WTF, mine has never been over 3000, I must be babying it:(Quote:
Originally Posted by SO69WA
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WTF, mine has never been over 3000, I must be babying it:(Quote:
Originally Posted by SO69WA
Hi - when you look up symptoms for throttle position faults, most of them seem to relate to idling problems. I'm curious to know if your vehicle also had idling issues. My Disco has exactly the same revving/power delivery problems as yours had, but no idle issues and no TPS faults registered on Nanocom. Before I fork out $170 for a new throttle/sensor assembly, plus pay someone to program it, I guess I'd like to get a bit more confirmation that this is actually the problem. Mind you, I've just about replaced all other likely contenders - loom, MAF and turbo boost modulator, so what's another one! One day I'll get the full benefit of the 85rwkw that the vehicle gets on the dyno...Quote:
Originally Posted by SO69WA
Innitially, the engine, when up to op temp was running rough and thats what got me into chasing my tail,
so systematically i went through all sensors to see how they made the engine perform when not active,
and what sensors made a significant contribution to the engine whether the engine was hot or cold, and if faults logged as expected,
intruth, i free reved it alot to duplicate the poor running/ vibraion not rolling, to discount drive train, thats when i discoverd the flat spot / revs fluctuating, interesting!!!, so when the driver demand fault logged i made a note, as i didnt do it,
originally i thought suss as you free rev the engine and held revs at say 2750, if you really slowly depress the throttle further, the revs would not rise, and in some cases drop 50, and then hunt 100 rpm, not normal!!!,
initially i was told it was the turbo cavitating- BS as turbo does not boost until loaded, fuel starvation- BS as free rev is light load, it had to be a computer issue, with really the sensor first asked being the issue?!!!
It always idled fine, apart from when i removed the coolant wire and then it rose but still smooth and civillised,
The Fault did not register all the time, but during the number of diagnosis sessions it was noted as the only sensor fault that would come up that i didnt create,
Oil in the loom complicated the search, and i now believe the vehicle would cool down during the oil wipe out proceedure giving the impression it was fixing it,
the engine definitely runs significantly better than before with the accelorator replaced, ie like youve just given the injectors a clean, sharper, more responsive,
it appears these may have a shelf life and do wear, differently maybe, but do wear regardless, engine now free revs as you would expect,
it still vibrates alittle more than i would like when really hot, but i think now it could be mounts as i can drive to Geralton and it runs fine, but as soon as stop start driving starts in town it deteriorates, & having clutch fan active and air con on speeds up the process, but do not directly contribute to the vibration,
as revs rise the vibration decreases as per engine harmomics, hence my thinking a hot engine mount not isolating the engine as much under max tourqe
GeneralAn engine control module (ECM) controls the five-cylinder direct injection diesel engine, and works on the drive by
wire principle. This means there is no throttle cable, the ECM controls the drivers needs via a signal from the Throttle
Position (TP) sensor on the throttle pedal.
The ECM is a full authoritative diesel specific microprocessor that also incorporates features for cruise control and air
conditioning control. In addition, the ECM supplies output control for the exhaust gas recirculation and turbocharger
boost pressure. The ECM has a self-diagnostic function, which is able to provide backup strategies for most sensor
failures.
The ECM processes information from the following input sources:lMass air flow sensor.REPLACED, improvement in topend performance
lAmbient air pressure sensor. CLEANED no Change
lManifold absolute pressure/inlet air temperature sensor.CLEANED No change, rougher when disconected
lEngine coolant temperature sensor.CHECKED, WORKING
lCrankshaft speed and position sensor.WAS MY next bet if throttle pos sensor ok
lThrottle position sensor. REPLACED, Good Improvement in Drivability
lFuel temperature sensor.Replaced no Change
lAir conditioning request.
lAir conditioning fan request.
lBrake pedal switch.
lClutch switch.
lCruise control master switch.
lCruise control SET+ switch.
lCruise control RES switch.
l High/low ratio switch.
ENGINE MANAGEMENT SYSTEM - TD518-1-18 DESCRIPTION AND OPERATIONThrottle Position (TP) sensor– Up to VIN 297136
The TP sensor is located on the throttle pedal assembly. It detects throttle pedal movement and position. It uses two
position sensors to provide the ECM with the exact throttle pedal position. As the pedal operates the voltage of one
position sensor increases as the other decreases.Input/OutputThe ECM provides the throttle position sensor with a 5 volt reference feed. Both position sensors send an analogue
signal back to the ECM.lSensor one, 0 to 5 volts variable.
lSensor two, 5 to 0 volts variable.
Input to the throttle pedal position sensor is via pin 14 of the ECM connector C0658. Output from sensor one is
measured via pin 12 of the ECM connector C0658. Output from sensor two is measured via pin 36 of the ECM
connector C0658. The earth path is via pin 26 of ECM connector C0658.
The TP sensor can fail the following ways or supply incorrect signal:
lSensor open circuit.
lShort circuit to vehicle supply.
lShort circuit to vehicle earth.
lWater ingress.
lSensor incorrectly fitted.
In the event of a TP sensor signal failure any of the following symptoms may be observed:
lEngine performance concern.
lDelayed throttle response.
lFailure of emission control.
