Low range throttle

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jsbholden

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i had the disco in low range today. can anyone explain why the throttle is so sensitive compared to high range? slightest pressure on the throttle and the thing is off (engine rev wise and not speed!!!)
 
Coz the gearing multiplies the torque which is transferred to the wheels, which means the engine has to strain less to deliver its power to the ground, so there what the engine is doing is reflected much more accurtely on the ground and there is less cushion of what is effectively momentum.
 
I thought the same when I first tried low range but when you use it in the right context it feels right. On the way back from the off road course at Driffield, guess who didn't put it back in high range properly? I lost drive and was thinking it will cost many beer tokens to fix. A guy from Lancaster stopped in his ragtop series- thanks mate - and offered help just as I discovered what I had done (Or not!) On the way back from Driffield, I thoought that I had a burst hose but I have a holed radiator so that is this weekends job. Funnily enough, the guy from Lancaster stopped on his way past and offered a tow home. Good the Landrover community aint it. We were waiting for the Green Flag man so thanks and handshakes were exchanged.
 
its nice when someone stops to help, head the same a few weeks back when a convoy pulled over when they saw us with my bonnet up, didnt help much but was nice none the less.
 
jsbholden said:
i had the disco in low range today. can anyone explain why the throttle is so sensitive compared to high range? slightest pressure on the throttle and the thing is off (engine rev wise and not speed!!!)
Click to expand...

You may find that in low ratio, you need to use a higher gear to compensate.

For example, if high ratio first is not low enough because you want to go really slowly for some reason, then select low ratio and 3rd gear. It's not exactly the same but very similar. Then if you want to go slower still, select 2nd gear.

I find that unless I am going down a VERY steep hill, I never use 1st gear when in low ratio.

A better understanding of the available gears will help with the throttle sensitivity you are referring to.
 
thanks for the replies but its more to do with how sensitive the throttle is when in low gear. I thought the Disco's electronic throttle was supposed to change between high and low, being less sensitive in low range?
 
jsbholden said:
thanks for the replies but its more to do with how sensitive the throttle is when in low gear. I thought the Disco's electronic throttle was supposed to change between high and low, being less sensitive in low range?
Click to expand...


You've got me there jsb, I'd not heard of that before.

Dave
 
You could easily test this theory though, put your foot a fixed amount on the accelerator so you have say 2000 revs, in neutral, then move the transfer box from high to low and see if the revs changes. My money says it won't and that the increase in response is down to the increased torque in low range, but prove me wrong!!!
 
jsbholden said:
i had the disco in low range today. can anyone explain why the throttle is so sensitive compared to high range? slightest pressure on the throttle and the thing is off (engine rev wise and not speed!!!)
Click to expand...
Td5's were built with a switch on the hi/lo range,some early cars worked the wrong way round - they were meant to "dumb down" throttle response in low range to make the car easier to drive.The wrong way round made them flat in hi and jumpy in low.Stick it on Testbook and see which way yours is.(Then cut or join the wires to the switch and make it how you like it)
 
think that may be it. what is an early TD5? mine is a 2000. in high range the throttle is smooth but in low it is very jerky
 
they started Dec 98 so early enough to have that issue id say, my mates used to do the same-he never fixed it thoug b4 he sold it, let me know how you get on as mines a '98 so will probably encounter the same issue at some poiint no doubt!!
 
have pluged the disco in to a nanacom unit and that says its in low when the lever is in high. is it just a case of swaping some wires around so that the throttle is using the correct ECU map?
 
eightinavee said:
Td5's were built with a switch on the hi/lo range,some early cars worked the wrong way round - they were meant to "dumb down" throttle response in low range to make the car easier to drive.The wrong way round made them flat in hi and jumpy in low.Stick it on Testbook and see which way yours is.(Then cut or join the wires to the switch and make it how you like it)
Click to expand...

What he said maybe??
 
Missed this thread when it first came out.
You seem to have found your problem, so I hope you gwet it sorted.
As well as changing the peddle sensitivity, going into low range on a Td5 should remap the engine to produce peak torque at lower revs, as you generally need for off road driving.
This means that if your ECU has really been thinking it was in low when it was in high, you might find the difference more dramatic than you are expecting.
 
the idea from land rover on the TD5 was to de-sensitise the throttle in low range, theory being that in low range you are 'off road' and more likely to be going over bumps that may cause you to be stomping on and off the gas by accident. It's supposed to help increase your control on rough surfaces.
 
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