washing your car makes it go better!

[feraldisco]

I've had an issue with my 1999 D2 Td5 manual for a while now - doesn't run smoothly at constant speed in first, won't rev easily beyond about 2500rpm, doesn't have as much power as it's chipped 85kw on dyno would suggest (apparently TRS chips normally produce about 75kw in third gear/3000rpm on dyno, and was told this was the highest output they'd seen). No particular faults have shown up, harness and turbo boost modulator have been replaced and MAF gets cleaned and I think it's ok.

Anyway, gave the underneath of the front end a good steam clean the other day to get rid of some oil weep grime, and she runs much better now! Still not keen to rev much beyond 2500rpm, but smoother and more power to quite a significant degree (i.e. not my imagination).

Given that I only sprayed from the bottom up (i.e. not from top into engine bay), any ideas of what grimey/resistance-prone connection/sensor I might have renewed power to?

[slug_burner]

If you cannot get more than 2500 rpm before or after spraying you have got a problem. I'd be looking at the injector harness, maybe the throttle potentiometer. Does it appear to cut off as you get up to 2500 rpm? if so you might have a fuel starvation problem, in which case you should be looking at your filters and pump or an over boost problem. Cannot tell by your description.

[feraldisco]

definitely not injector harness - that's been replaced and made no difference. If I really put the foot down, it will get to 4000rpm without cutting out, but it certainly doesn't wind out freely beyond 2500rpm (and the fact that it runs rough when holding it at around 2000rpm in first may also be a clue). Apart from first gear it is super smooth to 2500rpm (the smoothest TD5 I've driven) and it gets good fuel economy (not being able to go over 2500rpm very well helps of course!). I had a generalist diesel mechanic check fuel supply, turbo boost, air leaks etc and all that was fine. Graeme Coopers were too busy to give it a thorough going over (I live in Canberra, so can't leave car with them for more than a day and don't trust any of the Canberra so-called LR specialists) - they cleared the fault codes and that was about it. I could start replacing sensors, but that's an expensive way to go without a firm diagnosis...

I had the problem before and after fitting TRS ECU, so that's not it either - still a barrier at 2500rpm, but I've now got more power on the way to 2500rpm!

[Blknight.aus]

pull your hoses and check them for delamination.

my opening thoughts would be the boost modulator unit on the turbo.

[feraldisco]

yep, after researching this site, I thought turbo boost modulator as well. I realise I probably could have tested this by bypassing it, but for the sake of $50 I just bought a new one...unfortunately made no difference! And unfortunately the hoses are fine too.

A friend sussed it out with his new Nanocom, and while he might not have been across all the Nanocom functionality at the time, couldn't find anything obvious. A truly bizarre and frustrating problem as I suspect it will go like the powers of p*ss if I can get it to rev out to 4000rpm freely, given that Graeme Coopers were surprised by the high power output on the dyno.

[Panya]

Guessing here but I would clean and tighten all the earth points at the front of the car. Maybe you made a better earth with the steam cleaning and the problem is that the ECU or some other electronic control gizmo is not properly earthed so you are getting the poor running? 1999 would give 10 years for loose connections/corrosion to stuff up a fair number of earth connections and it is the only thing I can thing of that would possibly be affected by your front-end steam clean...

[JDNSW]

Guessing here but I would clean and tighten all the earth points at the front of the car. Maybe you made a better earth with the steam cleaning and the problem is that the ECU or some other electronic control gizmo is not properly earthed so you are getting the poor running? 1999 would give 10 years for loose connections/corrosion to stuff up a fair number of earth connections and it is the only thing I can thing of that would possibly be affected by your front-end steam clean...

Good suggestion - I would run a new chassis/engine earth link and see if that improves matters, but check all other earths you can find, wherever anything to do with the engine is earthed.

