Hey all. Long time lurker and first time poster. Have to admit, I have learned a lot from you all over the past years. Thanks to all for the knowledge exchange and sharing. So...here's my latest that I am unable to find any information on, and it has me totally stumped. Cat 277c Skid Loader, serial KCC00096. About a year ago during normal daily operation, I shut the machine off and it would not restart. Let it sit for a while and then it would restart. The problem progressively worsened. Now the machine will crank over, no puffs of smoke from exhaust, indicating it is not getting fuel. If I hit it with just a very small shot of ether, it with start and run normal. Been useing machine like it is, but hate to leave it idleing and putting hours on it for no reason. Here is what I have done. Verified electric primer pump runs and supplies fuel to the injection pump. New fuel filter and checked for water in seperator. Verified fuel shut off solenoid proper operation. Removed, cleaned and checked for obstructions/sticking. Verified voltage to solenoid with key on. So, overall, this should be getting fuel, but indications are that it is not. So, if that is the case, why does it start and run normally with a small shot of ether? I am stumped and would greatly appreciate any ideas or suggestions that anyone may have.
Based on the symptoms you described, it is worth checking the compression in the cylinders, as well as checking or replacing the fuel injector nozzles.
You seem to have hit most of the pertinent parts of the fuel system apart from the tank. Have you ever tried draining it to check for contaimination.? The one other thing I would suggest is to remove the fuel filter/water spearator assembly from the machine and disassemble the head as far as possible then either blow through all the passages with compressed air or rod them out with some stiff wire. Those passages are known to block. You state that "Verified electric primer pump runs and supplies fuel to the injection pump." but that pump is known to have problems. It was replaced by an improved pump. See SEPD1662 attached. Have you removed the air filter elements and taken a look at the intake line to check for dust passing the filter.? That could explain the slow deterioration of hot starting. Does the engine consume oil at all.?
Very possible, that the solenoid for the pump is degrading with heat. Or also the fuel shut off solenoid is doing the same thing. I would start by disconnecting the fuel shut off solenoid and check OHMS hot vs cold.
Thanks to all for the replies and suggestions. To address - Tank has been checked and is clean. All lines and passages clean and free flowing Electric primer/lift pump was one of the first things changed, with no effect. The pump is mounted to the top of the fikter element as a part of the asssembly. During replacement, filter was changed and all pasages cleaned and checked. Shut off solenoind has been OHM tested/verified good. No change from hot to cold. No difference in starting whether machine is hot or cold. Engine intake is clean. No oil burning. No smoke. Fairly low hours machine at 1400 hrs. Compression seems normal although not checked. When running, has normal power comparable to other machines. In the mean time, I do have another idea to check. While I verified voltages at the fuel solenoid with key on, it may be losing voltage in the start position? In this case it would kick off on the ether, and when key is released, fuel solenoind gets voltage and it then runs normally on fuel? Its worth a check. Kinda like the older Mopar products whe one side of the ignition ballast resistor would burn out. I did read something regarding a resistor on the back of the fuse block that may have some effect, but I am unable to relocate the article or part listing. (anyone know anything about this?) I'll be out in the shop in a bit, and will update the diagnostics with my results of testing. If anybody has additional ideas, it would be apprciated! Thanks again to all.
Have you ever adjusted the engine valves?
I have not adjusted the valves. Could you please expand on your idea/reasoning?
Your 277C is scheduled to have its engine valves adjusted every 1000 hours. Unadjusted engine valves are one of the reasons for low compression in the cylinders.
Got it and understood. I'll check them.
Most likely, your engine valves are very tight and have a clearance lower than required.
A suggestion would be to have someone put a meter across the battery terminals (the probes should be dead centre of the + and - terminals). Have them measure the voltage with the ley ON then observe the voltage drop while you are cranking the starter. Post your numbers. While you're at it inspect/clean/tighten all the main battery and ground terminals including the cylinder block ground. All the 4 SWG cables on the machine basically. A comment regarding valve clearances. Generally they close up over time. The longer an engine is run without checking/adjusting the clearances the more likely they are to be tight. Valve Lash Setting (cold engine) Inlet valves ... 0.25 mm (0.0098 inch) Exhaust valves ... 0.25 mm (0.0098 inch)
I'll need lift the cab and hook up some leads to the battery and run them from under the cab where the battery is located to check cranking voltage, but I will get that done this afternoon when in the shop and post the results. I unfortunately am working alone with no assitance.
