Ok, back again. Got the hydraulics problem solved and now the motor keeps dying. It will start up and run maybe 2 minutes sometimes and 15 minutes at the most and then it will scale back like it is going to idle and then just quit. When it is running it runs good, but does not last long. Here is what i have done so far: 1) Changed primary and cleaned lines, blew out lines to tank. 2) Changed secondary and blew lines to tank. 3) Operated it on mechanical pump, no change 4) operated it on an electric pump, no change 5) Blew lines out to tank, no change 6) Cleaned filter in the injection pump, no change 7) Looked for and can not find the return line check valve, (do they even have one?) 8) Installed a rubber hose directly into tank thru the filler port to bypass hard line, no change. 9) Put rubber line in 5 gallon can directly and no change. 10) Exhausted all my patience, got mad and kicked tires, no change. So, if anybody out there has any ideas please let me know so i can try whatever it is i am missing.
Not familiar with CAT products, could you post a pic of your injection pump. A pic of the serial tag would help the CAT knowledgeable to help you better. Is this a pump-line-nozzle engine or common rail?
Are you positive its a fuel problem? I have had electrical shutoff solenoids act similar.
Is there a screen on top of the mechanical pump? Did you clean that?
Here are the pics of the pump and rail. Pump was rebuilt 6 months ago. I can not get the plate because it is mounted on the underside of pump but here is the number of it :" Rebuilt Injection Pump 4.236 Perkins and Caterpillar 3343F742".
Yes, screen is clean. I can get a flow of fuel to the pump by taking the INPUT line loose. Has a good flow BUT there are bubbles in the flow. I let it run a long time and bubbles did NOT clear up. Now i have to find the air leak on the input line somewhere. Must be a hole in the line somewhere? OR is it normal for electric pumps to produce bubbles? Seems unlikely to me.
No, am not sure of it. Never thought of the solenoid being the source. Is it possible for the solenoid to act that way? How can i eliminate the electric one and go to a manual one?
you don't say anything about fuel flowing from inj. pump to fuel storage tank,, must have flow back to tank to work right, reliefs pressure and get rid of air
The bubbles are a concern. Seeing what you're dealing with, the first issue I see is the fuel lines. Those damn rubber olives. They suck air, leak fuel. Wherever you can replace a length with hose barbs and rubber line, that's what i would do. That water separator/filter housing is another nightmare. The top and bottom seal/gaskets get dry and suck air as well as the central screws seal ring on top. Since it's a Perkins , do you have a fuel line that runs across to the intake manifold? Most are equipped with a flame start which will sometimes cause aeration problems as well.
Oh yes, you are correct. I did check to see if fuel was going back to the tank and it has a free flow back. I can hear it flowing back into the tank, engine off and key on with the electric fuel pump on. Stoll don't know why the fuel has bubbles in it.
No flame start on this one. Fuel lines are direct to the filters and fuel pump. I bypassed the separator and ran line direct from tank source to the electric pump. Was checking just what you are talking about and it did not solve the problem. I took the mechanical pump out of the equation and that did not help. I just replaced all rubber lines with new rubber hoses and that did not help. I am now suspecting the injector pump itself. No matter what i have done so far, the max running time is about 15 minutes before it starts shutting down. Slow shutdown, not immediate like turning key off.
This is a job for thepumpguysc.
Was the pump "rebuilt" for this concern? Or did this appear after? From your description it sounds like it is running out of fuel. When it starts to die try a squirt of ether and see if it makes a difference. I mean a squirt not 1/2 the can.
Does your muffler rattle a lot? I'm wondering if a broken baffle could be choking the exhaust.
Actually it dies too quickly for that action. However i do try to start it back up with the ether and it does try to start but wont stay running. Let it sit for a few minutes and then start it with ether and it will run for max of approx 15 minutes.
No, the muffler is ok. But you do stir up some doubts about the intake system. Will check the intake filter today to see if MAYBE it is clogged up. That would be embarrassing.
