Hey folks, I've got a cool weather start / run issue that's got me totally stumped: it's on my D3K (LLL00176) with a C4.4 ACERT in it (C4E00919), and is having trouble starting in cool weather, anything under roughly 50F or so. Here's a short video showing some start attempts: https://www.youtube.com/shorts/b4Qn8e1yStw Some additional information: Starts and runs great if the engine is already warm If it does decide to start, before it warms up, it runs poorly even when throttled up, huffing and puffing, sometimes even running for a whole minute and then dying (governor issue?) Replaced coolant temp sensor Replaced air intake manifold temp sensor Replaced alternator Batteries are only 2 years old and at full charge via external charger Cleaned and re-seated all electrical connectors Replaced fuel filter Replaced water separator Brand new fuel in it, including HEET additive Tried putting Diesel 911 in fuel filter (50/50), which did result in engine firing up a single time, but did not alleviate issue Once the engine is warm it runs great - I ran it for 6 hours or so without issue one day, but once it cools down the next day it's back to square one Ether has zero effect And now here's a short video showing how well it starts up when I disconnect the return line to the fuel pump, which is very confusing to me: https://www.youtube.com/watch?v=1md_R4Uw8ZQ Any insight anyone can offer would be greatly appreciated.
How many total hours are on the tractor.? Your tractor engine is equipped with glow plugs. Are they working.? Your text above makes no mention. Even if the warning light comes on it may be worth testing each plug to ensure that they are all firing. The second video suggests that you might want to look at the rail pressure relief valve. C4.4 engine fuel systems are famous for starting issues. The usual fix is to throw a rail pressure relief valve at it. if that doesn't work then a set of injectors, and failing that a replacement HP fuel pump. The above is usually a consequence of inadequate fuel system maintenance to prevent water & sediment from the tank getting to the expensive parts of the fuel injeciton system.
Thank you very much for responding! There are 6300 hours on the machine. Regarding the glow plugs, they have not been turning on (based on the lack of an indicator light) - however, as of this morning (32F temp outside), for the first time ever they actually did turn on after I hit the starter, and remained on for a good 10-15 seconds, even after the engine fired and I cut the starter. This was the first time it's ever started up with ease in the cold. Perhaps replacing the coolant temp sensor yesterday played a factor there. Still, the machine had a very rough time idling, but did technically start up on the first try and ran for a few minutes. During this warmup when it was running rough, it did briefly throw a 398-2 error (Low Fuel Rail Pressure) and die out, but upon restarting the error was not there and the engine was able to run long enough to warm up. Once warmed up, it's now running great, even at low idle. Given that it runs great when the engine is warm, do you still think the issues are related to the relief valve / injector / high pressure pump?
Starting problems when cold on a C4.4 are usually the first sign of trouble. The way the symptoms develop from what you have right now is that the engine will begin to have starting issues when it is semi-warmed up, then when it is at normal operating temperature. Eventually it will reach the point where it won't start at all. Have you owned it from new.? Because with 6300 hours it's probably getting ready for all the parts I mentioned above, most likely sooner rather than later. The glow plugs are controlled from the Engine ECM, but I can't find details on exactly what the strategy is. I would imagine it is dependent on inputs from the sensors for both intake manifold and engine coolant temperature. According to the Operation & Maintenance Manual, which I take it you don't have, is the advice "Turn the governor control knob approximately one-third of its travel. If the machine is cold, wait until the glow plug indicator light turns off. Then turn the key start switch to the START position."
Ok, that's all great to know - thank you. I purchased the machine used 20 or so working hours ago, but only saw the symptoms once the temperatures dropped in the late fall. Would you recommend just replacing all 3 of the fuel items at once? My worry in doing them one by one gradually is that if there's corrosion in the fuel pump and I only replace the relief valve & injectors, then they'd just get wrecked in short order again as the junk from the fuel pump made its way in, but perhaps I'm over thinking that. The glow plugs still didn't work as I'm used to on other diesels: the glow plugs did not turn on when I turned the key on, rather they only turned on once I started cranking the engine over.
