pavman Posted January 8, 2013 Report Share Posted January 8, 2013 I am working on my 1986 Diesel Case IH 685 and have sorted most jobs apart from the starting, just now it will only fire up with cold start... I have fitted new filters and a new heater plug on the inlet manifold and wired it to a new relay and switch and it works fine, the problem being its not getting Diesel in a hurry. The Diesel comes from a tee off the return line from the injectors which also returns to tank and the top of the injector pump. The idea is the plug heats opens a port and diesel is ignited assisting cold starting.... If i crack the compression union to the feed on the heater plug on cranking no Diesel is there unless the engine is running, i have replaced the return lines between the injectors and checked all fittings for tightness as it looks like the diesel is perhaps falling back down the line so is not there when starting. Now i was expecting to find a lift pump between tank and filters/ injector pump to look at next but so far have not, perhaps i have not looked hard enough??? could it be in the tank (i thought they ran off a crank arm) any ideas welcome Quote Link to comment Share on other sites More sharing options...
richie223 Posted January 8, 2013 Report Share Posted January 8, 2013 Could be a hair line crack/faulty fuel filter head,causing fuel to drain back to the tank or perished fuel lines dragging in air Quote Link to comment Share on other sites More sharing options...
firdom Posted January 8, 2013 Report Share Posted January 8, 2013 If memory serves me well there is an excess full button on the injection pump activated by the stop control you pull the stop control out until you feel a resistance that is excess fuel activated heat for 20 or so seconds then start . So stop control has 3 settings forward =run. right back =stop. position just before stop button=excess fuel should only need heat when very cold hope this helps was a long time ago when i worked on one Quote Link to comment Share on other sites More sharing options...
pavman Posted January 8, 2013 Author Report Share Posted January 8, 2013 Guys thanks and yes I do as you state for excess diesel but its not getting there for a long time Quote Link to comment Share on other sites More sharing options...
Gordon R Posted January 8, 2013 Report Share Posted January 8, 2013 I have very limited experience with diesels, but had a similar problem. Turned out to be poor injector seals. Fuel was returning to the tank and the engine had to be cranked a fair bit to drag fuel back through. Quote Link to comment Share on other sites More sharing options...
Bazooka Joe Posted January 8, 2013 Report Share Posted January 8, 2013 Same happened with me a few years ago with a diesel pickup I had, to stop the diesel running back to the tank I put a one way valve in the fuel line, worked a treat. Quote Link to comment Share on other sites More sharing options...
bedwards1966 Posted January 8, 2013 Report Share Posted January 8, 2013 I'm a little unsure - is the problem that you aren't getting fuel quickly to the heater, or that you aren't getting fuel to the injectors? If you aren't getting it from the return line to the heater installed in the inlet manifold, this is because they are designed to have a reservoir ready to supply fuel to the heater. I don't how it would be laid on on a 685 but is needs to be so that there is a supply of fuel from the reservoir without the engine cranking over (it must flow easily). The heater is held on for 15-20 seconds then the engine is cranked. Quote Link to comment Share on other sites More sharing options...
Sx3 clay breaker Posted January 8, 2013 Report Share Posted January 8, 2013 Could be injectors shaged or crud in the tank Quote Link to comment Share on other sites More sharing options...
pavman Posted January 9, 2013 Author Report Share Posted January 9, 2013 I think the return to tank idea is a contender a non return valve may be the answer, i have found there is no lift pump on this tractor so it must be integral in the injector pump so it sucks it through and a leak back to tank means it takes a fair bit of cranking to get it there and as the heater plug works off the excess fuel from the injectors it takes an age for the heater plug to get any to fire up..... so where is the best place to fit a non return, i have hardish plastic push fit pipe from the tank to the filters the rest is hard line Quote Link to comment Share on other sites More sharing options...
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