John

[bronson]

Hi feraldisco

I also have a td5 of the same yr, I noticed the exact same scenario with mine some time back. I have done the Inj loom as this was a big problem, and I think that it has gotten rid of this issue, but I wolud be really keen to find out what it was at the time so I could check mine as well.

cheers bronson

[Jordos D2]

hy guys how high should it rev ?? my 2001 td5 man only gets to 3000rpm and then feels like it becomes a little doughy not that i very keen on reving it past 3000rpm anyhow its all standard to i will add

[350RRC]

Washing mine does the same. My POS is red and red is a very fast colour. :) The more of it that is visible the faster it goes.

cheers, DL

[Landy Leon]

I saw an episode on mythbusters and they proved that clean clean cars get longer fuel milage

[big guy]

I did see that too.
It was not on a 4by4 though and minimal.
They do polish airliners though for less friction and it does make a difference.

Got to love mythbusters.

[feraldisco]

actually I know think that the problem may lie with the throttle pedal assembly or associated wiring to ECU... did a more comprehensive search of AULRO and other sites last night after a frustrating drive through the alps where being restricted to under 2500rpm was a pain... It appears that quite a few early model manual D2s have the problem of not being able to rev cleanly beyond 2500rpm and some of the posts mentioned that the throttle position sensor/assembly/wiring was the problem. I then remembered how the car seems to accelerate better under cruise control 'resume' than through using the pedal...so hopefully this is my problem and should get a chance to check it out tomorrow. Incidentally, when they do dyno runs on vehicles with electronic throttles, do they bother using the pedal or would they just use cruise or somehow control revs through the ECU? I ask because she got a very good dyno reading and the people doing the dyno didn't think there was any problem with it revving out.

Incidentally, the other interesting thing I discovered about improving manual D2s was the disconnection of the plug attached to the clutch master cylinder to improve gear change smoothness. Never heard mention of this before despite years on the forum - I guess that just reflects the fact that the manuals are relatively rare...

[feraldisco]

actually on further searching it seems that the clutch master cylinder plug disconnect only relates to Defenders...

[Tombie]

actually on further searching it seems that the clutch master cylinder plug disconnect only relates to Defenders...

And wont work with Cruise...


A word to all, be careful what you read on a forum...
Dont go pulling plugs etc without care and consideration.

I'd suggest Throttle assy, or Fuel Rail Pressure (Pressure Reg)

[feraldisco]

And wont work with Cruise...


A word to all, be careful what you read on a forum...
Dont go pulling plugs etc without care and consideration.

I'd suggest Throttle assy, or Fuel Rail Pressure (Pressure Reg)


true - always handy to know the potential negatives as well as positives of any modification...you would, after all,think that most things fitted in the factory have a useful purpose, but in some cases the negatives outweigh the positives as per EGR.

I realise that not having a functional clutch switch will mean that gears shouldn't be changed when using cruise control - My D1 had aftermarket cruise without a clutch switch so I'm used to this, and presumably you could set up a switch near the cruise control controls to allow you to switch the clutch switch off and on as required.

[bronson]

I definately know that mine hates gear changes when there is oil at the ecu, just wondering how long before the residual works it way out though, the ecu plug has been cleaned about four times now!:thumbsdown:

cheers bronson

[bronson]

And wont work with Cruise...


A word to all, be careful what you read on a forum...
Dont go pulling plugs etc without care and consideration.

I'd suggest Throttle assy, or Fuel Rail Pressure (Pressure Reg)
Whats the best way to test this Tombie?

[bronson]

Hi all
just wondering if anyone knows roughly how long it takes all the residual oil to come through to the red ecu plug?
I reckon Ive cleaned the ecu plug 6 times and it still seems to come through very lightly and plays havock with the ecu.
I also have modified the injector harness to fix this problem!Q

cheers
bronson

[bronson]

And wont work with Cruise...


A word to all, be careful what you read on a forum...
Dont go pulling plugs etc without care and consideration.

I'd suggest Throttle assy, or Fuel Rail Pressure (Pressure Reg)

Hey tombie,
how would you go about testing this on a td5 disco?

cheers bronson

[ADMIRAL]

I saw an episode on mythbusters and they proved that clean clean cars get longer fuel milage

Yes but so does putting 80psi in the tyres......doesn't mean you have to like it !