Hi, My 1991 JCB Sitemaster backhoe is having a fuel delivery problem. I can't tell if it is the fuel solenoid, the lift pump or the injector pump. If left alone for a day or two it will run for 10-15 minutes and then start to bog down and then stop. Sometimes manually operating the lift pump will get it started again, but it will have very little power and then die. While manually operating the lift pump I can see returning to the tank via the "clear" return line, but I also see bubbles that don't stop with extended priming. It seems like I might be sucking air in somewhere, but that would have to be before the lift pump wouldn't it? The filter is new. The solenoid and lift pumps are only a few years old. Any help, as always, is much appreciated. Thanks, Chris
Check the feed from the bottom of the tank for blockages , there is a water trap on the inside of the chassis injector pump side , also a gauze in the top of the lift pump too
Also on some have little black thick rings on the fuel suction pipes to help sealing also as d4c24a said water trap make sure if its a plastic one with a domed nut on the top the o ring is present under the nut and seal foe the bowl is good and general secure all pipes also worth a shot had it before a piece of plastic floating in the tank gets sucked onto pick up pipe and then when engine stops it floats off again also make sure the fuel cap is able to breath.
I can't find any leaks. I placed a clear section of tubing just in front of the lift pump to see if bubbles are being drawn in, but no bubbles. On a warmer day (~55F) the lift pump seemed to be pushing fuel (with bubbles ) back into the fuel tank. Today (~45F) it doesn't seem to be doing that. When it starts I can see bubbles in the return line, but none in the clear line before the lift pump. Is there a place on the injector pump that would be drawing in air? It would have to be on the intake side of the IP and be below ambient pressure. Does the IJ have the ability to have a low inlet pressure? Where in the IJ could a leak possibly occur if a seal was failing? There is a small bubble in the fuel filter bowl, but it seems fixed in size Thanks, Chris
While the engine is starving for fuel try removing the fuel tank filler cap. Do you hear any noise that sounds like there is a vacuum in the tank and does the engine operation change at all..? that would rule out the cap. Did you check the water trap mounted on the inside of the chassis between the tank and the injector pump as d4c24a suggested..?
Just went through this on my New Holland. Probably not many similarities but I had rusty crud in the tank that clogged at the first small opening being a banjo fitting on the sediment bowl. I would get a tube with a piece of clear tubing to siphon some off the bottom of the tank to see if it has any water or rust in it. I hear algae is a common problem too.
Some of the Delphi Inj. pump models have a "boost diaphragm" on the top or side of the injection pump top cover.. They are prone to rupture.. the tell tale sign is the fuel tank will pressurize.. and bubble.. If you can provide the inj. pump #'s.. I'll look it up and see if it has one..
I dont think the 1991 proj 8 had the diaphragm on the pump ,on the fuel filter housing i guess its either a long spin on or a long filter with a center bolt.on the spin on check that the rubber seal is in the top of the filter which seals the center threaded section as this missing has caused me problems before , on the long filter with the center fitting bolt 7/16 headed check that the housing has not gone pours and that the little o ring is ok under the head of the bolt and also the bowl on the bottom is good.to bleed pump up with lift pump until you see air on the clear pipe from the filter head and then keep pumping until no more air in the clear tube. Have you had a good look in the steel pipe fittings for the black rubber washers that seal the pipes as this will also cause you problems as thing expand and contract.
