Thread: Drive by wire throtlle tuning?

Hi Mick
When you sort it you can sort mine!!!!! Mine is EXACTLY the same down low.like bad turbo lag.Silicone hoses have helped but not cured the problem.
No signs to say if the ECU is chiped.The problem isnt there in low range is yours,even taking off in 2nd or 3rd.
Andrew

(Sigh)

This is a constant complaint with these engines. I have my own theory on this, and it hinges on the fact that the cubic capacity and stroke length of these motors doesn't add up to low down torque. To get any sort of low end response from a small capacity/ dimensionally challenged engine, you have to have gas flow, along with sensible fuelling( Not allowing excessive EGT's or smoke etc) at the critical point. I honestly believe that this is a limit to the Td5, and short of running 1.6:1 high range transfer gears and a GKN overdrive or putting up with excess smoke, EGT's and fuel consumption, there is little else that can be done. I also think that the best friend of the modified Td5 is the auto trans, allowing a buildup of torque through torque converter slippage creates a 'wave' of gas flow that basically overcomes the lag issue to a point. There is nothing that can be done to make these engines pull like a big capacity long stroke diesel, I have a client with a naturally aspirated Isuzu 4BD1 county that will pull away from the lights with a boat on the back easier than his chipped Td5 'fender, and he is flabergasted at the BOTTOM END torque of the 110. Of course the 'fender will eat it alive above 40kmhr, but the point is the yawing abyss between the 4BD1 and the Td5 is quite evident in this example. Don't forget, the same person owns both vehicles, and he tows the same boat with them up the same hills....I have no problem with the chip upgrades on the Td5, it makes them a far better drive than standard, for no extra fuel and gives a safe overtaking margin. I'm just pointing out that most people are expecting too much from an engine that is the same cubic capacity but with LESS stroke than the 300Tdi, and is absolutely nowhere close to the 4BD1 for low down torque,( 1000 to 1800 rpm) especially a turboed one.
Sorry to throw a pussycat in amongst the rats with wings here....But it had to be pointed out.

JC

Originally Posted by LandyAndy

The problem isnt there in low range is yours,even taking off in 2nd or 3rd.
Andrew

Generally and most recently no, but it has on occasion dropped out in the past when I would have expected it to pull fine. Up hill for example, with 4.11s fitted and running 32"tyres, it has stalled a few times on me when it really should have kept pulling without hesitation. I think that as it has been with me for so long now I have adapted my off road (and on road) driving to accomodate the drop out down low but even thids sometimes will not do the job. Sometimes it just feels dead and as if the engine is not breathing properly or is being held back somehow.

Another test i did whilst having a shot of a mate who has the same year manual TD5 was to blip the accelerator to full tavel as fast as I can and my rev needle barely registered where as his moved up far more than mine. Another test was to feather the accelerator up and down to try and keep the revs up or at least catch the revs as they fall each time.........mine seems to just ignore some presses of the throttle and will not maintain smooth rev blips and just falls off to near nothing if you don't get the frequency of presses right as opposed to when you ACTUALLY press the throttle (if all that makes sense) It really feels as though the throttle has been mucked around with and is no longer acting or responding to my input when i want it. Even though it is drive by wire it should still act as though there is actually a cable is connected.

Did you say you were unsure if yours was chipped?

I took my 130 in to be chipped with the BD chip about a year ago, I'd already paid, sitting in the office of AMV, waiting as the mechanic test drove it with the new chip. He came back and said there was a problem with the throttle potentiottomer (spelling?) and it needed to be fixed at extra cost. I said is was fine, I'd had no probs, they put it on test book and it came up a problem with the Tp (abbrev.) They said it needs replacing. I said, could you put back my original ECU and see if the problem is still there. It wasn't, my original ECU was fine, as was the TP. They said they'd have to send the faulty ECU back to BD. Gave my money back, But I never got around to getting that chip upgrade...

Ben 00 cc130 td5, sadly going tomorrow (soon to be 99 disco td5)

the throttle pedal is a simple variable resistor........

if you unplug it and put an ohms meter across it....and check the resistance through its entire travel.........

as you slowly press the pedal.....the resistance should change accordingly......nice and smoothly.......
if there is any jumping or bouncing of resistance it may indicate a worn pedal rheostat........

maybe......you could borrow one off another vehicle to test out.....

I have installed a switch to simulate low range. This gives a much more gradual throttle and I find it works well with the chip. The hesitation is still there, but at much greater pedal movement, so its not the TPS. I have a throttle opening after which a little more throttle and the engine hesitates quite badly. It occurs on the freeway too - have to press the throttle past that spot. This dead spot is the same spot that causes loss of power when taking off - power is OK with just a little throttle then nothing. If the throttle is pressed with the vehicle out of gear then engine runs poorly at a particular position. Its as though there's a serious mis-match of fueling at those revs/throttle, but I suppose it could even be the turbo not spinning-up as it should. Something's amiss but I haven't found it yet.

The MAP (manifold absolute pressure) sensor is used along with other sensors in the calculation of the mass of air getting to the cylinders and is crucial to fueling calculations. It is also used to detect when the boost limit has been reached so that the wastegate can be opened to prevent excessive boost. Its mounted on the inlet manifold and is combined with a temperature sensor (IAT inlet air temperature).

Can you guys who are having this trouble try an expiriment,dont blame me if the cops book you.
Find a big hill that the best you can do up is 100ks holding her flat in 5th.Drive the hill get the feel for it.
Now try again,but get the cruise set up for 120/125ks in 5th.Hit the bottom of the hill as per normal at your 100/110 with the cruise off,hold it flat and see your normal just hold the same speed.Now hit resume,tell me there is a huge improvement,that ecu can do something your right shoe cant.If its only me I need the throttle potentiometer looking at.My acceleration under cruise is nothing the pedal can match.
Andrew

Originally Posted by LandyAndy

Can you guys who are having this trouble try an expiriment,dont blame me if the cops book you.
Find a big hill that the best you can do up is 100ks holding her flat in 5th.Drive the hill get the feel for it.
Now try again,but get the cruise set up for 120/125ks in 5th.Hit the bottom of the hill as per normal at your 100/110 with the cruise off,hold it flat and see your normal just hold the same speed.Now hit resume,tell me there is a huge improvement,that ecu can do something your right shoe cant.If its only me I need the throttle potentiometer looking at.My acceleration under cruise is nothing the pedal can match.
Andrew

Very interesting indeed, might give it a try this weekend if I can find a suitable hill......would certainly add some info to the debate and diognosis.