Well, i changed the intake filter that was not very dirty anyway, but changed it anyway. NO CHANGE, ran about 10 minutes, scaled back to idle then died. So began another approach. This time i took a closer look at the pump. I discovered there is a chckvalve in the return line that comes off the pump. The attached photo shows where it is located. First off i loosened and removed the line that attaches to the checkvalve and turned key on. There was very little fuel coming out of the hole. I then pulled the checkvalve and turned the key on and the fuel ran freely. It did NOT squirt out, just kind of FLOWED out,,, is that the way it is supposed to be?? In contrast i took the supply line loose on the back of the pump and fuel Squirted out hard. I then looked at checkvalve which seems to have a steel ball held in by a spring. Pic attahced. The ball is tight in the tube and does not rattle when i shake it. Is that the way it is supposed to be?? It is hard to depress with my finger. Not sur why. Also not sure how that spring and ball are held in the tube.
OK, another question while i am on this subject of fuel return. I can not figure out the sequence or logic on the fuel return line. For instance i know that when i turn the key on i can hear fuel coming back into the tank from, i assume, the return line. So in my prior post i took out the line to the "check valve" and discovered there was no flow from the line or the pump. However when i took out the check valve itself the fuel flowed out when i turn on the key. So question is, at what point does the fuel decide to enter the return line and from where? Is it returning from the secondary, pic attached, or does the fuel go thru the pump and exit thru the checkvalve? Note that there is a "T" on top of the secondary filter. So what keeps the fuel from flowing back into the pump check valve.
The pump check valve. The spring loaded ball does 2 jobs, it maintains pressure in the pump, once the pressure need is satisfied, the ball unseats and allows fuel to get by to return. The pressure is always pump first, so flow will carry away . Does this make sense?
Yes. I do understand that logic. After i took out the check valve i set up to clean it and as i was looking at it i can see a tiny pinhole right next to the ball in the body of the seat. I tried to take a pic of it but it would not come out right. Is that the way it supposed to be? It appears to me that the pinhole would allow the fuel to go straight thru the valve thereby reducing the pressure needed for the pump? So, if that check valve is defective would that be the cause for the way the engine is acting? ie run for a few minutes and then just taper off to an idle and then just die? Wish i knew more about these things.
If, IF it's starving for fuel, you should have a dry fuel filter, but you have an electric fuel pump. Theoretically, it shouldn't happen. Do you have a separator prior to the electric pump? It could be full of garbage restricting fuel flow.
Yes to separator. Filter has been changed trying to fix this problem. I even bypassed the separator to see if it would fix it and nothing changed. I am almost convinced it is the check valve because it has that pinhole in it. I just ordered a new one and should be here in a couple of days. Hopefully that will resolve the issue. One thing is certain, it IS fuel related.
Oh yes, i forgot to mention this. After the engine died the last time i checked all points i could looking for fuel. I broke open the supply line to pump from secondary and there was fuel there , i took out the small filter in the rear of the pump and there was fuel, i opened the bleeder on side of pump and there was fuel and last of all i removed the check valve and there was fuel there. So in fact, the fuel is getting to the pump. Question is, is there enough pressure ? Also/or does that pump have an internal pressure switch in it? May be shutting down from too much or lack of pressure??
I'm pretty confident that pump has the mechanical pressure regulator and only the electrical shutoff solenoid. I don't think there's a whole heck of a lot going on in there. You have the dreaded Lucas CAV injection pump. They're fine for what they are but, there are whole websites dedicated to troubleshoot and correct issues with this system. I can't see your entire system and injection pumps are not my specialty. I would take a few minutes and google lucas cav fuel system troubleshooting. See what you find, it could be as simple as a stuck inlet valve or gummed up something. Good luck, and please share what you find.
OK, Will do. Thanks for the tip.
Unless I missed it, I haven't seen anything in this thread about the fuel shutoff solenoid being removed and inspected. Bench tested it? It has been a while (years actually), but I have replaced many a CAV shutoff solenoid for no start conditions. Resistance of those solenoids is 16 ohms.
Jumping in on this thread kinda late but The Lucas is a rotory head pump like the Roosa . Many years ago I had a 580 E that had the same symptoms, the check valve at the base of the pump was my problem. The Roosa pumps do the same thing when the governor ring deteriorates and plugs the check valve in the top cover, It would be interesting to see what happens if that check valved could be eliminated for testing purposes.
OK. I have not done that because the engine does not just suddenly stop, it starts by running slower and slower then just goes to idle and then dies. I will pull it today and check it out.
