I need help - or ‘they’ will take me away…soon.

I have Defender 90 from the year 2000 and have been facing the following problem for more than a year now. I hope you fellow people may have the wisdom needed to ease my pain.

Symptoms:

At low rpm (1500-2000) the car has an uneven speed. It feels like a gentle flutter/stutter/surging energy. The throttle is very very sensible. If I drive on an uneven surface the energy transferred through the suspension, the chassis and finally the throttle is enough to amplify a stutter even if I do my outmost to keep the throttle position fixed. When releasing or engaging the throttle it feel like there is too much slip in the transfer line which amplifies the stutter/surging feel.

I often choose a higher gear to lower the rpm when cruising in towns – exactly to avoid the very stutter low speeds. So the stutter is most often not present below 1500 rpm.

Above 2000 rpm the stutter is amplified but In the following video links you may see the problem ‘live’ ) The vidz show fairly high rpm as the gentle stutter at 1500-2000 rpm is difficult to catch on video.


[nomedia="http://www.youtube.com/watch?v=NYeHbdGSswc"]Defender 90 stutter 003 - YouTube[/nomedia]

[nomedia="http://www.youtube.com/watch?v=YvkA7IBvQBw"]Defender 90 stutter 001 - YouTube[/nomedia]
[nomedia="http://www.youtube.com/watch?v=q5CKSFyglUM"]Defender 90 stutter 002 - YouTube[/nomedia]

When full throttle (while accelerating etc – there is nothing) As long as I either accelerate or use the engine brake – no problem. If trying to reach a steady cruise speed the car feels like fluttering between accelerating and engine braking.

The problem are also present in low range and even more significant when driving off-road due to the uneven surface. It is very difficult to keep a steady low speed pace at 1500-2000 rpm.

I never feel an actual loss of power.

General stuff and actions so far:
TD5, EGR removed, Silicone hoses,

Alivetuning stage II remap (intercooler + remap) fitted some two months ago.
The symptoms are the same but somehow amplified by the increased engine power.

Diagnosis shows no faults. MAF, AAP, clutch sensor and injector readings show correct data.

Injector harness exchanged (2010). No oil in the connection below the top engine cover (just checked today)

Clutch and mass fly wheel exchanged beginning 2010.

Front diff refurbished. Excellent condition (perfect slip)
Rear shafts exchanged with Aschcroft HD shafts and new HD flanges (no slip in splines)
Propshafts balanced. U-joints are ok.

Crank position sensor cleaned.

Wastegate oiled up. Works fine.

There is no significant noise from the drive line – only a gentle whine which I assume is a bearing somewhere.

Within the last few weeks: Fuel pressure regulator, Throttle pedal (w. sensor), clutch sensor, MAF sensor and ECU! replaced!

The turbo pressure has been tested and it looks fine. Starts at 0,2 bar and steadily increases to 1,2-1,3 bar without jumps etc. No sign of over-boost.

App 8 hours of fault investigation at a workshop – no result. They believe it was the ECU which I now believe - it is not. When first testing a new ECU – it was without the remap and the fault was less predominant as now when the new ECU has been fully remapped again. The problem feels the same.

.....................

I’m at the end of the rope now and have tried a lot of things based on knowledge I have harvested online.

Please let me know my thoughts…

Thank you all!
Lars Rindom Jensen

What about the turbo wastegate modulator?... quite common issue for td5

I believe there is no modulator on the Defender .. only on the Disco. The wastegate on the Defender is driven by a pressure hose..

?? right ??

Lars

Buckhandle said:

I believe there is no modulator on the Defender .. only on the Disco. The wastegate on the Defender is driven by a pressure hose..

?? right ??

Lars

Click to expand...

i believe you are correct

the wastegate modulator is part of the td5 turbo on defender too... at least according to microcat, PMK100130 see aplicable models PMK100130 DISCOVERY TURBO WASTE GATE VALVE ASSY | Defender 1985> | shop | www.lrseries.com | L. R. Series

i read somewhere the throttle position sensor has 2 settings, one for on road, one for off road and if wired incorrectly make the vehicle very twitchy

sierrafery said:

the wastegate modulator is part of the td5 turbo on defender too... at least according to microcat, PMK100130 see aplicable models PMK100130 DISCOVERY TURBO WASTE GATE VALVE ASSY | Defender 1985> | shop | www.lrseries.com | L. R. Series

Click to expand...

mine doesnt have a moddulator, its a1999 td5 defender

I will not argue with a defender owner on this

johnlad said:

i read somewhere the throttle position sensor has 2 settings, one for on road, one for off road and if wired incorrectly make the vehicle very twitchy

Click to expand...

good point but i dunno about off/on road settings i just know that there are two type of sensors, for pre and post EU3 modells ... putting the wrong sensor might make some trouble ... the plug is the same but there are differences between the inputs in the ECM.

