard to update the older articles to contain information about newer vehicles as appropriate. Thank you for your patience ~ The PowerShop

The article was published in 2000. Note in the second paragraph (italics) of the article it specifically references powerstroke engines in RV's (too early for our trucks).

Again - good catch Moebdick . All else should be applicable to our 6.0's.

 

It wasn't even correct when they published it.

 

the fuel lubricity is not nearly as big an issue as he thinks either. fuel PRESSURE however is, just like any engine it doesn't matter how good your oil is if you don't have ENOUGH pressure you will suffer a failure. the only thing that returns the injector plungers for the next injection cycle is fuel pressure if your fuel press drops below about 40psi your going to have injector failures additives or not

 

While your advice on fuel pressure is a very good point to add on to the article, I disagree with a couple of your other statements.

First, the lubrication properties of ULSD is a problem, that is why it is crucial that the distributor add chemicals to restore lubricity. I do not think the article writer over emphasized the point at all. It is especially a problem IF the fuel distributor does not add the proper additives or forgets to add them at all. Even if they do add them in the proper proportion, the lubrication is improved when we add the proper fuel treatment additive in each fill up. The article simply states "to get the best life out of your HEUI system - use an additive and use the proper filters". This is clearly important. In addition to poor fuel additive packages from the distributor, moisture and other contaminants far too frequently get into service station fuel tanks. Proper filters, filter maintenance and additives are a big help (water removal, corrosion protection, gelling protection - a big problem with fuel pressure is when the filter clogs from gelling).

Also, it is really the oil flow that lubricates and protects. Oil pressure is used as an indication that the pumping system is working. Proper flow is "inferred" with proper pressure. This is a problem on winter start-ups when too heavy an oil is used. You will get oil pressure before you get proper flow. If you live in a VERY cold climate, an oil pan heater AND proper oil weight contribute to improved engine lubrication on start up. On start-up, you get far more corrosive vapors generated. The oil additive packages are designed to neutralize this "low pH" result of poor initial combustion and moisture. It can not fully do so until proper flow is established. The sooner you get flow, the more engine life you will have. Who knows how much life you add on, but with the cost of these trucks, my plans are 500,000. Idling for a few minutes before "taking off" is very advisable - just do not idle for too long without the high-idle mod. I believe that we will soon see Ford recommending year round use of 5W40 synthetic (since they are now selling one) for this very reason PLUS a few others.

The article clearly missed the boat (as I did also) with the unfiltered oil portion. It also emphasizes oil bypass filtration (which I haven't put real high on my personal mod list). Even so, clearly oil bypass filtration helps. Proper systems do remove particles that the full flow filter does not remove. They help - how much help is certainly up for debate. Using the proper OEM style oil filter is clearly more important than the extra help from a bypass filter.

There is much good advice contained in the article. The main point of my post was to address the fact that there have been MANY posts recently directed at using will-fit filters, extending filter change intervals because it is cheaper (short term), fuel gelling problems, EXPENSIVE injector problems, etc. Taking precautions in these areas is SOUND ADVICE.

 

I have always been a firm believer in the fact that synthetic oil is just BETTER! so I have run it in my rig since my second oil change which I believe was at 6,000miles...and I have always run an additive in my fuel, ALWAYS I can honestly say I dont think I have ever forgot to pu it in! I have recently started running bio since its readily available to me down the street and it seems to me the benifits of running bio out way the added cost of it(its 0.30 more a gallon)and the truck is much quieter and definetly runs much smooother!what I dont understand is if you luv you rig then why dont you take care of it lik its supposed to.....I guess im just venting here a littlenot having problems is worth spending the extra dough in my mind!

 

For the record we have accumulated a combined 660,000 miles burning LSD and ULSD on 11 engines with HEUI fuel systems, we do not have bypass oil filters, have never used fuel additives and have never replaced even one fuel injector.
At an average mpg of about 8, thats 82,500 gallons of diesel fuel or about 3300 twenty five gallon fill ups. If we poured in a $4.00 bottle of additive every 25 gallon fuel up we would have spent $13,200 just on additives.