jrjackso Posted November 18, 2013 Share Posted November 18, 2013 Looking for some advice on proper cold start for my 86 Defender. Looking thru the forums it looks like proper cold start procedure is Do not touch accelerator !!! Give it glow plugs 10-15 seconds Turn over It's really not that cold out, following behavior has been seen 50-70 F. If I follow the above, usually within 2-3 seconds of turn over it will fire, but will not stay running. Even if i try again and again, it will fire, but never stay running. If vehicle has been running it will fire right up. When cold, if i give it some throttle, or better yet, pull the idle adjustment plug (whatever the right term is) out to the first or second slot, it will then start and stay running. However, it looks like both the throttle cable and this fast idle adjustment plug (just right and above fuse panel) just hook to the same throttle assembly on the fuel pump. So my questions are 1. Using the fast idle adjustment will disable the cold start mechanism in the fuel pump, and therefore shouldn't be touched till after vehicle has started ? 2. Is this a sign that the cold start in my fuel pump is not working, or possibly something else ? thanks jeff Quote Link to comment Share on other sites More sharing options...
Landowner Posted November 18, 2013 Share Posted November 18, 2013 Don't use fast idle (hand throttle) this will disable cold start mechanism, its just like pressing the accelerator pedal Do dash lights go dim when holding heater plug position on key, maybe not turning it far enough Quote Link to comment Share on other sites More sharing options...
jrjackso Posted November 18, 2013 Author Share Posted November 18, 2013 That's what i figured on the hand throttle. Not sure if dash lights dim, will have to watch more closely (I assume so), but glow plug light on warning panel lights up and dials fall back to zero. I also hooked up test light and plugs getting current. I pulled each glow plug and direct connected them to a power source and each glows after about 5-7 seconds. Has anyone seen plugs be a problem even if they appear to function? They appear to be a pretty cheap item to replace new. I had no idea how old the original battery in the vehicle was and appeared to not have much stamina. It was also rated at 650 cranking amps. So i replaced with a 950 cca commercial battery, which really turns things over easy. So battery should be good as well. Quote Link to comment Share on other sites More sharing options...
Landowner Posted November 18, 2013 Share Posted November 18, 2013 That's what i figured on the hand throttle. Not sure if dash lights dim, will have to watch more closely (I assume so), but glow plug light on warning panel lights up and dials fall back to zero. I also hooked up test light and plugs getting current. I pulled each glow plug and direct connected them to a power source and each glows after about 5-7 seconds. Has anyone seen plugs be a problem even if they appear to function? They appear to be a pretty cheap item to replace new. I had no idea how old the original battery in the vehicle was and appeared to not have much stamina. It was also rated at 650 cranking amps. So i replaced with a 950 cca commercial battery, which really turns things over easy. So battery should be good as well. Even on the coldest of mornings mine always started first turn, I held heater plugs on and counted one and two and three etc up to ten and she fired up. Lumpy at first with smoke until I gave it a little rev then the smoke cleared and she settled down to tickover. I took the engine out Saturday ready for a 200tdi, hope its as reliable as the old 2.5 n/a Quote Link to comment Share on other sites More sharing options...
Snagger Posted November 18, 2013 Share Posted November 18, 2013 I think you have a fuel problem, not a heater plug problem - the plugs help it start, but you already get a start up. Heater plugs will also help a cold engine run more smoothly for the first few seconds, but should not make the difference between running and dying in a healthy engine. Is your fuel filter clean? I suspect that or a small air leak into the system. Quote Link to comment Share on other sites More sharing options...
Landowner Posted November 18, 2013 Share Posted November 18, 2013 I think you have a fuel problem, not a heater plug problem - the plugs help it start, but you already get a start up. Heater plugs will also help a cold engine run more smoothly for the first few seconds, but should not make the difference between running and dying in a healthy engine. Is your fuel filter clean? I suspect that or a small air leak into the system. +1 for above, could be leak off pipes between injectors Quote Link to comment Share on other sites More sharing options...
jrjackso Posted November 18, 2013 Author Share Posted November 18, 2013 I had found and fixed one fuel system leak (asked in another forum thread) and things had gotten better. A new fuel filter seems like an easy thing to try as I don't know how old the one in there is. Quote Link to comment Share on other sites More sharing options...
Landowner Posted November 18, 2013 Share Posted November 18, 2013 I had found and fixed one fuel system leak (asked in another forum thread) and things had gotten better. A new fuel filter seems like an easy thing to try as I don't know how old the one in there is. Lift pump could be getting tired as well Quote Link to comment Share on other sites More sharing options...
Eightpot Posted November 18, 2013 Share Posted November 18, 2013 As above, but also check the idle adjustment - sometimes the idle speed gets adjusted using the throttle cable or throttle mechanism which then cancels the cold start - rather than using the idle screw. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted November 19, 2013 Share Posted November 19, 2013 I didn't know the 2.5 n/a throttle operation (either by hand or foot) affected the glowplug operation as its a mechanical fuel pump etc? on my 86 ex mil you only had ignition position 1 then a springy bit (glowplug manual) then pos 2 for starter to kick over. Once started it springs back to position1. The only electrical connection on the fuel pump is the stop solenoid. It may be worth changing the glowplugs though, they are small/cheap enough to have shipped if you can't find them locally. You can check my switch theory by clipping a 12v bulb and flylead one side to any of the glowplugs and the other side to the engine block (earth). HTH Pete Quote Link to comment Share on other sites More sharing options...
Eightpot Posted November 19, 2013 Share Posted November 19, 2013 I didn't know the 2.5 n/a throttle operation (either by hand or foot) affected the glowplug operation It doesn't, it affects the mechanical cold start mechanism inside the fuel injection pump Quote Link to comment Share on other sites More sharing options...
jrjackso Posted November 21, 2013 Author Share Posted November 21, 2013 I checked the throttle cable. Linkage appears to be resting against the idle screw. How does the fuel pump "know" it is at idle; i.e. against the idle screw. How does it tell the difference between idle dictated by the throttle cable versus adjusting the idle screw? Quote Link to comment Share on other sites More sharing options...
Landowner Posted November 21, 2013 Share Posted November 21, 2013 I checked the throttle cable. Linkage appears to be resting against the idle screw. How does the fuel pump "know" it is at idle; i.e. against the idle screw. How does it tell the difference between idle dictated by the throttle cable versus adjusting the idle screw? If you back off the throttle stop (throttle cable) the engine should still tick over (idle) nicely, if it dies then its set wrong. With cable disconnected set the idle with the idle setting then connect cable. Quote Link to comment Share on other sites More sharing options...
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