Is this normal?

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Michalis Karatzis

Michalis Karatzis

Active Member
Posts
189
Location
Cyprus
Well, I am not sure if my car has an issue but what I will describe doesn't seem normal to me. So I would like to hear your opinion on this :)

My car is a 2001 td5 auto with 120.000 miles, the EGR deleted, cat removed with straight through pipe, no remap (as far I know). It also has a Van Aaken Smartbox (more on this below). The gearbox is new from Ashcroft (the issue I will describe was there with previous box as well). Tires are A/T 245/70/16. No lift.

So, the issue is that when driving on the motorway using cruise control at 60-70mph (approximately 2200rpm) and find an incline (eg 1-2 miles long, at 4-5%) the car will sometimes kick-down from locked 4th to 3rd and rev hard for few seconds then go back to 4th and then lock. Sometimes it will do this twice on the same hill. In all cases the car was unladen (2 persons and nothing else) and not towing.
I don't find this normal, I would expect an engine like the td5 to be able to pull the weight of the car at this rpm and speed without issues. What do you think?

I checked a few parameters with a nanocom and MAF gives 50-600 consistently, MAP goes up to 215kpa (is this low?), temps are all ok, wastegate modulator is by-passed. The car accelerates and shifts fine (I dare to day it's fast) and I don't have any other complaints. No faults on Nanocom.

On another note, I removed the Van Aaken box and did some tests and could not tell any difference. I am not sure if it is supposed to give big increase in power or a marginal gain. When connected and the engine is running the lights inside the box are not lit, maybe is not connected right?
 
Normal, remember the D2 auto gear box is electronically controlled, so if the various parameters change the box changes accordingly.
Even my auto petrol engine D1 with its addition power the box will drop a ratio on some very steep hills but then thats at a lower speed around 30-50mph and never over 50, unless it’s “pedal to the metal” on hills to overtake :)
 
Michalis Karatzis said:
MAP goes up to 215kpa (is this low?), temps are all ok, wastegate modulator is by-passed.
Click to expand...
Yes, that MAP under full load is low, it should go to above 230, also the fact that the wastegate modulator is bypassed doesnt help cos that means the boost curve is too linear and wastegate modulation would make the boost to climb faster at lower revs so with modulator the boost would be higher than it is without it under a specific load ... it's also possible that the tuning box you fitted mixed up the whole addaptive strategy cos the transmission ECU was mapped from factory to work with certain torque/boost values at certain speeds and that data is delivered from the engine ECU via CAN while the tuning box is an external device which tricks the ECU and the sensor readings are not showing the reality.... sell it if you can and get a remap.... untill then as that tuning box was once fitted and you have nanocom go into the transmission ECU and reset addaptive values also reactivate the wastegate modulator ASAP,

btw when was the oil and filter in the box changed last time?
 
sierrafery said:
Yes, that MAP under full load is low, it should go to above 230, also the fact that the wastegate modulator is bypassed doesnt help cos that means the boost curve is too linear and wastegate modulation would make the boost to climb faster at lower revs so with modulator the boost would be higher than it is without it under a specific load
Click to expand...

I read on many places that the modulator is the source of many problems and by-passing it is not an issue. You say that with modulator the curve is more regressive? And if I reconnect it there will be more torque/power at lower rpm? Hence the box will not kick-down?

sierrafery said:
... it's also possible that the tuning box you fitted mixed up the whole addaptive strategy cos the transmission ECU was mapped from factory to work with certain torque/boost values at certain speeds and that data is delivered from the engine ECU via CAN while the tuning box is an external device which tricks the ECU and the sensor readings are not showing the reality.... sell it if you can and get a remap.... untill then as that tuning box was once fitted and you have nanocom go into the transmission ECU and reset addaptive values also reactivate the wastegate modulator ASAP,
Click to expand...

Reset the adaptive values after I remove the tuning box or should I keep it? I'm not even sure if the tuning box does anything to be honest. And the nanocom I have is the old metalic one, can I do the reset?

sierrafery said:
btw when was the oil and filter in the box changed last time?
Click to expand...