I understand your dilemma but I would suggest that you get prices for the parts first before making a decision. Just make sure you are sitting down when you ask. As a first step maybe you need to be ensuring that the fuel system is clean, starting at the tank and working forward. I would imagine the water & sediment has not been drained out of it in a while.
Good call on the fuel tank and lines - I'll get that cleaned out today. Regarding the replacement of injectors, I've done it once before on my Bobcat track loader, but had a service manual to give all me all the details (Bobcat only charged $60 or so for it; Cat charges $1100 or so for the D3K service manual, so I've not gotten it yet). Anyways, is there any chance you've got access to those instructions & torque specs and would be willing to post them? Thank you.
If you get round to replacing parts I'll see what I can dig up. One thing you need to be aware of is that both the injector hold-down bolts (Torx) and the high-pressure fuel injection lines are single-use only. When replacing injectors they also have to be replaced.
Here is a used copy on eBay for about half that.
I should also have mentioned that a complete copy of the Service Manual will also include a copy of the Operation & Maintainence Manual, which would sell separately for around $75. A question to ask the seller of the link I posted above. The 4th photo in the listing is the Index page. Are all the various modules listed in that page actually present in the manual he is selling.?
Make sure whatever starting aids your dozer has are working properly and use them per the instructions in the operators manual. Cold weather is the Achilles heel of diesel engines. Diesels initiate combustion via the compression of the air fuel mixture. In cold weather, the peak compression temperature is lower, the cold cylinder walls act as a deactivation source for the fuel air mixture, the oil viscosity at cold temperatures means that the starting torque to crank the engine is greater while at the same time, the battery output is lowered by cold temperature. Further if you are unlucky enough to have summer fuel in your machine and the temperatures are below ~ freezing, the fuel can gel. You said that you treated the fuel with Heet. Heet is mainly alcohol and alcohol is hygroscopic, i.e. it attracts water. Use fuel treatments that are blended for diesel fuels and try to buy winter diesel for winter operation. Common starting aids are glow plugs, intake air heater elements, and block heater that warm the engine coolant. I don't like to recommend the use of ether or starting fluid because using too much can break piston rings and piston lands. Block heaters are my favorite because they warm the cylinder walls reducing deactivation of the combustion reaction, they reduce the oil viscosity and thus reduce starter toque and current flow required from the battery. You are basically starting a warmed-up engine. The lube oil gets flowing quicker and the start-ups are smoother. As far as the rough running for a cold diesel, you say it only does it for a minute. This is very common for starting without a block heater and doesn't indicate a problem. However, in my opinion, these kind of starts are hard on any engine because oil flow due to cold oil with its higher viscosity is greatly reduced. Foe whatever it's worth thems my suggestions for cold weather starting.
Thank you for your help, everyone! To tie a bow on this thread: I ended up deciding to take it to the Cat dealer. To get it onto the trailer, I knew I needed to get the engine warm enough to start, so I removed the banjo bolt of the injector return line (see my previous post on why this is significant) and used a form-a-funnel to channel the diesel to a bucket - this allowed me to get the machine long enough to get the coolant temp up to 115 or so, and then at that point I put the banjo bolt back in and was able to get it started and loaded onto the trailer. The Cat mechanic found that the fuel pump was leaking fuel into the electrical connector, which they took as an indication that the fuel pump was at fault. They did check the injector leak rate, which was within the normal range, checked fuel bleed back, injector pump timing, air intrusion into the fuel system, and voltage to the ECM. The mechanic did need to reach out to "Technical", which seems to be technical support for mechanics at the corporate level, who indicated that they have seen a notable number of high pressure injection pump failures on this engine. Upon replacing the fuel pump (6 grand later), the machine runs perfectly.
Now that it runs good and I imagine the glow plugs work throw away the ether! Ether and glow plugs can result in a much bigger bill than $6000. It could destroy the engine.