Follow up results of continued diagnostics Voltage drop is from 12.8 to 11.5=11.2 during cranking. Removed all fuel lines and blew through them. Again, verified electric fuel lift pump is working. Discharges at high rate into a container. Applied 12 volts from a seperate battery directly to the fuel shut off solenoid and crank engine over - no start. Removed injector return end cap, and verified fuel does come through return line when I jumper the electric lift pump to run. Removed solenoid again and verified operatio. Although, I do not understand how it would work. I am used to seeing a plnger or pin either in the solenoid or space where it screws in to that would move and block fuel flow. This fuel solenoid has an opening on the end, and an internal plunger that moves. Looks like there are tiny holes in the solenoid body that allow the fuel to bypass when the interanl plunger is closed. ??? Engine valves checked. Within specs. This injection pump has another solenoid mounted which is suppposedly a "cold start advance". Does anyone know how this solenoid functions, purpose? I did jumper 12 v to it to see if it clicked, and it does. Starnge though is that I jumped it through the harness without disconnecting it and apparently the same circuit provides the 12v to the lift pump because the lift pump came on also. BTW, the lift pump turns on with key on, runs for about 5 seconds and then shuts down if you do not crank it. This is not a new symptom. It has operated like this always, including before the no start issue began. Any ideas?
Check the compression on the engine thru the glow plug holes and post the results. Note- remove all the glow plugs on all 4 cylinders, test one cylinder at a time, with the other three open. Do all the glow plugs work and cycle properly. Does the engine have a even cranking sound or does the cranking sound have an uneven pattern? Rings, injection pump pressure, slight bent rod from to much ether.
As above i would suspect injectors. Im always suspicious of injectors as i had numerous failures when we went through the transition of Teir 1 to tier 4 emissions and all the teething problems accompanied with the change. Mostly associated with poor fuel quality and poor hygiene when changing filters, pre filling filters ect. Watching people pre fill fuel filters just about makes me cry. I would measure the leak off from the injectors. Its easy. Find some clear tube thats the same size as the leak off hose. Run the hose into four cups. Crank the engine and measure how much fuel comes out of the lines. There will be a spec for volume. Or pull them and have them tested at the local diesel service.
The glows plugs on this model only energize when the engine and air temp are at a very low level. They do not energize at summer time temps. I've only seen the indicator lamp for the glow plugs a few times, and it was cold outside. Engine cranks on a steady pattern. No low compression cylinders. Again, the engine will start and run normally with just a very small shot of ether. No power loss, overheating, etc. As I mentioned in my first post, this progressed from an intermediate issue where it would occasionally do this, but smoke would puff from the exhaust indicating at least a bit of fuel getting through. Progressively worse until now when it will not start without a very brief shot of ether, but runs normal. This is a fuel issue I would think, but I am stumped. Friend that is diesel heavy equipment mechanic is also stumped.
If you say that the engine valve clearance is within specification, then the fuel injectors remain under suspicion. Small particles of dirt clog the nozzle holes, the fuel stops spraying properly and just pours. And to start the engine, you need a fuel mist, not a stream. So check the fuel injectors for spray. If desired, this can be checked directly on the maschine. Remove one injector at a time, connect the injector to the outside, start the engine on three cylinders and watch how the fuel is sprayed.
When the cold start advance solenoid is activated the injection pump supplies additional fuel to aid in starting. This usually has a dependency based on engine coolant temperature. Attached an explanation of the fuel system operation.
How about messing with the inj pump timing.? It’s easy enough to do.. 3 nuts and turn the pump a smidge. Be sure to mark the starting point..
Nige has been a BIG help. With his provided schematics, I learned that the Cat parts breakdown lists the solenoids incorrectly. The one they show as fuel shut off is actually the cold start. Some parts breakdowns list them both as fuel shut off. Even their printed materials in the dealer parts shop is incorrect. Continued diagnostics tomorrow afternoon, and I'll update evveryone on findings.
