Trusted Contributor

Re: 416D backhoe not running right - unusual and sporadic

Hello again JB.

 Your 416D is a later version so, the engine in your machine is a Caterpillar 4054, it has a slightly different engine and fuel system than the earlier models with a Perkins 4-236..

  Anyway, the test for air in the fuel supply is still valid, in fact that test is a good test for any diesel engine, even recent ones.The rubber hose part of the fuel supply line is a source of air entry, if the steel line rubs against any other part it is also suspect. If there is dirt gathering along any part of the fuel system, that area is suspect. I would strongly advise to test for air enrty before replacing anything because you need to know EXACTLY where the problem is. There are other possibilities but solutions are much more involved. Troubleshooting is a process where you go, one step at a time..

  The electric fuel lift pump is also suspect, you could test it by loosening the line from the filter base to the rear of the fuel injection pump. With the engine running, there should be some pressure in that line. If no pressure, there could be afailed fuse or the pum itself has failed. There should be an owner's manual attached to the operator's station with a lanyard, there will be a page with the outlay of the fuse panel.

  The piece of a screen rolling around in the tank bothers me so, I would investigate. I haven't worked on any part of the fuel tank. If there is a fuel level gauge on the machine dashboard then the fuel pickup tube and the level gauge sender will be attached to a plate bolted to the top of the fuel tank.

  Your machine will not have a glow plug as I described, they are used on the Perkins 4-236 engine.

  I'll leave you to it.




Re: 416D backhoe not running right - unusual and sporadic

I am very thankful that you are willing to share so much knowledge with others.  That really is a wonderful thing.  It seems that there are quite a few versions of the fuel systems on these 416D backhoes, so I thought I would explain mine to shed some more light on the topic.  The supply and the return lines attached to my fuel tank are steel tubing.  After this tubing runs inside the engine compartment, it changes to rubber hose.  The supply hose goes to the fuel filter block.  This is the only fuel filter.  There is no secondary.  The fuel filter block appears to have a black plastic fuel supply pump attached on top that is run electrically.  The fuel from there goes to a nipple on top of the fuel injection pump that is run by a gear off the engine.  The fuel filter and the injection pump are on the drivers left hand side of the engine (same side as the fuel tank).  The fuel pumped from the injection pump goes via metal tubing up to the injectors.  There seems to be some fuel soaked dirt built up on the rubber hoses down by the fuel filter, and since it is winter here (10 degree nights), I don't want to wash the hoses off just yet for inspection.  I am thinking of cleaning and replacing all rubber hoses before performing the tests that you outline, so thank you for sticking with this post.  All that said, I did drain some fuel out of the filter and caught it in a clear jar.  There was some black grit on th bottom of the jar and a magnet proved this to be iron oxide.  I inspected the inside of the tank and found a round screen rolling around the bottom, as well as the guts from several old fuel caps that had broken off and fallen down in (vandalism...?).  Anyhow, the tank bottom looks shiny and clean, but I want to fully inspect the inside for other junk and to replace the strainer onto the fuel pickup line.  Is the best way to do that to unbolt and remove the fuel spout that the gas cap attaches to ?


Thanks much,



Trusted Contributor

Re: 416D backhoe not running right - unusual and sporadic

Hello again,

  After reading my post regarding you 416 problems I realised that I did not properly make the connection between the Perkins glow plug  and your problems with erratic engine problems.

  If the tiny fuel valve of the glow plug assembly does not close properly, a couple of things can happen. The fuel line to the glow plug comes from the fuel filter base, supply side. Anything open, on the fuel supply side will allow air to enter the fuel stream while the engine is running. Since the fuel lift pump only produces 4-5 psi to the FI pump inlet, the tubocharging system can produce more manifold boost than 4-5 psi, air from the pressurised manifold will enter the fuel stream. FI pumps do not pump air very well, the FI pump will stop functioning and the engine will stop.

  If the engine has been running and is shut off, fuel from the filtering system will have been under lift pump pressure 4-5 psi. When the engine stops, the time it takes, for the lift pump pressure to dissipate, is enough to cause fuel to dribble into the manifold, then into one or more cylinders. When the engine is started again, the fuel in the cylinders will cause the engine to run erratically, smoke more than normal for a few seconds, sometimes the engine will race uncontrollably for a few seconds.

  To conclude, you may have one or more of the problems outlined, you may have none. These are some of the things I haveencountered in 40 years at the trade.