If the TP sensor (COMPLETELY) fails, the engine will only run at idle and the MIL will remain on until the fault is eliminated. Turning
the ignition off/on can reset the MIL provided that the fault has been rectified.
Hey Gold TD5
You havent experienced the boost cut out on a chiped TD5!!!!!
MATE THERE IS MUCH BEYOND 3000!!!!
Andrew
OK, your reference to the cruise cut out, does seem to vindicate the TPS,
this cut out is it load dependant, like up a hill / air con/ towing, or does it do it hot and/or just after a cold start, is it like turning the engine off, or a stall in power delivery, in my experience turbos rarely fail in a lightswitch type effect, they either have full power or a shade of it, never like an ignition cut,
[QUOTE=feraldisco]thanks - I'll make sure turbo wastegate is operating correctly (I have a new turbo boost modulator but I'm not convinced the actuator is working properly, even though these apparently never bugger up) first and may revisit TPS. The thing that makes me think it's not the TPS is that I've never received a 'driver demand' error and the engine still cuts out a bit under cruise control.
cheers
was it doing it before the chip, and does it do it worse after flogging the car, what is your fuel consumption?
[quote=feraldisco]hoses are ok, no soot when trying to rev it passed 2500 (only occasionally get soot when accelerating hard from lower revs and between gear changes, but put this down to new chip).
It's a 99 manual with only 140,000kms and I know that the motor itself is in good nick as it's super smooth (smoother than any other Td5 I've driven) under 2500 and it gets 85wkw on the dyno (usually only get 75-90wkw from a TRS chip). I run a snorkel with standard paper filter, but thinking about getting one of the Td5Alive foam air filters...
[QUOTE=SO69WA]Yes its possible there is more than one battle being fought here, and i do think that the tps should be a serviceable item changed every 5 years min, ie like sparkplugs they still might run , but gees do you notice when you put new ones in.
turbo problems are rare indeed, given the unit we run, providing its well oiled and exercised often, normally blown or caviating/ delaminating inlet hose are the issue here, so check them, see if you can verify wether at these low power moments, there is excesive soot from the exhaust in the rear view
does the issue occur if you leave your foot flat,
oh are you manual or auto, do you have snorkel and clean wet type air filter, how many ks and who were previous owners
[QUOTE=feraldisco]It's a constant issue pretty much, hot or cold and in all gears - runs rough and just doesn't accelerate smoothly between 2500 to 3000...will sometime accelerate hard beyond 3000, but sometimes just rough and no extra acceleration without really pushing it. I don't think the turbo itself is the problem, but it's possible that the ECU is cutting power due to sensing overboost. I've replaced the turbo boost modulator, freed up the wategate and played around with wategate rod length - none of which seemed to make much difference. It may be a faulty wastegate actuator/valve and I'll test this on the weekend. Don't think it's a fuel problem as fuel pressure is fine. Will test MAP, AAP, TPS and wastegate valve more thoroughly. Tempted to just replace TPS anyway for $170...
Quote:
Originally Posted by SO69WA
well they upgraded the two track TPS on your 99 to a three track on mine, update 2003 so we can rekon theyre suss and may indicate why your symptoms are more severe, my three track was spose to verify its pos, and maybe be more robust but obviously can still crap itself as well,
ENGINE MANAGEMENT SYSTEM - TD5DESCRIPTION AND OPERATION 18-1-19Throttle Position (TP) sensor– From VIN 297137
Discovery Series II vehicles from VIN 297137 use three track thick film potentiometers. No idle speed sender switch
is used on this type of sensor because the ECM can compare the two or three sets of signals to implement idle speed
control and over-run fuel shut-off. The two potentiometers are known as track 1 and 2 potentiometers. The track 3
potentiometer on later models is used to improve the resolution of the pedal. The ECM provides a 5V supply and
receives a signal from each of the potentiometer tracks.a= Track 1
b= Track 2
c= Track 3
d= Voltage
e= Pedal angle (degrees)
f= Wide open throttle stop tolerance band
g= Not applicable for Discovery Series II.
With reference to the above graph, at idle (throttle released), track 2 returns a signal of 4.2V to the ECM and track 1
returns a signal of 0.8V. The ECM calculates the sum of these two figures which totals 5.0V.
At wide open throttle, track 2 returns a signal of 1.1V and track 1 returns a signal of 3.9V to the ECM. The ECM
calculates the sum of these two figures which totals 5.0V. The ECM uses this strategy to error check the TP sensor
signal and ensure that the requested throttle position is applied. The third potentiometer track measures the tolerance
of tracks 1 and 2 and provides an improved functionality check of the pedal angle.
NOTE: Three track TP sensors cannot be fitted as replacements on vehicles previously fitted with two track TPIf the TP sensor fails, the ECM will illuminate the MIL and the engine will operate at normal idle speed only.
sensors. Replacement ECM's are configured for two track TP sensors and can be fitted to all Td5 models. When
replacement ECM's are fitted to vehicles using three track TP sensors, TestBook or T4 must be used to configure the
ECM for three track TP sensor use.
[QUOTE=feraldisco]yep, same roughness/struggling characteristics before and after chip - the chip has just given me a bit more bottom end oomph as I can't really access over 2500! Hence I also get rather good fuel economy and it's not really an options to flog the car, as short shifting is a necessity - it feels very coarse and unpleasant over 2500 so I don't like going there...