This is getting bloody annoying...

**Leo109** · 28th March 2020, 10:03 AM

Hi All,
A few months ago I posted about 'Lady Daphne II' our 2003 EU3 Td5 auto's strange behaviour when trying to overtake. Basically it was running normally and strong in normal driving and provided you used gentle acceleration in 4th lock-up. But plant the foot at say 90 km/h to overtake and it kicks down a gear (or two), rpm go up but there's bugger all acceleration or even struggling to maintain speed up an incline.
Finally got around to pulling out the Nanocom and had these faults logged:

7,5 Turbo wastegate short circuit
7,8 Temperature gauge short circuit
20,2 Turbo overboost

So, I cleared these and did some more driving - with the same problems. Now the first two faults have not reappeared. This seems strange in itself as, in my experience, shorts circuits of just about anything don't fix themselves!
The overboost fault reappeared so, needing to do a 400km round trip to Brisbane, I wound the wastegate rod off 1 & 1/2 turns. Also cleaned the red plug on the ECU. Was a bit of oil around the lower 6 - 8 pins.
On the trip she behaved impeccably with strong overtaking power. Until we stopped at our PO Box on the way home... Went to take off up the slight hill leading out of town and she would barely accelerate at all from standstill. Pulled over for a moment and tried again. Performance back to normal - ?? Checked Nanocom the next day and no faults logged!
The odd behaviour has continued intermittently and I've since had another turbo overboost logged. As mentioned, this is getting very annoying.
I know this vehicle is getting on for 17 years old but after replacing the water pump, repairing the started solenoid, done the 'option B' fix for the Three Amigos and had the fuel pressure regulator replaced (after having the vehicle tilt trayed to British Off Road), it's starting to wear out its welcome. At 172,000 km it's proving to be nowhere near as reliable and robust as the 23 year old, 422,000 km 300Tdi 'Lady Daphne I'. And my good lady is starting to mutter the word "MUX" within DII's hearing...

**PhilipA** · 28th March 2020, 10:17 AM

I would be looking at the wiring loom to the modulator etc , just as it turns the corner on the LH front of the motor and maybe strip the insulation and look where the 2 steel keepers are across the front.
Regards PhilipA
Geez at 172KK its only a baby.

**justinc** · 28th March 2020, 11:23 AM

The possibly that you have a leak in the signal hose from the Pressure side intercooler pipe to the boost modulator is 1, also 2 ,check the boost modulator is actually working correctly, 3 the wastegate isn't intermittently mechanically faulty, like sticking closed.
The easy way to isolate the modulator is to bypass it and test drive. I would probably also check your max boost in instrument mode on the nanocom, should start to cut fuel at about 240kpa (absolute).

👍🙂

**Leo109** · 28th March 2020, 11:41 AM

Thanks Philip & Justin. You've given me a few things to check.

Stay safe everyone!

OT & PS: Justin, "Isuzu 110 - soon with an auto"? What slushbox have you decided to go with?

**sierrafery** · 28th March 2020, 02:26 PM

Also cleaned the red plug on the ECU. Was a bit of oil around the lower 6 - 8 pins.

Hi. First of all replace the injector loom then keep cleaning the plug untill all the residual oil leaves the harness cos you cant properly diagnose the rest while it's leaking, simply cleaning the oil without changing the loom is not enough and doesnt last.... maybe that's why it behaved well for a while after you cleaned it

**Leo109** · 28th March 2020, 03:12 PM

Originally Posted by sierrafery

Hi. First of all replace the injector loom then keep cleaning the plug untill all the residual oil leaves the harness cos you cant properly diagnose the rest while it's leaking, simply cleaning the oil without changing the loom is not enough and doesnt last.... maybe that's why it behaved well for a while after you cleaned it

Thanks for that. Yes, I have a new injector loom - just need to find the time to fit it and to flush through to the red plug. Will have to look up the current best practice for sealing the injector loom plug too. If anyone can post a link to the latest & greatest method it'd be much appreciated.
By the way, if oily plugs & sockets can lead to such dodgy behaviour, why are no fault codes logged?

**sierrafery** · 28th March 2020, 03:54 PM

The oil acts as isolator and affects the circuit's resistance without interrupting it completely so there are cases when the ECU keeps working with altered inputs which are within a range where no codes are logged but the engine's behaviour is affected. the same thing happens when a sensor is dirty but still working e.g. if the MAP sensor is gunked up there will be no codes but the engine will be sluggish... in your case those short circuit codes which were stored are worrying unless they were hystorical but he injector loom must be changed anyway

**justinc** · 28th March 2020, 04:02 PM

Originally Posted by Leo109

Thanks Philip & Justin. You've given me a few things to check.

Stay safe everyone!

OT & PS: Justin, "Isuzu 110 - soon with an auto"? What slushbox have you decided to go with?

I'll give you a call soon. 😊

**PhilipA** · 29th March 2020, 07:49 AM

Will have to look up the current best practice for sealing the injector loom plug too

The later under rocker cover looms seem to be sealed well at the plug.
I worked on my old loom and filled the plug with 5 minute epoxy, which specs show stable to over 100C.

Mine is now what 7 years old and no leaks to ECU.

So Haven't needed to refit old loom.

Regards PhilipA

**Leo109** · 29th March 2020, 05:03 PM

Hi Guys,
Started checking the boost modulator wiring and tubing this arvo and found this:
Guessing that having half an air filter element sucked into the MAF meter duct wasn't doing much for engine performance. Hope I haven't dusted the engine too badly... The filter came in a green box, less than 15K km ago. Recommendations??

DIIA filter 2.jpg

DIIA filter 1.jpg

Thread: This is getting bloody annoying...

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This is getting bloody annoying...

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