nickwilliams Posted July 25, 2022 Share Posted July 25, 2022 I'm posting this for my brother, Simon, who has recently taken delivery of a Series 88in Station Wagon re-build project from my son, Zak. Simon has actually owned the vehicle since the 1970's and it's the vehicle I learned to drive in. However, it fell into disuse around 1985 or so and has spent the intervening years slowly dissolving away in a field. Then, a couple of years ago, Simon came to an arrangement with Zak for Zak to re-build it onto a galvanised chassis with view to getting it roadworthy again. To briefly summarise the (much longer) account below, the problem is that the engine runs for about 15 minutes and then stop abruptly. Simon has tried lots of tests and substitution of bits such as the injector pump but none of them have made any difference. We're now looking for ideas of what to check next. Here is Simon's account of the problem. ---------- 1. Background Land Rover Series 2A 2.25 litre 3 bearing crank diesel, vintage 1980 ish, rebored and new pistons. Bottom end unchanged at rebuild. Probably needs a new oil pump – oil pressure low (20 psi) with engine at running temperature. Engine is fitted in vehicle (88in station wagon). Reconditioned DPA pump fitted, timed using the recommended jig and the procedure as per the Rover instructions. Injectors checked and re-fitted as serviceable initially, though events superseded this and they have since been replaced. Coolant level in radiator is normal, oil level in sump marginally low (but needs replacing). 2. Symptoms Engine starts OK, not eager and needs heater plugs but then it always did. Copious blue smoke clears after 5 mins or so. Runs at idle for about 10 mins then you can hear the idle speed slowing. Over the next five minutes or thereabouts idle gets slower and some black smoke from the exhaust. If you rev the engine with the throttle during this phase the engine revs rise very slowly despite snapping the throttle open (poor throttle response), when you let go again the idle speed is lower until it eventually peters out. Engine stops abruptly as if it has seized (no compression bounce). As quick as I can insert the crank handle and turn the engine with no evidence of seizure. Cylinder head temperature is 70 to 80 deg C measured with non contact IR meter. During the latter stages of running the engine loosening the fuel feed banjo at the DPA pump shows a shower of fuel, there is no evidence of lack of fuel. I have fitted transparent pipes to the fuel supply, no bubbles. Engine will restart though reluctantly – needs a lot of throttle to keep it running. Allow engine to cool back to ambient, then engine will restart exactly as per the above, idle for the same time, shut down in the same way. Absolutely text book fuel starvation! Except there is plenty of fuel at the DPA pump top banjo. Driving the vehicle shows normal level of power for the first five mins or so after start, then rapidly diminishing until the vehicle won’t propel its own weight (low ratio on level ground!), then the engine dies as above. 3. Investigations/activities tried so far - Advanced injection timing. Initial setting as per setting gauge sounded retarded, so DPA pump advanced till it sounded right. Improved the initial start up, also reduced the quantity and length of time blue smoke emitted from exhaust. May have contaminated the engine oil with diesel fuel running it with the original setting for the injection timing. Injector 4 not contributing (much) to running – exhaust manifold at cylinder 4 cold for several minutes after start. - Checked fuel pick-up pipe in tank for leakage/blockage. Nothing to see. Fuel tank is open to atmosphere. - Changed fuel pipe from pick-up to lift pump for flexible hose. No change. - Changed fuel filter. No change. - Re-piped fuel lines looking for obstructions. Checked connections are exactly as per published diagram in the work shop manual. Fitted transparent piping looking for air bubbles. Nothing. - Swapped engine mounted fuel lift pump for electric one. No change. - Reverted to mechanical pump. Measure fuel delivery pressure at fuel filter outlet, steady at about 2 psi unchanged as the engine slows and stops. Obviously this pressure collapses once the engine has stopped. - Swapped rebuilt DPA pump for another of indeterminate parentage (ebay purchase). Set the injection pump timing (position) as per the pump taken off. No change. - Check cylinder compression pressures cold and hot. Results as follows: Cold 1 = 23bar, 2 = 31 bar, 3 = 30 bar, 4 = 24 bar. Hot 1 = 23 bar, 2 = 30 bar, 3 = 29 bar, 4 = 26 bar. So effectively unchanged. Cylinder head temperature (IR probe) measured 20 degC cold, 85 degC immediately after engine stop. Pressure checked by removing all four heater plugs, and connecting the compression tester with an adaptor into each glow plug port in turn. - Removed exhaust and inlet manifolds check for obstructions (rag?) Nothing to see. - Ran engine with exhaust loose at exhaust manifold (is the exhaust blocked?) No change. - Checked injection pump actual timing. I bought a Gunson piezo sensor based adaptor to trigger a timing light from the injection pulse. This showed the engine running solidly at about 12 deg BDC injection start, not 15 deg as per workshop manual, measured at tick-over. As the engine heated up and slowed the light flash got less reliable, though what flashes it did trigger showed the injection timing didn’t change as the engine slowed. Not sure if this shows the sensor/trigger operation is not 100%, or is this evidence of a poor injection pulse (indicating no fuel?) - Changed all four injectors for reconditioned ones. Testing of the originals elicited the comment that 3 was OK, 1 and 2 were “not the best”, and 4 was useless. Fitting the replacements made the blue smoke emission immediately after start better (less of it) and for less time, but has made no difference to the engine shut down after about 10 to 15 minutes. - I have a minor leak on the injector pipes 2 and 4, but slackening any injector pipe causes the engine to run rough and slow. Exactly as one would expect. Haven’t tried this with the engine hot and slowing. - Removed thermostat capsule hoping to prevent engine heating up. No change, though the measured cylinder head temperature was much the same at engine stop as with thermostat fitted. - Ran engine with radiator cap removed. Plenty of coolant circulation, no evidence of bubbles at the radiator header tank. Engine stops after 10 – 15 mins exactly as above. 4 Suggestions for Further Work My understanding is that it is possible to measure the DPA pump transfer pump fuel discharge pressure by removing a blanking bolt on the side of the DPA pump. If the DPA pump is being starved internally this could cause the symptoms seen. But how come I have two the same? Can anyone confirm how to do this and that the bolt opposite the body bleed screw is the right measurement port? Would need to make a special banjo fitting – no problem. - Take cylinder head off, looking for evidence of scuffing in the bores pointing towards momentary seizing. It’s an expensive experiment when I have no real evidence of seizure. - What are symptoms as of a cracked cylinder head? Note no evidence of bubbles in the radiator whilst running or water contamination of the engine oil. - Engine breather generates considerable fumes once it reaches running temperature. I can’t see why this should cause it to shut down, but any thoughts? ----------------- I'm of the view that this problem need solving by measuring various parameters such as fuel delivery pressure, injection pressure, exhaust temperature etc until we understand exactly what's happening when it stalls. It's not going to be cured just by swapping bits until it works properly. So, suggestions of what to measure and why it would help would be welcomed. We'd welcome any further ideas for things to check, or any other insight! Quote Link to comment Share on other sites More sharing options...
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