Neuson Lifton 1501 dumper starting problems

[Bobthebuilder]

Hi everyone I'm new to this forum and hoping someone out there may be able to help. I have a Lifton Neuson 1501 hi tip dumper (year 2005) which I've had from new. It has never started we'll (except when it was new), but it is now worse than ever. Some times you have to crank the engine for 10 seconds before it will start and sometimes need a second attempt. It also seems to need pre-heat, even when starting from hot. Recently I have noticed it seems very slightly under powered when moving a load. The fuel filter and water separator have been cleaned (not replaced yet - new ones on order) but the air filter is a new one (as are the glow plugs incidentally). The battery is good and throws the engine over with enthusiasm. I have investigated a fuel starvation problem and although fuel appears to be getting to the injector pump ok, the amount of return fuel (excess) returning to the tank seems low - it is only a dribble (regardless of engine speed) and I'm surprised it is not a lot more but don't have experience in this regard. Should it pour out through the return pipe? Can any one offer any advice here.

[Muz]

Hi and welcome ..... does it need the throttle full down and runs really rough initially after starting when its cold, then settles down ?

[Bobthebuilder]

No, when it starts it seems to run ok, it just takes an awful lot of cranking.

[Bobthebuilder]

Ye-ha. I've found it and the problem all centres around the fuel shut off solenoid and the security system I had fitted many months ago. This dumper (Neuson 1501) has a fuel shut off solenoid with two coils, one high current 'pull in' coil controlled via a 2 second timer circuit and a low current coil used to hold the solenoid in after the high current coil has done its stuff (fairly standard I think). The security system, amongst other things, interrupts the low current 'hold in' supply but today I noticed that it didn't always appear to do this. This particular security system works by requiring the ignition key be turned to the first position (ignition on) before allowing you to perform the remaining disable process. It never occurred to me however (or presumably the security installer), that by the time the security was deactivated in this way, that the 2 second pull in current would normally have turned off by the timer. Thus simply turning the ignition key further to crank the engine will not start it because 'pull in' supply has been and gone. Ahhhhhrrrr!!! As the security device does not re-enable for 15 seconds or so after the ignition is turned off, all that is needed (following the disable process) is a quick turn of the ignition key to off, and then back on, to provide the short pull in supply the solenoid needs. None of this was ever explained of course by the installer and you can imagine that as the key was sometimes turned fully off when the engine failed to start, there appeared to be a somewhat random behaviour to add to the confusion. This explains the difficult start and I think a clean fuel filter will restore full power again - I'll let you know! So after hours of working out how the dumper was intended to work and then how the security device interrupted it, I now know how it all works and wish I had done the security install my self.

[Muz]

Thats good youve got it sorted .. but .. see if you'd started your first post, or mentioned that you had an anti theft system recently fitted .. that might have taken us down a whole different route !!

Anyways .. I'm surprised at there being any timers fitted to the FCO solenoid, normally the pull coil is simply energised while the engine is running, and lets go at shut off. The timer(s) are usually for the glow plugs, so they only stay on for a set period.

I take it its a yanmar engine ?

[Bobthebuilder]

Yes, its a Yanmar engine. There are 2 timers on these dumpers, one for the glow plugs and one for the fuel shut off solenoid. Both are housed in the control box under the engine cover along with the regulator and several other relays. Interestingly, the relay used to power the high power side of the solenoid via the 2 second timer is driven by a big chassis mounted relay with a label on the side saying 'glow plug relay'. This could throw you completely off track cos it is not used for the glow plugs at all!!! The solenoid gets quite hot sitting there (tested off the engine) even with just the low power coil on, so clearly the idea is to extend its life by dropping the current back once it has pulled in. The low power coil will not pull the solenoid in by itself - I tried this on a battery off the machine when I was trying to figure out what the hell was going on here !!! I thought this was all fairly standard on plant but you appear to be indicating different.

If I thought I could rely on my guys flicking a 'hidden' security switch at the end of the day, I'd have such a switch in preference to my current overly complex alternative any day of the week. Trouble is that I can't trust em. They even leave the keys in the thing!!! Rant over! Well, I tell you what, I know the electrics on these things backwards now. So, on to the next project now. A Manitou MT932 telehandler that doesn't always engage in reverse when you move the travel selector.

[Muz]

Very interesting Bob .. thanks for sharing your findings I have had a good few dumpers from this stable and their previous owners over the years but never come across this particular issue .. not sure I can help on the Manitou.. but as always fella, sometimes its good to just post and test someone elses logic .. and theres a good few of us here might come up with something for you.... hec just post the story and mission in stages, and I'm sure we can help

[Bobthebuilder]

Muz, whilst my dumper is now running OK, I really want to find an answer to an earlier question I raised and that is 'what is the normal amount of return fuel you would expect to see going back to the tank'. As mentioned, mine is a tiny trickle on tick over and sweet FA when the engine is running flat out. Now you probably wonder why I'm pushing this one. Well let me tell you. My security device interrupts the fuel line (as well as the solenoid discussed earlier) but in doing so the installer has significantly increased the length of the pipe. Return fuel is basically the excess that the injector pump does not need right? So if I have none spare when the engine is flat out, there is no margin right? I'm a bit concerned that whilst all is well now, that with just a mildly dirty fuel filter the engine may be inadvertently starved because of the increased resistance from the longer pipe. You or someone else out there must know the answer to this. I perhaps should add that I am checking this by removing the screws around the tank filler so that I can peer inside the tank easily and look at the return port coming in at the top of the tank. PS. Start the Manitou on Saturday!!

[Muz]

I'm not unduly concerned by your observations .. a steady trickle at tickover is normal .. and quite good in frosts infact, because it warms the fuel in the tank a little and prevents waxing during use.

THe lengths of fuel lines wouldnt concern me particularly either .. injection pumps operate at very high pressures on delivery , and have a mechanical waste expulsion process so .. that aint a problem.... however .. you should always pay particular attention to having clean filters for fuel intake .. that is a must

People ( in general) often see diesel as a dirty fuel , but , it isnt .. you will keep your engine running cleaner for longer .. make it start easier, and produce its most power by always making sure the fuel is as clean as it can be