JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

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stevejcb
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JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #1 by stevejcb » Thu Jun 11, 2015 6:23 pm

Hi everyone,

Back again with some problems to my 1980 jcb 3cIII.

When recently using my excavator, I noticed that the engine became more difficult to start from cold (better when hot, but not so willing) and there was an increase in blacksmoke. Over the course of a few days the smoke worsened and to get the movement of the all the hydraulics to function without the engine dying I had to increase the revs (usually idle does most of what I need, including driving.

Thinking that the loss of power was due to fuel sediment, I drained the tank again, and cleaned out the fuel pump filter - which was clogged. With the filter cleaned and the inlet and outlet pipes blown clean (detached first from the sediment end, I then stripped the sediment filter off, replaced filter and replaced supply line to pump with new one. System was then bled.

With the system clean the problem still persists (I have not removed or cleaned the injector pump as this pulsed the fuel from the union ends and seems okay.)
I have replaced engine oil and oil filter, topped up hydraulic system and torque convertor fluids.
Today, It took 2 minutes for the engine to fire and hold (starter motor wont last long at this rate). Lowering the jacks, moving the actuator(boom and bucket, scoop at the front - infact anything - caused the engine to lose revs and die - you can hear and feelthe engine not running smoothly as though its misfiring. With the engine revs higher, I attempted a trial dig, only to be rewarded with a burst hydraulic hose - I dont think this was related though.

I wonder what what could be causing my problem - is it a blocked injector? A blockage in one of the feeds from the injector pump, though they all seem to pulse fuel okay and its passing it clean? Is there something else, I've missed? :dizzy:

Thoughts please. Steve


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #2 by philwheelton » Thu Jun 11, 2015 11:56 pm

Could try the air filter


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #3 by hubert » Fri Jun 12, 2015 10:05 am

I agree. Sounds like filter is blocked.


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #4 by stevejcb » Fri Jun 12, 2015 4:33 pm

Hi, guys.

I thought so too and removed the air filter and throughly air blasted it, and cleaned casing and made sure that the tubes are clear to the manifold.

Do you or anyone else think that my problems maybe due to a blown head gasket? Is there a method I could tell other than by a full oil pressure test? its just a thought.


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #5 by Jeremy Rowland » Fri Jun 12, 2015 10:03 pm

stevejcb wrote:Hi, guys.

I thought so too and removed the air filter and throughly air blasted it, and cleaned casing and made sure that the tubes are clear to the manifold.

Do you or anyone else think that my problems maybe due to a blown head gasket? Is there a method I could tell other than by a full oil pressure test? its just a thought.


Two simple things to try before you start to rip the motor apart; remove the air filter element and run the engine again without the air filter; then that rules out any issues with the actual element which you cannot always blow all of the muck out of.
Then if that does not work when you have the engine running and warmed up; slack off in turn each injector pipe, if the engine stalls or runs rougher then you know that the injector on that cylinder is running okay, if nothing happens then you could have a dodgy injector.
Another daft problem but simple to check is the valve clearances; to be fair from what you have put my thoughts are that you may have fuel injection pump issues but I am second guessing here.
If your head gasket had blown the motor would overheat and the cooling system would pressurise and blow out the coolant.
Just a few ideas to try and help you.

Jeremy


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #6 by stevejcb » Sun Jun 14, 2015 10:16 pm

Hi,

I was finally able to get my hands on the digger again now that the rain stopped - so what did i discover?

I took out the air filter (completely accept the point about trying to clean it, when one should discard it) started digger, no difference in the running problem.

Next, I removed all the fuel pipe unions to check again, that each was pulsing clean fluid at the same rate - no problems there. I then reconnected, started engine again and began loosening each in turn. Starting from the rear, as soon as I loosen it half a turn the engine immediately stopped. On the third one (second from front) loosened the union, considerable more spray, no engine difference, so much so that I could remove supply altogether - this then appears to be the culprit, an injector that for some reason, whether faulty or blocked, wasn't working. However, I tried the last (or the first - not sure which is which) and discovered this also had the same outcome, ie: the engine continued uneffected. So it appears that i have two faulty injectors and the engine is lumpy because its only firing on two (I presume?).

My question now is, can the injectors be cleaned by myself (for I feel both can't have failed simultaenously, but just become blocked). The manual suggests this can't be done without specialist equipment? Thoughts please.


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #7 by philwheelton » Mon Jun 15, 2015 12:01 am

if you have two cylinders next to each other not working the head gasket could be blown between them and not affecting the cooling system.


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #8 by agrimax » Mon Jun 15, 2015 12:15 am

Steve,Number one is always counted from the fan end of the engine and from your last post it would seem that no.s 1 and 2 are not firing?It does sound like phil's suggestion that the gasket has blown but first I would suggest removing the 4 injectors and reconnecting them to the pipes upside down,in the same order they came out. Crank the engine and see which are giving a good even spray pattern. (Don't breath in the fumes.)You might have two good and two bad.Then swap them about.ie a non spraying injector onto a pipe that was giving a good injector a good spray before.If still no spray,then you can be sure those two injectors are faulty.The nozzles could be blocked or the needles seized/stuck. You will need to take all four to a specialist for an overhaul,not just the two.


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #9 by Jeremy Rowland » Mon Jun 15, 2015 7:42 am

agrimax wrote:Steve,Number one is always counted from the fan end of the engine and from your last post it would seem that no.s 1 and 2 are not firing?It does sound like phil's suggestion that the gasket has blown but first I would suggest removing the 4 injectors and reconnecting them to the pipes upside down,in the same order they came out. Crank the engine and see which are giving a good even spray pattern. (Don't breath in the fumes.)You might have two good and two bad.Then swap them about.ie a non spraying injector onto a pipe that was giving a good injector a good spray before.If still no spray,then you can be sure those two injectors are faulty.The nozzles could be blocked or the needles seized/stuck. You will need to take all four to a specialist for an overhaul,not just the two.



Yes I agree on all points; must add here do not get near the fuel injector while testing it out of the engine, the spray mist can pass straight through your skin so keep a fair distance from it. At least you are now along the right lines.

Jeremy


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Re: JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

Post #10 by stevejcb » Mon Jun 15, 2015 7:50 pm

Hi,

good points and warnings - I've heard that testing injectors can prove lethal. Couple of things before I try testing each one - if the head gasket has gone between no 1 and 2 would this have caused the failure of the injectors ie; from coolant? Would, if the gasket was blown cause detrimental problems in the short term ie: so long as I didn't run the engine for long, and if the head gasket was blown, is this a relatively easy job to replace without masses of specialised tools, specialised knowledge and specialised resetting of cams/timing etc?

Also mentioned that all 4 injectors would need servicing, i saw some cav injectors advertised on ebay as new ex military stock for bedfords, surely these would match?

steve


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