Old Isuzu 2.8 injector pump problem

Deutzdx3

Member
Does any one know about these pumps? Have a 2.8 in my old defender. Has been running ok, fuel bleeds back to tank daily, now I can’t get any revs. Barely keep it ticking over now. Changed all fuel, new diesel filter. Not changed lift pump but thinking about it. Any ideas? Pump rebuild? Typical as I’m going to change the engine out after Christmas but need it until then. [emoji106]
 

manhill

Member
Plastic container of diesel hooked up to the injector pump intake and raised as high as possible above it will locate which side of the fuel system is at fault if at all. Quicker than buggering about for days on end bleeding and reconnecting and disassembling.
Keep it on the shelf for any future fault finding
 

Deutzdx3

Member
Have been trying to find the issue with a gallon can perched on the wing. Still won’t run. Could the seals be buggered or injectors now blocked possibly.
 

agrimax

Member
Location
Co Down
Have you had a good look for a gauze filter perhaps in the inlet end of the pump or inside a banjo union that screws into the inlet? There may not be one and various sites on Google don't seem to know but some pumps have them,Terrano for example. My Terrano engined Navara has one and it took a few goes with a piece of mig wire with a hook on the end to determine there was one.....which was blocked.Maybe nothing to do with your problem but worth a check.
Another thing mentioned on an Aussie Isuzu Rodeo forum was that the seal on the shaft of the inj pump becomes hard and lets in air...........
If it won't run at all with a gravity feed direct to the inj pump,it's gotta be a pump issue.Any fuel from the injector pipes when cranking? What about the fuel cut off solenoid? Is it clicking?
 

Cowcalf

Member
have you got a good flow of fuel when you bleed it at the pump, if so its muck in pump or faulty pump but doubt its that.> have a few 3 litre Isuzu and I always install an electric fuel pump (£20 off ebay ) as it makes life so easy.
 

Deutzdx3

Member
So, just got it running on the gallon can. It ticks over no problem, a little rough running but runs. As soon as I go to rev it nothing. It climbs slightly and then just hunts and smokes and eventually cuts out. Start it again no problem back to ticking over just fine.

I did look for a gauze filter yesterday and it doesn’t have one. Spent a bit of time to find it. Have good clean fuel going in now. The old filter did have rusty watery crap in the bottom.

If you any one has a link to an electric pump could they post it. I haven’t a clue what I’m looking for really.

Going to get some diesel additive and put that into the pump. Some one I know thinks the governed could be stuck with crud not allowing it to rev.

Cracked injectors and diesel pushing out of them so it’s got to be a pump problem now.
 

manhill

Member
have you got a good flow of fuel when you bleed it at the pump, if so its muck in pump or faulty pump but doubt its that.> have a few 3 litre Isuzu and I always install an electric fuel pump (£20 off ebay ) as it makes life so easy.
if it's not working with direct feed to the injector pump why would an electric fuel (lift) pump make any difference?
The fault has been isolated to the injection pump side of things now.
 

Deutzdx3

Member
Rightly or wrongly I just blew air up where the fuel line goes on. It has cleared what ever blockage. It reveals properly now. For how long I don’t know but I have done every thing to make sure the fuel going in is clean now.

I would go with an electric pump to take the place of the hand lift pump.
 

Cowcalf

Member
look on ebay for facet red top fuel pump £14 99 thats the one I have got on 3 troopers instead of sucking fuel your pumping it works well for me, also have see through in line filters ( quite big ones)
 

Highway star

Member
Location
North west
Id check to see if it has a start solenoid. Some Isuzu 2.8 pumps do. It allows fuel pressure to build up for excess fuel start pressure, then once running it opens and allows fuel to return to tank. It's abit like blocking off the leak off. If this solenoid has no power once engine is started u can't rev up
 
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Deutzdx3

Member
I’m pretty sure it’s the pump. It was running fine on the can on the wing. Put back into the fuel system from tank after checking all air tight. Put a gauge on one end and pressurised the line. Holds pressure.

Pump seems to be the issue. Thinking it might be blocked some where or governor not being allowed to open fully. It’s a head ache that’s for sure.
 

Highway star

Member
Location
North west
The solenoid is on the pump. There's usually two. One for stop, and the other for cold start. The cold start is the top one on the end of a banjo fitting with the injector leak off pipe going to it. What you need to do is connect a live to it when the engine is running then see if it revs up
 
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Deutzdx3

Member
The solenoid is on the pump. There's usually two. One for stop, and the other for cold start. The cold start it the top one on the end of a banjo fitting with the injector leak off pipe going to it. What you need to do is connect a live to it when the engine is running then see if it revs up

There is no power going to that solenoid. Since I’ve had the vehicle about a month it hasn’t been connected and worked just fine up until yesterday. I will put 12v on to it though to test it now. Will come back shortly.
 

Deutzdx3

Member
The solenoid is on the pump. There's usually two. One for stop, and the other for cold start. The cold start is the top one on the end of a banjo fitting with the injector leak off pipe going to it. What you need to do is connect a live to it when the engine is running then see if it revs up

Ok,

Connected that up to the main 12v supply that goes to the shut off solenoid. Works a treat. Revs perfectly. Currently running off a can. Plumb the lift pump back onto the fuel inlet on the pump and no fuel coming out. Think the disphram is sucking air in. I can’t even prime it and get fuel through.

Next question, should that solenoid have power to it all the time when running or go off at some point?

Thanks for your help.
 

Highway star

Member
Location
North west
Yes this solenoid only has power when running! There should be no power to it on cranking either. Only once the engine is running, , it usually has a power feed from the alternator. Like I say it's to allow cold start by excess fuel. If the solenoid doesn't have power ie, dump the fuel the engine won't rev. It's a strange set up but works
 

Deutzdx3

Member
Yes this solenoid only has power when running! There should be no power to it on cranking either. Only once the engine is running, , it usually has a power feed from the alternator. Like I say it's to allow cold start by excess fuel. If the solenoid doesn't have power ie, dump the fuel the engine won't rev. It's a strange set up but works

I’ve had the vehicle for a month and it run fine and that’s not been connected at all. Will it use more fuel now or just the same as before do you know. Should I be looking to take a power feed from the alternator and linking it in?

I still can’t get it to run unless it’s on a gravity feed can. The lift pump wouldn’t pump fuel at all so have ordered a replacement as it has the spin on filter and ordered a red top electronic primer pump as well.
 

Highway star

Member
Location
North west
Yes any power only when the engine is running, so yes the alternator usually maybe via a relay. But not the stop solenoid supply as that has power when cranking. As for fuel I wouldn't know. Some times I think these engines will run for a short time without any power to this solenoid but they won't start again or won't rev. Japs sometimes have strange ways of doing stuff
 

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