Trusted Contributor

Re: 416D backhoe not running right - unusual and sporadic

I have responded to quite a few people with similar problems. There are some basic things to test, not hard to do. I am surprised that a Caterpillar dealer couldn't find the source of your problem.

   The fuel system needs a good supply of fuel with minimum negative pressure (vacuum) and no foam or air entrained. In addition the fuel injection pump's transfer pump will supply more fuel to the high pressure part of the pump than is required by the engine under maximum load. The quantity not used keeps the injection pump cool and is returned to the tank.

   The first test is to remove the fuel return line at the tank and submerge the open end in a pail of fuel, then, start the engine. Watch the fuel returning to the pail, #1, is there flow and #2 are there air bubbles showing after an initial burst? If there is flow then the supply system is ok, no flow would indicate a supply system restriction. If there are bubbles in the return then the cause of this needs to be found. Before much further I would substitute the supply system by connecting the fuel inlet at the injection to a pail of CLEAN fuel then retesting, comparing the results. By now you should have a good idea what to fix.

  The Perkins engine in the 416 may have a starting aid, a glow plug in the intake manifold. If your machine has one, how it works is, there is an electric glow plug but, there is also a small line from the secondary fuel filter which supplies fuel to this glow plug. There is a tiny fuel valve controlled by the glow plug heat.  So, what happens when you select the glow plug feature is the glow plug glows red hot, the fuel valve opens, a tiny amount of fuel flows in and actually starts a fire in the manifold. This fire is what heats the incoming air to the cylinders when the engine is cranked to start. All the foregoing blather is mentioned because, if you test for air in your fuel return, that goes away when using the substitute supply, the glow plug may be the culprit. BTW the Perkins glow plug is not commonly understood, by techs.

  One other thing that must be pointed out is that, the injection pump may have been built with a plastic ring called a weight retainer ring. This plastic ring couples the governor weight cage to the drive plate and gives some deadening to the drive. Over time, the plastic ring deteriorates into stuff that looks like coffee grounds and is returned to the fuel tank thru the return fitting on the top of the FI pump. If the coffee ground material gets thru the return fitting, the FI pump will continue to run for some time. However, if the coffee ground looking plastic debria lodges in the return fitting the FI pump will stop functioning and the engine will power down and stop. One easy test for this is to remove the small cover on the side of the FI pump, making sure area and all tools are CLEAN. If the weight retainer ring is failing, coffee ground like material will be visible under the small cover. As I said, if you see evidence of a failing weight retainer ring, the FI pump must be removed and reconditioned. Stanadyne introduced and update for the retainer ring some years ago.

  I hope all this is ome help to you.. Best of luck..


New member

Re: 416D backhoe not running right - unusual and sporadic

My backhoe done something similar to this a couple years ago. Found water in the tank and thought I had fixed it ran real good in the yard but would not run down the road unless it was warmed up forever. After chasing my tail forever it ended up being the injector pump had a couple bad seals in it. Found a kit on ebay or amazon for under $30 and replaced them all. Runs like a champ ever since.  I am guessing it was warming up pump enough to expand things so it ran better once warm. I was very leary about the pump rebuild before I done it. I figured it was some extravagant bunch of magic parts that required sacraficing 3 goats and having 12 engineers on standby to do, however it was pretty simple to replace all the seals and get it back going.


If you can get a pressure tester from a friend or maybe rent one from an auto parts store you can check all your pressures pretty easy to find or eliminate this as the culprit.


416D backhoe not running right - unusual and sporadic

I have owned a Cat 416-D for three years now. Sometimes it runs well and other times poorly. I have changed fuel filters a dozen times, cleaned the fuel tank vent, replaced the air filter, drained the tank looking for debris etc. I found a few old gas cap parts in the tank and a small tubular screen that looks like it should be over the fuel intake tube. The machine runs well at idle and it also runs well when hot (after 1/2 an hour). In between, it often stalls out or dies. During this time, I can put the pedal to the floor and it will not respond and will slowly die (sometimes), but at other times it will slowly ramp up in RPM. This behavior is on and off. I have drained some fuel out of the bottom of the fuel filter and found some little black specs that were attracted to a magnet (rust...?) but the inside of the tank looks very clean.

We are a long way from a Cat dealer and the one time I took it there, they couldn't find any problems. Can any of you please help me with tests procedures or ideas?

Kind regards,