Good idea, how do i do that? I was wondering about that yesterday and did a search and came across a situation where this fellow advised somebody to take a punch and break the glass ball in a check valve and then it would run? Not sure how that works BC I understand that the CAV has to have a certain amount of inside pressure in order for it to work. If it has no CV then it would be a direct flow thru?
Direct thru yes, Roosas for years had no CV in them and ran just fine. Do not know about Lucas. When it shuts off does it take a while before it will restart, if so you could run it till it shuts off, remove the fitting and see if it restarts immediately. I would see if it will run without the check valve, Incidently, you described perfectly the same style CV used in a Roosa, glass ball and a little notch you can see through by the ball.
Good information and i will try what you suggested. Yes, when it shuts down it will not start for 20 to 30 minutes. I always have to give it a shot of ether to get it going every time, even when it was running "good". Yes, this CV has a tiny pinhole right next to the steel bearing and today i went to the shop where it was rebuilt and talked with the fellow who actually does the work. He inspected the CV and declared it perfect and working. Told me that high internal pressure would shut the motor down similar to what i described. My question, which he could not answer, was, if the CV is working how could it build up internal pressure? He also told me how to bypass the electrical solenoid. Just take it out and remove the plastic plunger and reinstall it. Said i would have to shut it down manually. Gonna try it again later today.
Well, i have exhausted all my theories and tried just about everything that has been suggested and have concluded that it is indeed the injector pump,,, AGAIN. I just installed a brand new electric fuel pump and had the exact same results as before, it will start up and run for about 10 to 15 minutes then start losing RPM's and finally just idle and die. There is nothing else i can do to explain it and there is nothing left to change out. All hoses, filters have been changed at least 2 times and fittings have been checked for tightness and all clamps have been re-tightened. I have decided that a new pump is the only solution. The people who rebuilt it six months ago?? Well they said it had no warranty on it and maybe they would have to rebuild it again. NOT on their life would i take it back there. My take on it is , if a company can't guarantee it for more than six months,,, then they are a failure from the beginning.
Agreed, but, you have to look at the rebuilders side. They provide service, then some yahoo put water contaminated fuel in, or uses a jug that had DEF in it. You see where I'm going here? Have you checked the solenoid as suggested? Did you check it again immediately after shutdown? Was the Google search on your fuel system any help at all?
Checked the solenoid and found nothing. I disabled it by taking the plunger out of it (per the rebuilders instructions) and that had no effect except it would not turn off by the key. The search covered pretty much all the territory i have covered and all the action i have taken. Nothing there that was new or could help explain. I know when i am whipped and that is why i am going to a new injector pump. Thanks for all your help. We did the best we could and time to just bite the bullet and face reality. LOL
Use the @thepumpguysc . I have not personally used him but I have not seen one complaint and he is very helpful to members here. I am sure if you reach out he can set you straight.
Restricted fuel return circuit such as a pinched hose, partially plugged hose, internally collapsing hose. Also, was the fuel tank vent checked?
First off i like your motto: "Quality repairs are the rule, not the exception!" Too bad that most people do not practice that. Unfortunately most business just want the money at all risks. Now, The vent line was removed and found it was clear, reinstalled. Removed return line at the secondary and blew air thru it, it was free. There are no rubber lines on the return line. I turn on key , engine cold, and the electric pump is pumping fuel back into tank and can hear it flowing back. This procedure was done BEFORE i started the engine after sitting for a while. It sounds like the return line terminates at the top of the tank fitting because it makes a lot of noise in the tank. So here is the summary of return line tests. 1) with engine cold the return line is free and fuel pours back into the tank. 2) after the engine dies i leave the key on and listen for fuel return back to the tanks and there is none. One thing i did to test the fuel flow was after the engine died and i left the key on so pump would keep going, i cracked open the supply line INTO the pump (at the rear) and there was plenty of fuel flowing out. However when i cracked open the line OUT at the CV I had no fuel coming out. I then tightened the lines back and listened for fuel return to the tank and there was none. Any ideas? i would hate to install a new pump and get the same results because i missed a minor item. LOL
Just a WAG. Did you check for a plugged or partially restricted leak-off line from the injectors? If it is plugged, the injectors will hydraulic lock and the engine will die fairly quickly. If only partially restricted, it may take longer to die. The leak-off line is the small one that joins all the injectors together and then is usually teed into the fuel return line from the injection pump. The line could be partly plugged or squashed or that branch of the Tee could be restricted. Disconnect it from the tee(if it has one) and run it. You will have to run the return lines into a pail to catch the fuel so it doesn't make a mess.There should be a small amount of fuel coming from the leak-off line which is normal.
