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TD5 hi/Low


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its been on here before but i cant find it

i dont want the td5 to sense when its in low and hence adjust the throttle mapping. i would like the same throttle response in Low as High

so if i disconnect the plug does it achieve this or does it need default to low with it disconnected?

ie do i need to join the two wires if i disconnect it.

I know i could go out and try it, buts its dark!!

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its been on here before but i cant find it

i dont want the td5 to sense when its in low and hence adjust the throttle mapping. i would like the same throttle response in Low as High

so if i disconnect the plug does it achieve this or does it need default to low with it disconnected?

ie do i need to join the two wires if i disconnect it.

I know i could go out and try it, buts its dark!!

Depends on the vehicle....

Most you need to bridge the two pins on the harness side of the plug, so that it stays in 'high' all the time.

Unless you have diagnostic kit, just unplug it and go for a drive in high - if very unresponsive then you need to bridge the pins.

Ian

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I have noticed that about half of the TD5s we check on the computer report the wrong ratio and often it doesn't change when the lever is operated. Whatever it does, it doesn't seem to make much difference.

Silvio knows all about this mapping, so maybe he will answer this thread. Apparently some ECUs work backwards to stop the engine stalling?

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Thanks, Jim, but I'm no real expert!

Other guys made extensive tests to understand how this stuff works, and the results are not at all plain.

It seems there are interrelations among the Hi/Low switch and other parameters in the Td5 management: it seems that in Low position the ecu will not manage the EGR (no emissions tests in low range??!), and will not consider the inputs from the clutch switch as well.

Combining both things might change, on some vehicles, the overall behaviour of the engine.

As Porny says, on most vehicles the Hi/Low switch is in the open position when il Low range; in this position, without egr and clutch switch operation, the engine might perform slightly better, though you'll have a gas pedal with a longer travel.

If you wish to understand if your Hi/Low switch works as it should, make this test (better if performed with the help of a friend):

a) bring the engine to a higher than idle number of rpm

B) move the transfer lever from high to low: you should hear the engine slowing down noticeably, with the gas pedal remaining exactlyu in the same position (for this it is important to have a friend: one will keep the pedal steady, the other will move the lever).

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thanks guys.

it looks like i need to go out and disconnect it and see how she drives - ie the high or low throttle setting.

i know it definitely works - cheers for the confirmation.

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