You just can't have enough fuel filter change stories, DSDP 3126E CAT

[dbywaters]

Warning, a bunch of technical stuff, some mild humor..normal day for someone that just can't leave good enough alone
4/18/2016

Oh boy what a day I have had...Started out changing the Air Brake dryer filter on this fancy motor home..yea I know some folks take there stuff to a shop but I don't have shop money and I don't trust them in the first place.
Anyway, the air drier ($150 in parts...supposed to be done every three years...mine...original to coach circa 2003) and this little maintenance item went well taking about 1.5 hours.. I took my time and made numerous trips to the tool box.... counted each one as a set-up..and the short walk as cardio so then I decided to replace the single Fuel filter on my 2003 Dutch Star with 3126E diesel. Oh what a Pain the but that turned out to be....

I screwed off the filter, filled the new one and put it back on just like the instructions and everyone on the internet claims is the way it is to be done.... it started and immediately turned off.. SO after almost 8 hours of cranking, draining and other heroic efforts to push air out the lines from the tank to the engine I found that my coach (with 99% probability) had a loose fuel line at the suction of the Caterpillar HEIU (Hydraulic, electronic, Unit, Injector) pump. For the technically challenged, the HEIU is the carburetor /fuel pump of this diesel engine.. Now for the rest of the story..

Let me share this, this CAT engine is crammed in the chassis, then Newmar made the best of EVERY stinking inch of space around it... To say space is limited is a understatement. (Except where there ain't a dang thing to work on ... in those places you can have a picnic. Thank GOD for a Cell phone with Video and Camera. I'd stick that thing in the hole recording a video then pull it out and review said video before BLINDLY reaching in (while on a step ladder) with a wrench trying to find the HEIU suction line that connects to the fuel filter (BTW, the filter is in a great place, even a fat man can change it easily..) also, FWI, I set at a desk all day and weight a buffet visit shy of 300 pounds.. being fit is is limited to the ability to walk into a restaurant.

You see, I tried contorting my arms, legs, head and tummy for over 4 hours of cranking and walking back and forth the back of the bus to the front before I started searching the internet. I ran across a thread that mentioned pressurizing the fuel tank... Oh yea that's the ticket!

Prior to said pressurization I did noticed the original filter sucked when I pulled it off.. I did fill the new one with ATF prior to re-installing per so many recommendations.. so I did what I was supposed to..I even read that I should tilt the coach up hill which should allow the fuel to run down hill to the filter...so I used the leveling jacks and hiked the front end off the ground..that did not work so then I had to put pressure in the fuel tank..now here are a few notes on the fuel tank...

My wife and I have several vacuum cleaners most only suck but we have one that blows... our RAINBOW vacuum ( which we we still love after 20+ years) is a great blower... and the hose hooks up to the blowing outlet which is a big plus.. SO I sneak it out of the house and with the help of a shop rag stick the hose that normally sucks into the fuel fill. Sealed it up with a rag and I then turn on the Rainbow...it worked like a champ. I heard the fuel tank go boom.. which told me it was expanding as it should, then I visited the new fuel filter and it spewed fuel like it should, I cracked the line going to the engine at the filter and more air! GREAT I am on my way... well it still did not start. Now here is the fun part... As I passed by the vacuum..converted to blower I decided to just pull the hose out of the tank without turning off the vacuum-now blower while I re-grouped..BAD IDEA... you see.. I have over 1/2 tank of fuel which I now presume the fill tube is near if not below the half way level of fuel in the tank..when I pulled that hose out I was baptized with #2 Fuel oil..(as was the rainbow) I was SO drenched I had to remove my shirt..it was soaked, but unscathed I proceeded to my roost on the ladder behind the engine to learn where the hell that HEUI suction line was.. but fortunately the little lady called me in for supper.. So I then showered, ate and searched the internet more.

I found that the HEUI High pressure fuel line is easily accessed where it enters the cylinder head and that I should loosen that connection to allow fuel to be sucked easily and now discharged out of my now un restricted plumbing connection high pressure connection.. So after supper I loosened that line to learn if this little trick would work for Dougie.. but alas the stinking thing was dry as a bone after a couple 30 second cranks. So Then I decided I really needed to contort myself to access the HEUI pump suction line connection of said pump. After cutting a perfectly good 3/4 inch wrench in half I found the line was loose.. and I did not loosen it.. So I rigged up rainbow (again) to give Newmar another blow job and in no time I had fuel spilling out of the suction line connection at the pump... and I kept it spilling until I finished tightening the line.. when tightened, I cranked again and I had fuel at the loosened high pressure port ( just like I was supposed to)... and even with this line loosened she started. Then I tightened the high pressure line and it started even better. (I also leaned that if turned off the vacuum cleaner motor before removing the hose from the filler neck that fuel did not gush out). It only took about 8 hours to get to this point..