U can get the correct parts by getting the injection pump part number and calling a diesel injection shop.. But don’t use the Cat p#.. If it’s a Bosch VE pump..?? Get the 10 digit Bosch #.. Example > 0 460 424 303.. Good luck
All, I have received a Tech Bulletin from Cat they may be of some help to others in the future. Not sure this is the issue, but thier help is appreciated. See attached.
Check your messages. It also may be worth pointing out that there are two types of fuel injection pump used in this particular line of engines depending on the Engine Arrangement Number. One type has both the fuel stop and cold start advance solenoids mounted vertically as per the illustration below. This is the illustration used in the Service Magazine that you attached above, with the caveat that both illustrations are titled "typical example" The second type of FIP has the stop solenoid mounted vertically (as before) but the cold start advance solenoid is mounted horizontally. See below.
The problem described in this Service Magazine, in my opinion, does not correspond to the symptoms on your engine. The Service Magazine states that the engine does not start at all, but yours starts with ether and works fine. If your solenoid was stuck in the closed position, cutting off the fuel, then ether would not help you.
Deimos - That is why I am stumped. No fuel during starting (no smoke from exhaust) but runs with normal power when a VERY brief shot of ether is used to start it. Still continuing diagnostics. Ill post any up dates. I had a CAT Technical communicator send me the following - "If you have a way to check the injection leak off? We have seen some in the past have a leakage issue causing a hard restart" Not sure what he is refering to? Bleed off amount from the return lines from the injectors?
Yessir.
I agree that there may be a fuel leak into the return line through the injector. The design of the valve needle when worn will bypass fuel into the return line. To check for a leak into the return line, the injector must be installed in a tester, create a fuel pressure of 1030 kPa, if the fuel pressure drops in less than 5 seconds, then you need replace the injector. (1) Fuel inlet (2) Fuel return (3) Body (4) Pressure spring (5) Retaining nut
copied and pasted from the last one of these...... You're likely going to end up putting an injection pump on this machine. Those zexel/VE style pumps get internal wear in the rotor and head, and when you ether it, you get enough speed/fuel flow to overcome all the internal leak points. One thing to check is make sure you have good cranking speed, but frankly, if low cranking speed is causing a no start, the pump is on its last leg anyway.
Latest diagnostic update - Ok, so, concerning cranking speed- I removed all battery cable connections and cleaned connection points, installed a new battery. This think sings when spinning over. Faster than ever. Still no smoke or run. Takes an even smaller shot of ether now to crank/run. Runs normally with no loss of power. Beginning to believe the Injection pump ideas submitted here. One last thing I am goiing to do, is remove an injector, and rehook it to the injection line, crank over, and see if I am getting a fuel spray. I do get a high pressure squirt from the line when loosened at the injector and spin it over. Any thoughts anyone? Can diesel shops rebuild this pump versus buying new? Does anyone know the timing process for re-installing a new or rebuilt pump, that they would like to share?
The forum’s resident expert @thepumpguysc could answer that question and only lives in the state next door if it can be refurbished. If it comes to the point of removing the FIP the timing, etc, procedure will be available.
Hanging an injector outside the engine is an excellent idea.. just because it’s pumping fuel UP TO the injector, doesn’t mean it’s got the volume/pressure to open the injector.. If that shows good.. try rotating the pump, which will change the pump timing.. Just make sure you mark the starting position.!? Ya never know, it might be something as simple as a timing adjustment..??
I am an old man, from the old school. Are you sure you have enough cranking voltage to wake the PCM up?
My outfit had a bunch of 140M1 mosheeens that would crank all day, no fire. The voltage required to make the computer go to work was a bit higher than we were used to with simple solenoids.
Unit has hot battery and good connections. Voltage drop is only down to 11.9v. Minimum required according to CAT Tech is 9.0 v.
Checking the injectors for leaks and spray quality will be the least expensive procedure. Fuel pumps very rarely and are unlikely to fail at such low engine hours.
In my experience fuel pumps tend to fail much more on these smaller engines because of the lack of care taken when refuelling that introduces water and contaminants into the fuel tank, then the fact that maintenance practices can be suspect. The pumps don’t like that.