Marten Posted October 26, 2013 Share Posted October 26, 2013 After 230K miles it seems my Turbo is showing it's age! Perfect idle, but loss of power and surging above 1500 rpm. Fuel supply to Injector pump was the suspect, and this seemed likely when I found the lift pump inlet non-return valve was leaking back, but now proved good after hours working back from the in-tank unit to the Injector pump inlet, changing fuel lift pump and fuel filter, checking coalessor and pressure testing fuel lines (which were replaced with hard plastic 24K miles ago). Good flow now from the lift pump (via filter air bleed screw) at high revs. I'm hoping the Injector Pump is not the source as the low rev performance is fine and exhaust is clear of smoke at all revs, even when surging at higher speeds. Engine was fully re-built 24k miles ago and performance has been good until this problem recently arose. I have yet to visually check turbo rotation at rest and measure boost pressure when running (when I get a suitable tee connector) but I get no movement at all of the waste-gate servo when revving hard (albeit very un-evenly at present). I can move the waste-gate link arm with a spanner. It is quite hard to turn against the servo spring, but the movement is smooth. Question; What is the purpose of the pressure sensing line that connects the Turbo output to the Injector Pump? This line is not leaking, but I am wondering just what the purpose is of this pressure supply to (a diaphragm?)the top of the Injector Pump. Would a failed diaphragm cause my problem if the Turbo proves to be good? I'll be grateful for typical Turbo failure symptoms and info regarding the line to the Injector Pump. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 26, 2013 Share Posted October 26, 2013 You won't see the waste gate move until you put the engine on load. Impossible to do without driving it. The line from the turbo to injection pump is for the fuel compensation diaphragm. On boost this moves allowing more fuel to be injected. Can you clarify what you mean by surging? Even with a stuck wastegate, you still shouldn't get turbo surge - it'll just go like stink! Turbos normally fail by making an horrendous noise as the turbine/compressor contacts the housing. Followed shortly by zero boost. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted October 26, 2013 Share Posted October 26, 2013 Surging is something I would normally look to fueling as it would be over or under,over fueling giving tell tale smoke under just flat spots and no power. Quote Link to comment Share on other sites More sharing options...
steve b Posted October 26, 2013 Share Posted October 26, 2013 pop the diaphragm cover off and check the plunger in the middle of the rubber moves down freely and the rubber is still ok . It could also be delaminating intercooler pipes cheers Steveb Quote Link to comment Share on other sites More sharing options...
Marten Posted October 26, 2013 Author Share Posted October 26, 2013 The problem seems far more like fuel starvation, but I'm guessing the air starvation might have similar consequences, For about a week, the engine faltered at 50mph plus and I noticed that there was a slow increase in the revs needed to fire it up. It normally starts immediately and I have never used the pre-heaters. The faltering increased steadily down the speed range and I couldn't comfortably exceed 45mph prior to garaging it. I suspected a. a fuel line part-blockage, b. a fuel line split, c. the engine lift pump. The failure of the lift pump inlet non-return valve was promising, and certainly explained the starting delay as fuel was probably draining back to the tank, but replacing it didn't remove the higher rev problem. It now starts immediately! I continued to suspect a fuel problem and worked from tank to injector pump looking for air leaks or blockage, but nothing found. If I crack the injector pump inlet banjo at idle or high revs I get good fuel pressure. Ditto at the fuel filter bleed screw. Opening the throttle from a steady 900rpm idle, the engine speed increases, but in random increments, falling back and increasing again, sometimes rising rapidly (normal rate) and then after a short period of steady revs, faltering again and cycling up and down by a few hundred revs. It ceilings out at about 3000rpm and runs very irregularly. There is no mechanical distress noise and no significant smoke from the exhaust. It really is just like random fuel starvation. The injectors were serviced and tested professionally during the engine rebuild 24K miles ago but I have had the vehicle from new and the injectors are original, as is the injector pump. I am fairly confident the engine is in good mechanical condition with new pistons, valves, etc., etc. Fuel in the tank is good. Air & fuel filters are new. I'm left with the Turbo and the Injector Pump as unknowns, with a good steady idle as a base line. Quote Link to comment Share on other sites More sharing options...
Marten Posted October 26, 2013 Author Share Posted October 26, 2013 Further to my last I have run the engine with the intercooler to inlet manifold pipe removed. Perfect idle but same symptoms at higher speeds! Quote Link to comment Share on other sites More sharing options...
Tanuki Posted October 26, 2013 Share Posted October 26, 2013 I'd definitely check fuel delivery to the injection pump: if there's a restriction in flow, or air getting in, you'll get surging under load. It's not unknown for the metal pick-up-pipe on the tank to get holed by rust allowing air in; similarly if there's a strainer on the end of this pipe inside the tank, it can get clogged with rust from the tank or a horrible jelly-like goo if you've ever picked up any water-contaminated fuel. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 26, 2013 Share Posted October 26, 2013 That sounds very much like either a fuel or governor issue. If you can replicate the symptoms without having to drive it, then it's not turbo related (or at least highly unlikely) If you're confident that it's not fuel, then it's time for an injection pump overhaul. You can I believe, get at the governor mechanism without having to remove the pump. It might be worth taking the top off to inspect inside....if you're brave. Quote Link to comment Share on other sites More sharing options...