Box has 2000 miles after I received it from Ashcroft so consider it new

I am also thinking that maybe this is a quirk on the way the CC operates and not an issue with the engine/gearbox
 
Michalis Karatzis said:
I read on many places that the modulator is the source of many problems and by-passing it is not an issue.
Click to expand...
Bypassing it brings the D2 to the setup of a defender which has different fuel map and there are no automatic defenders, that modulator is important for the D2 to work as it was conceived, bypassing it is valid for diagnostic reason to rule it out in case of overboost not to downgrade the D2 by completely letting it inactive.... it improves the throttle response at lower revs as it keeps the wastegate closed untill the boost builds up enough to gain proper power also the ECU expects a certain boost at a certain rpm based on wastegate control which in this case is missing so the management is mixed up .
Michalis Karatzis said:
Reset the adaptive values after I remove the tuning box or should I keep it?
Click to expand...
get rid of it then reset the addaptive values, eventually wind up the wastegate a bit to let 10 threads on the rod
Michalis Karatzis said:
I am also thinking that maybe this is a quirk on the way the CC operates and not an issue with the engine/gearbox
Click to expand...
i dont know exactly how it's in real life as i have a manual but IMO what you described doesnt seem too good to me

btw did you check the ECU red plug for oil?
 
Last edited:
Michalis Karatzis said:
I am also thinking that maybe this is a quirk on the way the CC operates and not an issue with the engine/gearbox
Click to expand...
It is a combination of the vehicle weight, a four speed gearbox and the lack of power from the Td5 engine.
So in their wisdom LR with their knowledge from the lack lustre Tdi auto added electronics to the four speed box to improve performance and economy, a box that was matched to a petrol engine RR back in the 1990s.

So your issue is that the box drops a ratio to relieve the engine from labouring on a hill, I’ve seen many D2s slow on motorway hills, they approach at a steady speed and at the top regain their speed again, even with a manual box with Cruise Control active a ”press on driver” would possibly be thinking of changing down from fifth to fourth to keep up momentum... non of that with a petrol engine disco.

So all you have to do is increase your speed, have you tried to increase your speed with the CC automatically doing it, just press and hold the SET button to increase your speed on the hill, and then release when the box changes up to top, or of course just press the accelerator pedal down further. :)
 
discool said:
So in their wisdom LR with their knowledge from the lack lustre Tdi auto added electronics to the four speed box to improve performance and economy, a box that was matched to a petrol engine RR back in the 1990s.
Click to expand...
LR has nothing to do with adding electronics cos that was made by ZF for other vehicles too and you can't compare a mechanical early ZF with the electronic one IMO ... the OPs problem is about mixed up powertrain electronic management, unless what he described it's a normal behaviour which i doubt
 
Your lost in your translation. Or perhaps I should have said: So in their wisdom LR with their knowledge from the lack lustre Tdi auto, asked ZF to supply an electronic controlled gear box gear box to their specification that was specifically for the D2 Td5 electronic systems they would be adding when in production.

But then...I think most if not all would know that ZF supply the gearboxes to a specification as requested by the vehicle manufacturers and the electronic systems they intended to use in their vehicle.
 
discool said:
Your lost in your translation. Or perhaps I should have said: So in their wisdom LR with their knowledge from the lack lustre Tdi auto, asked ZF to supply an electronic controlled gear box gear box to their specification that was specifically for the D2 Td5 electronic systems they would be adding when in production.

But then...I think most if not all would know that ZF supply the gearboxes to a specification as requested by the vehicle manufacturers and the electronic systems they intended to use in their vehicle.
Click to expand...
Now that's the best explanation i've ever seen, i could have said that so well only in my first language :cool: .... which means that ZF supplied a box to suit the Lucas Td5 management(which was also requested by LR) and the ECUs work together well as they were mapped based on LR's specifications so any "intrusion'' into this algorythm(like a tuning box for example or even a bad remap) would mix it up and the vehicle might not behave as it should... something like that was what i meant in my third language :)
 
Thank you all for the replies.

So I removed the Smartbox (I can't tell any difference anyway), I will order a new modulator (PIERBURG) to replace the by-passed one since I am guessing it's a faulty one, I am also considering replacing the wastegate actuator just in case with this https://tinyurl.com/ybcblwtn and then check my MAP so it goes up to 230kpa (or more).

After that I will report back with the results.
 
seems that you have a good plan...go for it
icon_thumbup.gif
 
Yes, i have MBC + forge wastegate actuator + uprated billlet turbo cartrige + performance intercooler + alive stage 1 remap + big alluminium radiator + ECT and EGT gauges + many other tunings :cool:
 
UPDATE

So I removed the Smartbox, fitted a new modulator (PIERBURG), fitted a new original MAF, fitted new original injector loom and everything looks to work fine now. The only thing I'm not 100% sure is if I'm getting the maximum from my td5. I did see instantaneously 228 kpa a few times but under full load is more close to 220kpa (these are readings on a mk1 Nanocom). The actuator looks tampered with and the thread is a bit damaged so it doesn't really wanna move.
I'm also considering trying out an MBC to see if it improves things a bit....
 
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