Well, i did not look at that aspect because it never occurred to me. I will take a look at that today. My intent to day is to remove the pump and take a close look at it. I found another "re-builder" that may be more reliable who agrees to "take a look" at it . Not sure what all that means. The process of rebuilding is a mystery to me as all i see in a "rebuild" kit are a bunch of O rings and gaskets?? Why does it cost so much? Kit is cheap. Anyway, after much searching and research i personally believe it is internal pressure related and possibly tied to the governor. This thing is driving me crazy.
Instead of clutching at straws - send a PM to @thepumpguysc
2 things>> 1– do u know there is a plastic filter screen IN THE PUMP.? It’s under the large inlet nut, 15/16” Let me know if you knew that and have checked/cleaned it.. 2– the filter ur running.. on that type of filter and head, U HAVE TO put the oring UP IN THE FILTER HEAD... NOT “ON” THE FILTER.!! It looks like it goes ON the filter but it doesn’t.. it WILL choke off the fuel.. It’ll start and run until it depletes the fuel and then shut down.. and then u have to wait until it fills .. Take the filter back down and SEE where the oring is.. Let us know about the filter in the pump inlet.. it requires instructions to remove... or bad things will happen..
Yes to the plastic filter in the pump. Pulled it and was clean as a whistle. That secondary filter is a PITA and yes that o ring at the top goes in first. I get a good flow of fuel from the input line at the rear of the pump, so fuel is there for the pump. Pump is failing somehow. Its at the shop now and i will know results on Monday. Will share what the problem was.
Why am I thinking this was something simple but kept getting overlooked
I got the pump back from the shop today. My reason for posting today is to bring you all up to date on the possible problem with my Cat 426 backhoes issue. Hopefully no one ever has this exact problem, but in case they do, you can see what the potential problem is. It turns out the pump works just fine on a test machine. He showed me a video of the test which included the pump mounted on the machine and the resultant pressure it generated along with a visual on the clear hoses attached to it. The rebuilder and i had a long conversation where i explained to him that the machine ran fine until it got hot and then it just quit running. His answer? It could be the pump head is bad! That was his only explanation. He could not duplicate what happened when the pump was on my tractor because the bench test would not heat up the pump to the degree that the tractor would. There are two ways to test his theory: 1) replace it with another pump 2) replace the head on the existing pump. He says that it would be cheaper to just get another pump. So there we have it.
please let us know if it works
If it runs good on the calibration stand, it should run the same on your machine. Something is being overlooked.......Ide bet my next check on it.
I was able to get the pump back on today but bad news, it is worse now than it was before. It looks like they took it apart and put it back together wrong as fuel is pouring out of the head and around the seals. No start of course and no fuel to 2 of the cylinders. The first and last cylinders are getting fuel. Yes, i did bleed the air from ALL of them. Got a feeling that i am in a town where professional service does not exist. So why don't i take it back you say? Well, first off there was no charge just to check it out and second, if i get the same treatment as before, who knows what i will end up with. So, i am going to cut my losses and just get things done elsewhere. Tomorrow i will order a new one from somewhere in the East. Not impressed with what is available here. It looks like i will actually never know what the original problem was.
FWIW ! There is a master pump rebuilder helping you already. Send it to him. He did mine and when I got it back it looked like a new pump. It worked like a new one too. [email protected]
Lol.. thanks guys.. but we all know the saying:: u can lead a horse to water... Lol
Is this a professional rebuild shop? Or just someone thats says they can rebuild one? There is a HUGE difference there.
sorry about your feelings about this site lol why comeback for information?? we like it and its free help, hope you don't anymore repies
I hope, I think he is referring to services available to him in his area. At least i hope that was the meaning.
Your correct. He's not dissing this site but his own area
They are a "Rebuilder" of injector pumps, and the only one in town i can find. The guy who "checked it out" and made video, well serious doubt about that too. Yes, its all about where i am, not about this site at all. I have had great success with all my questions and participation is excellent. It seems that there are many more shops and retailers of equipment in the East than here. When i was looking for a backhoe to buy the most machines i found were there, much too far to ship to West Texas.