I thought I had made some progress, but I'm dead in the water again. 1. Dismantled lift pump and found it packed with sludge. That helped, but still not running long. 2. Bypassed the fuel tank by running a line to the lift pump from a jerry can. It fired up and ran fine for a few hours. I decided to run it with the jerry can just to get something done before a big storm hits us and fix the connection to the tank or in the tank later. The problem came when I ran out of fuel. I refilled the jerry can and then it wouldn't start. The lift pump is priming the system. On this version the injector pump is self priming or almost, anyway no bubbles in the return line when manually operating the lift pump. I loosened a couple of the injectors and I can see fuel pulsing as I crank it over. I even see some smoke coming out of the exhaust pipe, but it refuses to start. I'm confident that there is fuel getting to the injector pump and at least nominally to the injectors. My only thought is that the injector pump is failing. I checked the fuel solenoid and I can feel it click when I turn the ignition on so it seems to work. Is there a way to check the injector pump? Thanks, Chris
JCB Jeff, well I haven't looked at the seals on the fuel pipes, in fact I didn't even notice they existed! I'm not seeing any leaks on the pressurized lines though. Where are these seals? Are they in the nut cap or are they in the fitting the tube slides into? I just noticed your msg so I haven't gone to investigate. Thanks, Chris
Hi Chris if you remove the steel fuel lines from say the filter head you will be able to see the fitting that slides on the pipe and then on the pipe a swage which allows the nut to pull up the pipe tight but then look inside where the pipe came from you should have a rubber ring about 1/4 " thick these often get worn or breakdown and sometimes if been dismantled can partially block fuel supply or even drag air in on the suction side . not sure if they are on the lift pump side though?. The little pipe on the filter head is a common culprit for this. But check the filter head ring inside of the fuel filter big round one on spin filter and o ring on bolt on tall filter as this will allow the return line open to inlet side of filter.
Sounds like you found your problem with the sludge, at least narrowed it down. Running for a few hours is success in my book. I don't know this engine, but my normal way to bleed the injector lines when run out of fuel, is to leave the lines at the injectors (or even just one of them) loose until there are no bubbles, or it starts to fire, then tighten it up. Put a battery charger on it, and give it plenty of time so you don't overheat the starter. A little shot of ether while starting (as long as you have no glow plugs or intake heater) will help it prime real fast, the engine will run on a little shot every second until it revs when the fuel comes on. Set the throttle in the middle or fast.
JCBJeff, Are these seals readily available or a special JCB part? If so, what is this tubing connection style called? Thanks, Chris
The seals are available from JCB but I guess you might find them from a Perkins engine dealer if you have one near you I can have a look later and give you some part numbers for jcb
these are the rubber olives
Making progress. Got it to start by charging the battery. Although it seemed like it was cranking fine, it cranked even finer. Could be coincidental, but it well with the external tank. Then I pumped the tank and got a bunch of red sludge. I kept filtering the fuel through a fine screen back into the tank so I could pump more out. Got quite a mess that would certainly be messing up the intake to the fuel line. Then I drained the tank and pulled the side cover off. The walls of the tank are covered with a weird red slightly rubbery stuff, the same as what was pumped out. View attachment 151891 The stuff in the bin is what I pumped out. The stuff in my hand is what I shaved off the walls of the tank with a putty knife. Anyone have an idea as to whether these tanks were coated? At this point I have to admit that I used bio diesel in this unit for years. It is really good at keeping the metal parts clean, but it destroys most polymers. If the tank was coated then this must be the remnants. Either that or it is an alien life form. Thanks, Chris
Making progress. Got it to start by charging the battery. Although it seemed like it was cranking fine, it cranked even finer. Could be coincidental, but it well with the external tank. Then I pumped the tank and got a bunch of red sludge. I kept filtering the fuel through a fine screen back into the tank so I could pump more out. Got quite a mess that would certainly be messing up the intake to the fuel line. Then I drained the tank and pulled the side cover off. The walls of the tank are covered with a weird red slightly rubbery stuff, the same as what was pumped out. The stuff in the bin is what I pumped out. The stuff in my hand is what I shaved off the walls of the tank with a putty knife. Anyone have an idea as to whether these tanks were coated? At this point I have to admit that I used bio diesel in this unit for years. It is really good at keeping the metal parts clean, but it destroys most polymers. If the tank was coated then this must be the remnants. Either that or it is an alien life form. Thanks, Chris
double post
Mmmmm, chicken fried diesel to borrow a phrase... That's what biodiesel does when it sits. Deere says biodiesel has to be used up in 45 DAYS! I've never seen a steel tank come from the factory with any coating, unless it was an old gasoline tank and that was terne I think.
