Excessive throttle pedal travel

[MickG]

Okay, solved my speedo problem so now onto the next niggle.

SET UP / HISTORY: '99 Manual TD5 Disco 2, re-mapped Bruce Davis ECU, 4.11 diff gears, 32" muds, True Speed speedo correction unit, new EGR valve fitted. Has been used for towing a caravan.

PROBLEM 1: I have about 1-2" travel in throttle pedal before revs start moving, which means sometimes it can be hard to get the biting point right. Can the pedal be adjusted so that it responds straight away even though it is drive by wire, i.e. as soon as the pedal in depressed and not 2" later?

PROBLEM 2: Perhaps because of the excess throttle travel but I'm sure because of something else also, the throttle reponse and torque is pretty (very) lame off the mark and I sometimes stall the car :oops: . Particularly bad when trying to pull away going up hill. It seems the torque is just not there to pull the car away smoothly and if I don't get the biting point right, it can just drop out completely with revs dropping way back, even though my foot is pretty far down on the throttle and this makes for a very jumpy take off. Everything seems to be okay when moving although I would really like some more low end torque as even with the re-mapped ECU, it is not crash hot.

The ECU was re-mapped again recently and everything was on fire for a week - great take off, nice power delivery and good low down torque but alas, things have dropped back to ordinary again for some reason.

Hopefully I have explained myself well enough above, but a suggestion I had from a previous post was to remove a connector under the bonnet - haven't tried that yet but may depending on info received back this time.

Any help / advice appreciated again. Apologies to those who are fed up of hearing about my constant niggles.

Aye, Mick

[DEFENDERZOOK]

<span style="color:blue">the throttle pedal is a variable resistor....and there should be some kind of adjustment somewhere (not sure as i havent looked)
find the wires and test it with an ohms meter.....
start to press the pedal slowly and watch the reading on the meter....
it should either increase or decrease resistance as you press it....
the change should start straight away and be smooth without any jumps/fluctuations in the reading.....

if this checks out ok your problem may not be in the pedal.....

does the TD5 have a stepper motor to control throttle openings or just the injectors....? (i dont know)

check also that there is no oil in your wiring connector to the ecu......
and that is is fitted securely....unplug it and then plug it in again....</span>

[George130]

I was led to beleive the TD5 have a smart accelerator. Push it a small amount and it responds realy push it and it waits a bit incase you had hit a bump and didn't mean it to respond. Supposed to make off road easier.

[siegucci]

There is no adjustment for the pedal.
Check your high/low range switch on the transfer box. What you describe sounds exactly like a vehicle driven in low range. The ECM has a different mapping for low range to give you that extra travel to smoothen it and prevent jerking when going over rocks and stuff.
You can actually see the switch status on TestBook real time monitor. That might make it easier for you to check the switch.
Hope this helps.

[MickG]

Originally posted by siegucci+--><div class='quotetop'>QUOTE(siegucci)</div><div class='quotemain'>There is no adjustment for the pedal.
Check your high/low range switch on the transfer box. What you describe sounds exactly like a vehicle driven in low range. The ECM has a different mapping for low range to give you that extra travel to smoothen it and prevent jerking when going over rocks and stuff.
You can actually see the switch status on TestBook real time monitor. That might make it easier for you to check the switch.
Hope this helps.[/b]

Cheers siegucci, will check this out with my mechanic and see what happens.

<!--QuoteBegin-DEFENDERZOOK
the throttle pedal is a variable resistor....and there should be some kind of adjustment somewhere (not sure as i havent looked)
find the wires and test it with an ohms meter.....
start to press the pedal slowly and watch the reading on the meter....
it should either increase or decrease resistance as you press it....
the change should start straight away and be smooth without any jumps/fluctuations in the reading.....

if this checks out ok your problem may not be in the pedal.....

does the TD5 have a stepper motor to control throttle openings or just the injectors....? (i dont know)

check also that there is no oil in your wiring connector to the ecu......
and that is is fitted securely....unplug it and then plug it in again.....[/quote]

Cheers DEFENDERZOOK, not sure of the questions you ask but will check this with my mechanic soon. Cheers for the input.

To give a bit more info, it is really jerky when coming off the pedal and changing gear, especially when pushing the car. Drives like a small car just now. I take my foot off the accelerator to change gear and the engine kicks back with a small jolt and doesn't seem to rev out nicely like it did before allowing for a smooth gear change, does it both changing up and down gears. Also noticed the power from the re-mapped ECU is not really as strong as it could be. I'm guessing it must have something to do with incorrect signals being sent through the system as I have changed gearing, tyres etc - even though the speed reads right and the cruise works fine. Really starting to get to me now as it requires so much concentration just to drive smoothly and even then it is very rough compared to how it used to drive.