Not talking about this site.
Thepumpguy can handle most pumps, that is not a complicated pump as pumps go. you could also get a used one, don't know what thepumpguy would say about that? You have a fixer upper, that probably sat for a while, this is just another kink to work out, I wouldn't get mad at the pump shop that rebuilt yours until you get this resolved and know what the issue was. Since you have had several issues with this machine, does the engine make any smoke as it's slowing down? Can you tee into the line before the injection pump and hook up a pressure/vacuum gauge to see if the pressure drops/vacuum builds as it slows down and shuts off? Good fuel pressure, and a clear return to the tank eliminates anything outside of the pump, that should have been done before the first rebuild.
Yes i have done just about everything that has been mentioned except what you have suggested about the pressure test. The return line thing you mentioned triggered something i did not understand about all the tests i did. When testing to make sure i had a good return i could hear the fuel dumping back into the tank. Key on motor dead. (electric pump) So, I went back over my notes on all i have done just to see of maybe i did miss something and the one thing i saw that just stood out that seemed odd was the return line test. I took the lines loose from the "T" at the top of secondary and removed the T. I turned on key and fuel shot out of the top of the filter housing where the T was. I thought that was normal. But,, Now that i think about it it might be more ODD than normal? Reasoning that the return line originates at the front of the pump where the check valve is AND from the injectors too, i would guess that the fuel returning from the pump and the injectors would enter the return line unencumbered and then return to the tank. But if there is high pressure fuel coming out of the filter top into the T , it would seem that the fuel entering the T would overcome the fuel from the pump and injectors and block it from going back to the tank?? Any thoughts on this would be appreciated.
This sounds suspicious from what you have said. From my experience, the return from the injection pump and injectors should return directly to the tank via its own line and not be connected to any filter head or any part of the suction line unless maybe that T has an integral check valve or pressure relief(or pressure maintaining) valve in the branch coming from the injection pump return which would allow return fuel back into the suction side. I've never seen it, but then i've never worked on any of the cat backhoes. Some manufacturers do strange stuff. I don't know what the purpose of that little short line is from that T to the banjo fitting on top of the filter head. Maybe its a constant-bleed feature or similar. Somebody should be able to tell you that has worked on these perkins engines. Its been a long time since i worked on a perkins with a cav pump so my memory is fuzzy.
The images below are what the fuel lines, filter, injection lines, etc. should look like.
Attached is a pic of that filter and line. First there is that little T (with the line removed that goes to front of pump) , you can see and when i turn on key fuel squirts of it. I took the banjo bolt out and turned key on and fuel squirts out as well, so i know that the fuel is coming from the filter direction and not thru the pump. I also logically think this is not right. There is no check valve in the small T or in the banjo bolt. I would really like to understand whether this is the way it is supposed to be or if it is a malfunction of some kind.
Nige, that pretty much looks like mine. I was wondering about item #8 in the image as to whether that is a check valve or not? Kind of looks like a bolt? but also resembles a CV?
Sorry, missed an illustration.
Great, looks exactly like mine. The problem is there is pressurized fuel at the banjo bolt #19 into line # 9 which in turn forces fuel into line #20 that connects to the injector bleed off lines. Not sure that is what should be happening. It also pressurizes line #25 which goes to the front of the pump which has a check valve in it. While the pressured fuel from the pump won't overcome the CV , maybe is is stopping the natural flow of excess fuel FROM the pump back to the tank?
Quick question. Go back to the illustration in post #60. Is there any chance that O-Ring #9 is missing or you have two of them on there.? It's not unusual to find either of those scenarios. If you mean #8 on the last illustration of the fuel injection lines it is listed as a "bolt", when obviously it is a pipe connector. However it is NOT listed as being a check valve.
I did look at post #60 and i just replaced that filter recently and have in the past. The first time i replaced it i found that the O ring goes on #9 fits over a protruded hollow shaft the mounting bolt goes thru. Well that shaft has a chuck out of the side of it. Looks like someone in the past either beat on it or it just broke off naturally. Not sure if that cause a problem BC the O ring seems to fit and sits firmly on the shaft past the broken part. Yes,m only one O ring there now. Could that be a problem? Also, thanks for clarifying the item #8. My manual is not detailed enough to see that in detail.