He did say it was a 91.. Like Delmer says.. probably not new.. Glad you found your problem.. Has anyone mentioned the filter in the injection pump?? Once you get the tank cleaned.. and start and run it.. IF it has problems.. we'll visit THAT ONE..
After a while of limping along I have come to a halt. I had place an inline filter before the lift pump just to keep the sludge at bay. Recently it had been operating strangely in that the throttle was verrry slow to repond, like tens of seconds to get to full revs. Once it warmed up it got more responsive, but it would often die on idle when rapidly backing off the throttle. Today it has ceased to function. I have checked the screen on the lift pump; a little sludge,but not blocked. I loosened the injector lines and I can see fuel pulsing out. Perhaps not as strongly as before, but not certain. I'm thinking it 's time to remove the injector pump and look at the filter on the inlet. At least it looks like the pump has to come off. Any suggestions on removing the pump? Is it rebuildable in a home shop? Is it worth rebuilding at home? Thanks, Chris
Here are the numbers on the pump Lucas CAV Type 902 DPA 3348F2 Ser 07023 DGG (66?) Mod 2543C610GM/2/2420 (might be 2643C) Thanks, Chris
You don't have to remove the pump to clean out the hidden filter.. Shut off the fuel.. Remove the line going into the back of the pump. Remove the large 15/16" inlet nut, Under the nut is a spring, remove it w/ needle nose pliers. The filter is around the sides of the pressure regulator & housing. Using a small screw driver, hold down the guts inside.. [pressure regulator] Using a small 90* pick or scribe, feel for the plastic filter around the sides of the housing.. And PULL UP.. WHILE HOLDING DOWN ON THE INNERDS. The filter is a plastic cone.. just blow it off and reinstall.. What you don't want to happen is>> allow the pressure reg. to lift up or come out.. Good luck and I hope you get this before removing the pump unnecessarily.. TPG
BTW> you left off the last 2 digits on the pump #. 3348F2??
Ok I think the numbers is DPA 3348F210 although the zero is partially obscured in the photo and I"ll have to go take another photo to be sure. I haven't removed the pump yet although I started to. It seemed very crowded to try and get into that area. I'll give it a try in an hour or so. Chris
So I'm wondering why I can see fuel pulsing out of the injector line when I loosen them and crank the engine, but get no ignition. What would cause that ? Also, what about the very slow throttle response? The actuator on the injector pump is moving when the throttle pedal is depressed, but it takes forever to raise the RPM? Is that an indication of something inside the IP? Thanks, Chris
The filter may be clogged, not allowing enough fuel to pass thru.. You might be asking it to run with no fuel getting to the pumping plungers.. The more you push the throttle the more fuel it requires and if it cant get thru that stupid filter, your stuck.. Only thing there is to do, is look..
If you feel the need to pull the pump your going to have to access the front of it.. AND your going to need a puller.. the pump drive shaft has a nut and washer on a tapered shaft thru a drive gear.. OR have enough room to swing a hammer and a brass drift..
This is what I'm worried about. Looks to me that on this engine setup getting to the other side of the pump drive shaft is a major disassembly. There is not much room there at all. I'll start with the filter. I'm trying not to feel the need to pull the pump.
I think all you need to do is pull the radiator hose and maybe/probably the fan guard.. then a couple bolts holding on the little cover.. The hardest part is coming up w/ a puller.. it has to be small enough to fit in the hole or screws long enough to fit in the gear.. You cant use a jawed puller on it.. it has to be an eared puller.. like a steering wheel puller.. YUP.. start w/ the filter.
I would suggest you check all the lines and fittings from the tank to the injection pump in addition to the filter. When I went through a similar problem on my NH I ended up cleaning the tank, replacing the filter, replaced some of the rubber seals on the hard lines, and finally found a tiny bit of crud blocking a banjo fitting. I am sure all the stuff I did needed doing but at the end of the day my engine would NOT continue running until I found that blocked fitting and cleaned it out. I also added a small engine filter in front of my sediment bowl to head off any new debris and I have had to change that twice. That $3 filter is a quick cheap way to nip fuel problems in the bud.
You tell'um NH575E.. You have to take it ALL APART..