Marten Posted October 26, 2013 Author Share Posted October 26, 2013 Thanks Folks! It all helps! I'll have no opportunity to progress the diagnosis till Monday, but will cover all the points raised then and report back. I'm quite willing to strip the Injection Pump if necessary, but in my previous life as an RN Marine Engineer I had the facilities to set the pump up correctly. I'm not far North of Inverness, so may be able to find a suitable specialist to correct any problems I find and re-calibrate the pump afterwards. Quote Link to comment Share on other sites More sharing options...
Marten Posted October 28, 2013 Author Share Posted October 28, 2013 Turbo appears physically undamaged and wastegate actuator moves full travel when 12psi applied to hose connection. At a faltering 3000rpm on a shallow hill the boost pressure is 7psi max.(Book says 11.3psi max). All air and fuel hoses undamaged, clear and no leaks. At full throttle, engine runs irregularly at 3000rpm max cycling up and down by 100/200rpm. Does this stationary and on the road. No smoke from exhaust under any condition. Still a perfect idle at 900rpm. Engine runs up to about 2000rpm smoothly and will hold that speed with a slight tremor in revs. Moving the throttle, say 10%, further open gets no response initially and then revs jump up to about 2500rpm and engine speed varies greatly. More throttle gets a gradual increase, but with a lot of random speed variation, to about 3000rpm but it will not exceed that speed! At this speed there is plenty of fuel pressure from the lift pump at the Injector Pump inlet banjo. I am inclined to think that the problem lies with the Injector Pump rather than the Turbo. Perhaps a governor problem? Any thoughts? Quote Link to comment Share on other sites More sharing options...
Nigelw Posted October 28, 2013 Share Posted October 28, 2013 Lack of boost could be wastegate actuator rod needing adjustment, the rest is pump related I am almost sure. Try swapping it over with a known good one and see how you get on. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 28, 2013 Share Posted October 28, 2013 Perhaps a governor problem? Any thoughts? Bingo I'd say. My first thought when reading the above. I think the lack of boost is a red herring. If you're not fuelling enough to spin the turbine then you'll be low on boost. If the wastegate is operating correctly, then it is unlikely to be this. Quote Link to comment Share on other sites More sharing options...
Boydie Posted October 31, 2013 Share Posted October 31, 2013 Inside the banjo connection on the FIP there is a tiny fine mesh filter - check that -- if its even partially blocked it will give the problems you seem to be having, clean it with compressed air and your problem is solved. Quote Link to comment Share on other sites More sharing options...
Marten Posted November 1, 2013 Author Share Posted November 1, 2013 Hmmm! No fine filter present in any of the fuel line banjo connectors on my early (1992) 200TDi. I am quite sure now that there is plenty of fuel available to the Injector Pump. It will be stripped tomorrow morning, so all should be revealed! It has completed 230K miles without any problems, so it may just have reached a tipping point! Quote Link to comment Share on other sites More sharing options...
Marten Posted November 2, 2013 Author Share Posted November 2, 2013 I think this particular thread has come to a conclusion! Top of the Injector Pump removed and whilst no sign of physical damage, the internals were liberally coated with aluminium particles, and some quite large deposits of same in various corners. I now know there is indeed a fine filter in the relief valve bolt and this was partially blocked with particles, but a thorough clean achieved nothing. There is clearly a significant wear problem in the lower regions of the pump and extensive contamination throughout. Will fit a replacement pump tomorrow and hope that this will restore performance. I'll strip the current one in slow time. Did coax the engine to 3000rpm on a long incline and turbo achieved a "steady" 12 psi so my initial fears of a turbo problem are unfounded! I'm off to make the "special tool" to hold the pump timing sprocket in place while I swop pumps! Cheers all! Quote Link to comment Share on other sites More sharing options...
Marten Posted November 4, 2013 Author Share Posted November 4, 2013 Replacement (used 300TDi pump) Injector Pump fitted and all running sweetly across the whole revs range. Turbo producing a steady 12psi at full throttle on an incline, so it may be good for another 230K miles. Can strongly recommend taking time to manufacture the "special tool" pictured in the Land Rover Manual to hold the toothed pulley in place whilst the pump is withdrawn and replaced. A bit of scrap 3mm plate shaped to match the front cover closing plate, two 8mm x 75mm bolts with heads cut off, screwed through the plate into the threaded holes in the pulley. 22 8mm washers on each bolt as spacers between pulley and plate and a washer and locknut against the plate on each bolt to hold it all tight. Plate secured to the front case with the 3 6mm screws used to secure the cover plate. Don't forget a 1/2 in hole to accommodate the pump timing pin! Replacement pump just slid into the pulley with no risk of timing loss or belt damage. Magic!! Just to be clear, the "fine filter" mentioned in my last post is in the bolt securing the fuel spill return banjo at the back of the pump. Quote Link to comment Share on other sites More sharing options...
AngusN Posted November 19, 2017 Share Posted November 19, 2017 I have just had the same problems, poor acceleration, only able to do 50mph and turbo not working. It was the injector pump, the governor springs had broke. I went on eBay and found a non genuine 200 TDS sprocket locking kit that was the muts nuts. Second hand pump fitted today and I now have my old Landy back to normal Quote Link to comment Share on other sites More sharing options...
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