Thread: I resolved my TD5 Auto engine misfire

I Have an Auto TD5 2002 Discovery 2. Recently, after just clocking up 150,000 k's, it developed a misfire at 2000 rpm. This was on long inclines and just before revs dropped to force a change down to 3rd. It also occurred at idle and Park/Neutral. It could be avoided at the higher revs by braking below or accelerating above where possible. On my return to Charters Towers from the Palmer River I found the fault getting worse at the lower range [700 rpm]. Having read years of forum postings on the subject, and many of the manuals 1600 pages, I realised that I couldn't just do what others were doing and replace components until I fluked a repair as I am fiscally downsized at the moment. Also no one had appeared to find a solution from the many things tried.

I rationalised that a misfire had to relate to incorrect combustion which meant looking at what influenced fuel/air issues. There had been minimal mentions of sensor faults so I focused on those thinking that the ECM was getting, or sending, incorrect messages. Narrowing it down to crank case sensor or EUI's I soon ruled out the CKP Sensor. Taking notice of many mentions of oil in the harnesses, and oil on the 'pins' plus ECM red plug I checked the latter and found minimal oil, but oil just the same. Cleaned this out with CRC Contact Cleaner and tried again. Fault still there. Changed the MAF sensor but no difference.

Removed the rocker cover and looked in amazement at the sight of so much oil over the harness and injector solenoid multi plugs. Totally separated the plugs and cleaned with CRC Contact Cleaner as they were fully saturated internally with oil. Whatever happened to keeping fluids away from electrical connections?? Reassembled the parts and started up......Well bugger me the jolly thing ran like a swiss clock, no misfire at any rpm rangeand sounded so smooth.

Went for a short test run and not only did it perform like a Porsche [presumably smooth] but it no longer had the 7 year issue of intermittent sluggish initial acceleration, zapping away from the start which nearly caused an accident it was so unexpected.

This morning I took it for a longer test run and it was even better, so smooth and powerful I was staggered and idling was now 500 rpm not the 700 it had been for so long. So this worked for me and I hope by posting that it may work for others as I am not claiming to have the magic bullet for all. I will now do the clean regularly, perhaps six monthly, and keep hoping that it will remain fixed.

I have been 'lucky' enough to have gone through the '3 Amigos' which became 5. Fitting a new Modulating Valve made no difference and I have driven since 2006 with them and it is not a driving issue for me. I 'luckily' then got the 'M & S limp home thing' which the installation of a $1000 Limit [xyz] Switch fixed. The only other thing not yet corrected is the 'split second speed reduction and reinstatement' thing but on the next longer drive perhaps this is now ok? [it mostly occurs while in cruise control after approx 100 or so k's.

So I am hoping that this resolution that worked for me may work for others. I don't claim to have found the magic bullet. The hundreds of posts I read helped me to this conclusion, as did my fiscal imbalance, so I am thankful for the efforts so many put in.

Thanks. It should be fine on mine. Looks like some red sealant was used too.

I guess the trick is just be clean.

Are the cheap supercheap torque wrenches ok to go with?