Air in deisel fuel line - motor won't start

[retiredhfd]

I changed the fuel filter on my 2002 Fleetwood Excursion and some how got air in the fuel lines. The engine is a Cat 3126 - 330 HP. The motor on my coach has NO primer pump. The fuel lines going to the injectors are all covered. After tearing my coach apart to find all of this out I contacted a mobile diesel mechanic. He restarted my motor in 10 MINUTES. He took off the air cleaner intake duct and while I turned over the motor shot quick start(ether)with WD 40 at the same time into the air intake duct. The motor ran rough at first but after the 3rd attempt the motor was purring like a Cat should. He says the WD 40 added to the quick start adds lubrication to the cylinders . He also said you have to be carful when doing this and make sure the motor is turning over before you begin the spraying. I just thought I would post this just in case someone else has the same problem in the future. Hope it helps.

[Mike_Hohnstein]

Have a electric pusher pump with a check valve plumbed into the line to prevent drain back in all my diesel rigs. The most trouble prone fuel system can profit from this set up. Electric pump is wired through a oil pressure switch with a momentary button feature to facilitate filter changing. The manual pumps work but I'm lazy.

[wolfe10]

Yup, the manual primer pump takes all the DRAMA out of priming the fuel system and is easily retrofit.

IMO is was a stupid decision by the bean counters at the chassis manufacturers to save a few bucks by deleting it or by fitting only a single filter instead of the "correct" primary and secondary fuel filter.

But, all the engine manufacturer requires is that "fuel be filtered to XX microns). It is up to the chassis maker as to how this is achieved.

[cdl2]

I put a manual hand pump on my Cat.
Original system was sucking air.
Nothin better than breaking down at 11PM in Idaho in the middle of nowhere, after giving the mobile diesel repair guy $400.
That was a 3126 Cat.......sold that one

[wolfe10]

dcbrewer wrote:
I always just cracked a line loose at each injector to let the air out. Only when I run out of fuel. Make sure filters are full first.

That works with some diesel engines. Others (newer engines)are designed such that this is not possible/necessary.

[dcbrewer]

I always just cracked a line loose at each injector to let the air out. Only when I run out of fuel. Make sure filters are full first.

[wolfe10]

Excellent solution, Scott.

Brett

[FIRE_UP]

Well Gang and OP,
As many of you on here have seen and read of my post of the same exact situation. You also saw and read of my remedy to this so that it (retraction of fuel, back into the tank, during a filter change)NEVER HAPPENS AGAIN. And my remedy was, install two, shut off valves in the system. One installed before the ONLY filter I have and, the other shut-off valve, installed on the output side of that same filter.

This way, you can shut both of those lines down, right at the filter, unscrew it, take your time in prepping the new one, and install it. Then, open the valves and, absolutely "0" starting troubles from that point on. It's a cheap and easy fix. Well, I say cheap, meaning about $20.00 plus or minus, depending on where you obtain the parts. But, Brett Wolf and I discussed my situation and, he, CAT, and Freightliner all agreed I had to pressurize the fuel tank and lines, all the way to that filter before mine would start.

I still had to pressurize the line from the filter to the lift pump on the back side of the HEUI pump before it would start. So, with my system, I'll never have to do that again.
Scott

[wolfe10]

To expand on Branson's post. Yes, if you want to purge that 30' of air from the tank to primary/only fuel filter, the way to do it (easier with two people) is:

Crack open the outlet to the filter (better)or unscrew the filter just a little.

Have someone using their hand/towel to cover the rest of the fuel fill, add air pressure. You are not going to apply enough pressure to do damage (probably under 5 PSI)-- just enough to force fuel through the line and filter.

When air-free fuel comes out, tighten the connection/install the filter the rest of the way.

From there, it will self prime. Be sure to "rest" the starter between starting attempts.

[Branson_in_Tucs]

Happen to me with 2003 Fleetwood Providence.
easy fix.
I got a air pump that plugs into you car ignition.put it on your fuel tank and wrap with towel.Turn on and had some one start RV engine while air pump was on.
Started right up.

[wolfe10]

No glow plugs, but you DO have an INTAKE MANIFOLD HEATER, just like virtually all larger modern diesel engines. Ether and red hot wire is an explosion waiting to happen (and it won't wait long).

First question: Do you have one fuel filter or two? If two, is the secondary one a Caterpillar filter base? If so, remove the two bolts on the side cover and install a Caterpillar manual primer pump.

And, even if you fill the new filter before installing, if the level of the fuel in the fuel tank is below that of the filter housing base, the fuel will siphon all the way back to the tank, leaving you with 30' of AIR in the fuel line. Kind of tough for any diesel to prime that much!

[mike_brez]

Injectors don't like air. If you have glow plugs best to unplug them before shooting starting fluid in intake.