Now that I am all buttoned up and she starts like she should things are starting to come together. Ever since we bought this coach in February the engine would change speed (speed up) after first starting and change pitch a couple times.. from quiet to noisy.. I thought this was normal.... but now I believe this noise and erratic RPM's was the HUEI pump clearing air out of the line each time I started it. Now when it starts I get a initial loud diesel noise (advanced timing) and she immediately quiets down, there is no more RPM hunting, 749 RPM cold, solid as a rock. I am anxious to learn if the probable suction air leak had an affect on performance too...it almost has to since it was certainly sucking some air all the time. Anyway.. its all back together now, I have some salve for my sore spots and a Caterpillar that sounds like an old Ford Powerstoke when she starts. I guess it's all good, I learned something and I hope you do too.. but I got to clean that dang vacuum cleaner.. it smells awful...

[Rotten-Red]

Aren't you glad you don't have to do this for a living! That desk is going to look good tomorrow.

I do all my own work also. But I'm sure glad all I have to maintain is my own equipment.

[PDR John]

Just think; If it went easy, you wouldn't have a great story.

[Farmer Steve]

I've run a lot of diesels dry in my day but never used the wife's vacuum for a pressurizer! I hear ya about a tight compartment. I had to tighten a hose clamp on our new dp that drained us down to a warming light. Double jointed would come in handy!

["007"]

For all your hard work and good write up I will add thread to the chassis
QT's # 3 section, hope you had a cool one after your hard work.

[dbywaters]

The only thing I wanted after this was a good nights rest... I also wrote a post about the Radiator modification... I look to gain considerable benefit from that one too..no more dust blasts.

["007"]

I hear you Doug, my 82 year old body has been crawling under my coach for its next long trip, the body does not function to well any more in fact the aches knock me out every night.

[DJJ]

Doug, enjoyed reading your post. Now that you have found the loose line you should not have a problem when changing the fuel filter in the future. Since I don't have a priming pump either I pre fill the filter with fuel.


Jeff
2003 Dutch Star, 3126B Cat.

[dbywaters]

The photo below is my solution for future filter changes. I still have a frame mounted filter that now acts as a pre-filter, it has a water drain on it and is a 10 micron filter (it should grab the big stuff)
I had to change the discharge fitting to a barbed fitting, I connected a new 3/8 line from the fitting to the inlet of the the new filter mount shown below. The discharge of this filter (a 3 micron filter) is looped to a primer pump (available on eBay) shown above the filter, from here the fuel is sucked into the HEUI lift (low pressure) pump. I re-used the existing line on the this section of fuel line due to the difficulty of removing the line from the injector pump. An added benefit of the primer pump is the ability to quickly check to see if there is an air leak on the suction of the pump. Ever since installing this after acquiring a prime it takes a fair amount of effort to push the plunger to pump fuel. BTW, I had to build the bracket for the filter mount and it should be obvious that this secondary filter is easily accessed from the engine hatch.

[Mr_D]

After having two Dutch Star DP's (2000 3865/FL & 2002 4090/Spartan) I can say that Newmar is no where as good as Country Coach at cramming the engine bay full of stuff! Even with a side radiator I still can hardly see the oil or coolant filter from the back.

[Dtwallace]

The only thing better than that added hand primer pump is an electric high presure fuel pump.

Faster, less work involved when changing out the filter, and a reliable way to check for leaks at any time during operation.

The addition of the electric pump is also like an emergency backup when we just happen to run into a filter partial blockage issue on the road. You will not be stranded on the side of the road by a blocked filter killing the engine completing, but will have time to recognize decreased performance with the extra help form that pump and getting to a safe area to change out the filter and no need to prefill the filter, just turn on the switch and drive on.

[dbywaters]

I used an electric fuel pump on my prior coach and it failed. It was an electronic version (it operated like a solenoid, similar the OEM lift pump used on GM trucks in the 80's and early 90's). It was a bad choice for the application. I chose it because it was not as expensive as other pumps (that would probably not had failed)

The failure in my electronic pump was internal, the pumping plunger inside would stick in the stroked position.. literally blocking fuel. It took a couple of stops (starving for fuel) before I learned what was going on. Diesel Lift pumps circulate a considerable amount of fuel (in some cases to cool the injector pum) and most of the fuel returns to the tank via a bypass line or in my case a pressure regulated relief connection located on the back of the head of my CAT 3126. Any old electric fuel pump will not work as it needs provision to allow fuel to be pulled through the pump in case it fails or turns off.

The hand operated pump is Doug proof, and the more things I keep that way the better off I am.

[Sky_Boss]

I thought I have read that there are 2 fuel filters but one is so well hidden it is easily overlooked? I read an account by another user about that once.

[Skip426]

Doug, re your question about the fuel line , the mechanical fuel pump section of the HUEI, draws fuel from the tank , then supplies the fuel to the cylinder head at 65PSI.? and the pressure side has special fittings not just fuel line clamps, so if it's just clamped it's the suction side.
Cat and Powerstroke use the same fuel delivery system hence the common sound.
Re, your complaint about access to the engine , that just makes me so happy my DW didn't like the coach we saw ( at the dealer where we bought this one) that had a bedroom slide. Biggest access problem I've had was replacement of the compressor oil pressure supply line from the side of the block to the compressor , that required removal of the hydraulic pump. Can't blame Newmar for that one.