Hopefully someone will hit the nail on the head for me but I will be passing all info anto my mechanic as I know very little about the inner workings of a TD5.....or any engine for that matter.

Cheers again, Mick

[DEFENDERZOOK]

<span style="color:blue">go to low range and back to high a few times to see if you have a switch sticking as described above.....

it is supposed to de-sensitise the accelerator in low range......</span>

[LandyAndy]

Hi Mick
I have the same with my Disco,exactly as you have described,but have learned to use it.They dont like lugging,pull out from an intersection in 2nd or 3rd whilst moving floor it and it stalls or just sits there feeling sorry for itself,but in 1st and a bootfull it loves it.My truck at work has a "fly by wire" throttle as well,and it shows very similar traits to the Disco,the other similar truck which is a tad older has a normal throttle is totally different to drive.
Others have mentioned "clutch wires" etc,I think it may be a matter of adapting to the electronics,they are definateley a different beast to drive than the norm.I think that as you are picking up on these points you are probably more intune with your vehicle than "joe average"
Andrew

[MickG]

<span style="color:blue">go to low range and back to high a few times to see if you have a switch sticking as described above.....

it is supposed to de-sensitise the accelerator in low range......</span>

Tried this and at the risk of jumping the gun, this seems to have solved the sudden drop out when taking off, so than ks for the tip.

[quote=LandyAndy]Hi Mick
I have the same with my Disco,exactly as you have described,but have learned to use it.They dont like lugging,pull out from an intersection in 2nd or 3rd whilst moving floor it and it stalls or just sits there feeling sorry for itself,but in 1st and a bootfull it loves it.My truck at work has a "fly by wire" throttle as well,and it shows very similar traits to the Disco,the other similar truck which is a tad older has a normal throttle is totally different to drive.
Others have mentioned "clutch wires" etc,I think it may be a matter of adapting to the electronics,they are definateley a different beast to drive than the norm.I think that as you are picking up on these points you are probably more intune with your vehicle than "joe average"

Thanks LandyAndy, but I have been driving this beast for over a year now and have had the thing purring nicely. Admittedly, it has been on and off the whole time I have had it but I would so love to get it to drive like I know it can....all the time!!! It was performing best when Bruce Davis had a 2nd look at the ECU and found some solder defects, but then a week later it was back to being sluggish and not at it's best. Surely it can't be too much to get it to drive nice for an extended period of time? Assuming the jumpy start has been solved by moving the CDL switch, the lack of low down torque and power must be something to do with incorrect signals being sent due to new diff ratios, wheel diametres and a speedo correction unit?

Aye, Mick

[DEFENDERZOOK]

<span style="color:blue">i would also be getting that switch looked at....
who knows what else it tells the computer to do.....</span>

[Maggot4x4]

Think back to when you first had the problem, what was the mod you did just before that?

Try undoing that mod and see if it fixes it.

[MickG]

Originally posted by Maggot4x4
Think back to when you first had the problem, what was the mod you did just before that?

Try undoing that mod and see if it fixes it.

It all went pear shaped when I fitted the re-mapped ECU but this has been back for a 2nd look. Will see if I can get it out again and see how it goes.

Cheers

[MickG]

Quick update, turns out it might have been the throttle position sensor as this has been replaced and this seems to have solved the jumpyness off the lights and jerkyness when changing gears....power seems to be back as well. Still belching smoke at 1800 - 2200 rpm and could do with a bit more low down torque from 1000 - 2000 rpm but hey, i'm happy for now.

Cheers for all the input guys, until my next problem, aye, Mick

[MickG]

Okay, for those still interested, my jerky problems and power drop off remained for some time after throttle sensor was changed and a few other things lokked at. Last week it was plugged back into Auto Logic and a new fault appeared - Crank Angle Sensor - so, the connectors and plug have since been cleaned and would you beleive it the throttle appears to be doing what it should in high and low range:D :D :D :D :D

Hate to jump for joy too early as I've made that mistake before but for the last few days it really has made a significant difference firstly to me being able to take off from lights and also noi more kangarooing in low range and having to select a lower gear with more revs to tackle anything.

Anyway, lets hope this continues but for those who have a similar problem, clean out the connectors on the crank angle sensor.

Aye, Mick