...so I finally put a handle on an oil leak after it got worse over the years. We bought the Excursion somewhere around 2003+- with 120K+- on the clock. From the get go the truck always threw black smoke when you put your foot on the go pedal hard. I figured it was due to the previous owner driving alot of highway miles from here in south Texas up to Colorado for dirt bike races and it was just blowing some of the built up soot out. I started to notice a slight oil leak later but could never track it down. The oil leak finally got worse the last 25K-30K miles...it now has about 240K on the clock...and I was able to clean everything really good and find the passenger side HPO line loose at the HPOP. The o-ring could be seen squeezing out of the fitting which was just barely over hand tight! I bought and installed the new jic fitting hoses and have been driving it a bit...it's the wife's truck and being a kiddo hauler grocery getter, she somewhat babies it...laying the go pedal on the wood. I've noticed this fix has cleaned up the black smoke when in the throttle. I'm guessing the injectors on the passenger side head weren't getting as much oil pressure as the ones on the drivers side head causing them to not run as efficient. The truck still got 20+ mpg on road trips and ran fine, though it did idle a bit rougher than my F350...just a slight miss you could feel in the seat of the pants and see in the bottled water waves in the dash cup holder. The idle is now smoother after the HPO line install...I did remove those drain back springs in the HPOP. I haven't as of yet...but plan to in the next couple of days...hook up Forscan and do some driving to monitor some things.

So my questions are:
1.) Is my thought about oil pressure differences relative to injector efficiency and black smoke plausible?
2.) Given this has gone on for several years and/or miles; any chance the passenger side injectors suffered?

 

Surely someone on here has some input on this...

 

1 & 2) Not likely, but a possibility.

Once the oil enters the hoses to the heads, they are essentially their own pressure systems separate from each other. Unless you have an HPx or the HPOP check valves have been removed

That said, the HPO may have been a bit less on the passenger side, but the injectors will literally not operate if there is a lack of oil. The oil acts as a hydraulic fluid for the injectors.

Since your wife drives the Excursion with a light foot, the HPOP was probably not operating at 100% (65% IPR DC) or at 3000 PSI (ICP) much.

The ICP would still cause the oil to leak even at idle, as it is still 1000 - 2000 PSI on a regular basis.

Going forward, fluid leaks should be addressed ASAP. I get it... I ran with an oil leak for months and a power steering fluid (ATF) leak for 4 years.

They were drips really though and I ended up fixing them when I could, like you.

Edit: I misread #1, my apologies. Caught my mistake when Brandonpdx posted.

 

1.) Very plausible
2.) If it's running fine now I wouldn't worry about it.

Good catch on that one. If that let go it would have been a tow bill and a real mess under the hood.

 

Thanks guys, I just can't figure out...other than my initial thoughts...how the leak fix would clean up the black smoke. The check valves were still in there...I removed them when installing the new jic lines...and it did not have the cross over line. I'm just thinking the reduced oil pressure was causing the rich condition black smoke from the passenger side bank. I'm glad I was able to catch it when it finally reared its ugly head and it didn't blow either that o-ring the rest of the way out...or worse, the whole fitting out which would have probably required a new HPOP!

 

So, I just ordered some new HPOP hoses with the JIC fittings. Is the crossover line a good idea or not? And, what am I missing about the check valves? Should they be removed or left in place?

 

You do not need or want the crossover line as it's just another leak potential...plus removing the check valve springs accomplishes the same thing.

 

bwguardian nailed it.

The check valves can come out (might have to with the JIC fittings) if you are there anyway. Removing them equalizes the HPO across both heads which is what the crossover/HPx is supposed to do.

 

Nobody around here recommends the crossover line. The check valves I believe were there originally to make the engine start faster/easier.

 

Good to know. The kit came with the crossover hose. Guess it'll go in the tool box with the extra CPS, belt, and other roadside fixin' parts.