TD5 - and my massive headache.

When the surging mode works correctly - then the revs are smoothed during normal operations and the smoothing deactivated when the clutch is pushed down. As mine is reversed - the revs are not smoothed while normal driving and hereby feels the throttle too responsive. At least my theoretical conclusion so far...

Lars,

The clutch switch on the Defender Td5 is normally closed while the Puma engine has a normally open clutch switch. Have not seen a Puma one in real life but understand they look quite similar...

Are you able to read a part number on the switch? MSK50010 is normally closed while MSK500020 should be normally open. Having the wrong switch installed could certainly be the source of your troubles...

Another way of troubleshooting this issue would be unplugging the switch connector and setting up a makeshift interrupter between the ECU pin corresponding to C0658-35 (black ECU connector) and any earthing point.

Rgds
Matt

PS: currently reviewing your fueling data

Buckhandle said:

When the surging mode works correctly - then the revs are smoothed during normal operations and the smoothing deactivated when the clutch is pushed down. As mine is reversed - the revs are not smoothed while normal driving and hereby feels the throttle too responsive. At least my theoretical conclusion so far...

Click to expand...

Lars, this is the gist of it as RAVE states "Surge damping stops engine speed rising dramatically (engine flaring) during gear change"

which means if u bridge the two pins of the connector will be like the clutch switch doesnt cut the feed to ECM when u push the pedal... then because the engine was under load and u released the load of it by "clutching", the rev tends to rise for a short time... this switch is there to "tell" the engine management that there is no load and recalculate the fueling instantly cos otherwise there is a "inertia" untill the ECM based on other sensors input reduces the rev to normal limit. This is my theoretical conclusion .... we'll see which one is good.

I had an issue with my wifes nissan exactly in this area...the clutch switch was blocked and when the pedal was pushed the rev went up suddenly with about 1000rot then dropped easyly to normal in about 10 secs. replaced the switch and everything came back to normal.... that's why i said i dont see how it affects the throttle response...though the ECM might missbehave cos it's missing the feed from the switch while running .... let's hope u are right and that will cure your problem

Dear Matt and Sierrafery,

I have replaced the sensor with old one (normally closed circuit).

My thoughts were; if the ECU is 'informed' by the open circuit to cut the fuel or just reduce revs then this would be in conflict - as the clutch pedal was actually in rest position. If so ... maybe it would give a stuttery feel.

Anyway ...The car does not feel a lot better yet a little smoother. But it did not solve the problem ) The only thing that helps somewhat is really to bypass/loop the low-range signal to reduce the throttle sensitivity (discussed earlier). But this is not solving the problem .. just reducing symptoms.

Sometimes it all feels like gentle misfire. But when looking at Nanocom injector balance .. there is no sign of such misfire.

Matt - I have some new Nanocom data of today (post the refit of the clutch switch). I will submit shortly!

Lars

You said that the ECU was replaced with a newer version then u modified it for the 2 channel TP sensor... this sounds strange for me now and i dont see how is it possible(are u certain that they actually replaced the ECU not just reconfigured it to the original map???)... IMO put a new type of TP sensor to fit the new ECU. The 3'rd channel has the role to equilibrate the throttle response.

Check the throttle signal with nanocom on live data... albeit it will be strange cos the new kind of ECU will show a missing signal on diagnostics i think. IMO your problem is in this area, throttle and engine management cooperation.

Hi Sierrafery,

Sorry for my late reply!

The two-position sensor does not work with the ECU unless programmed to do so. It's standard practice and not an issue. I was there when the ECU was setup for this and when programmed for a three-position sensor there was no engine response at all. This part is all ok ;o)

The Nanocom signal for both sensors looks nice and perfectly mirrored .. so truly believe this part is ok.

But I agree … I also believe it is some kind of throttle issue ..

Lars

hi i have had this several times before!!

Majority of the time its a duff engine remap ( has a glich), has also been a faulty fuel pressure regulator, faulty injectors ( worn nozzle giving poor spray patterns) and very rarely but on a couple of occasions the inline filter inside the fuel filter housing was blocking up!!. if you look at the housing its located inside the left hand front union unscrew it and clean..

one thing can you clear up for me tho as a little confused atm... your runnin a later flash type ecu..yes? but this throttle tps is confusing me .... are u using a 2 track or 3 track tps and had this been configured correctly into the ecu?

also are the heaters warm?? and does the car use water?? as yours is a 2000 plate it would more than likly still have plastic cylinder head dowels wich allow the head to move slightly.........

cheers arron

Dear helpful LRO's !

I think I have found the weak link! Good news I believe but in general I also feel a little down. Down due to wasted money, time and effort. This is stupid - really.

I talked to a very experienced Mercedes mechanic and she! said: Often when having a diesel-mercedes running a little rough they turn their attention to the exhaust system. Leaks, cracks, dirty systems etc may cause a little rough running ...

So, immediately I thought of the mid-muffler which has been replaced by a straight pipe.
I refitted the muffler .. and there you go. It immediately changed the throttle sensitivity and the kangarooing was reduced dramatically. On top of this I can feel that the engine is running smoother - maybe also due to some of the other things solved. But anyway - it is not until now I feel the real effect of all 'improvements'.

However, there is no doubt - refitting the muffler made a BIG difference.

At this point I feel like the problem is solved....

For all of you guys - thank you for great support!!!

Lars

StoneyTD5: Thanks for your input! The ECU is a flash-type as it has been replaced. No water spill, not running warm (as long as I keep the radiator clean). The throttle sensor is a 2-track and the ECU has been configured accordingly.

Dear Lars,
I am having recently the same issues with my Defender TD5 (1999):
1. Revs continue to climb up for 2 seconds when i shift gears, especially from 2nd to 3rd
2. The throttle is extremely sensitive at low RPM (1000-1500)
3. The kangarooing effect is driving me crazy! and most sensed at 1st, 2nd and 3rd gear
4. When in low gear these all issues are increased dramatically
5. The engine smokes a bit more than usual since it all started
6. Cleaned all sensors (MAF, MAP, AAP) except CKP

After reading your excellent investigation, i thought i might focus on the clutch switch sensor.

I do admit it's kind of hard to imagine why these issues are encountered when the muffler is refitted....mine is still on, but i am thinking of disconnecting it for the sake of testing/eliminating causes.

Your thoughts and insights are most appreciated!
thanks,
Avner

Dear Avner,

First of all i would recommend you to read this ..
http://www.landyzone.co.uk/lz/f50/release-your-td5-power-199872.html

Rgds, lars

I'm having the exact same problem after having a new cylinder head fitted and then having to replace the ECU, but still my temp gauge reads backwards...

I've tried the following:
Re map (west coast remaps)
Disconnecting the throttle switch,
new MAF sensor
Cleaned the MAP sensor
New Harness
New Copper washers and o rings on injectors.

Makes ,me want to sell it. Drove perfectly before it overheated and cooked the head.
Thanks guys

Did you resolve this problem as i'm having the same problems?
Regards
Wayne