Replacing the throtthle sensor made no difference. Yet I agree - there are two types of sensors w. either two or three potentiometers. The new ECU is one of the 'newer' models which can be remapped without replacing the actual chip. When fitting the ECU we needed to program it for the two-sensor throtthle sensor - so it should be all right. Anyway there is no difference to the problem - no matter new ECU or throttle sensor...

In terms of the high/low range issue: There is a on/off sensor on the transfer gear box. When engaged in low range the ECU will use the throtthle input differently than if in high range. So the input from the throttle is actually the same as I understand it. Good point though. If the sensor or a wire has a problem the ECU may switch between the high/low range mode. I will keep you posted.

Keep the good ideas coming guys!

Thank you,
Lars

Bypassed the hi/low sensor today and it made no difference. When in Hi gear yet having the sensor bypassed (making the ECU belive it is actually in Low) reduced the stutter - yet the problem is still there. The stutter may have been reduced by this initiative - but is not the root cause....

Lars

Bump (sorry)

Buckhandle said:

I need help - or ‘they’ will take me away…soon.

I have Defender 90 from the year 2000 and have been facing the following problem for more than a year now. I hope you fellow people may have the wisdom needed to ease my pain.

Symptoms:

At low rpm (1500-2000) the car has an uneven speed. It feels like a gentle flutter/stutter/surging energy. The throttle is very very sensible. If I drive on an uneven surface the energy transferred through the suspension, the chassis and finally the throttle is enough to amplify a stutter even if I do my outmost to keep the throttle position fixed. When releasing or engaging the throttle it feel like there is too much slip in the transfer line which amplifies the stutter/surging feel.

I often choose a higher gear to lower the rpm when cruising in towns – exactly to avoid the very stutter low speeds. So the stutter is most often not present below 1500 rpm.

Above 2000 rpm the stutter is amplified but In the following video links you may see the problem ‘live’ ) The vidz show fairly high rpm as the gentle stutter at 1500-2000 rpm is difficult to catch on video.


Defender 90 stutter 003 - YouTube

Defender 90 stutter 001 - YouTube
Defender 90 stutter 002 - YouTube

When full throttle (while accelerating etc – there is nothing) As long as I either accelerate or use the engine brake – no problem. If trying to reach a steady cruise speed the car feels like fluttering between accelerating and engine braking.

The problem are also present in low range and even more significant when driving off-road due to the uneven surface. It is very difficult to keep a steady low speed pace at 1500-2000 rpm.

I never feel an actual loss of power.

General stuff and actions so far:
TD5, EGR removed, Silicone hoses,

Alivetuning stage II remap (intercooler + remap) fitted some two months ago.
The symptoms are the same but somehow amplified by the increased engine power.

Diagnosis shows no faults. MAF, AAP, clutch sensor and injector readings show correct data.

Injector harness exchanged (2010). No oil in the connection below the top engine cover (just checked today)

Clutch and mass fly wheel exchanged beginning 2010.

Front diff refurbished. Excellent condition (perfect slip)
Rear shafts exchanged with Aschcroft HD shafts and new HD flanges (no slip in splines)
Propshafts balanced. U-joints are ok.

Crank position sensor cleaned.

Wastegate oiled up. Works fine.

There is no significant noise from the drive line – only a gentle whine which I assume is a bearing somewhere.

Within the last few weeks: Fuel pressure regulator, Throttle pedal (w. sensor), clutch sensor, MAF sensor and ECU! replaced!

The turbo pressure has been tested and it looks fine. Starts at 0,2 bar and steadily increases to 1,2-1,3 bar without jumps etc. No sign of over-boost.

App 8 hours of fault investigation at a workshop – no result. They believe it was the ECU which I now believe - it is not. When first testing a new ECU – it was without the remap and the fault was less predominant as now when the new ECU has been fully remapped again. The problem feels the same.

.....................

I’m at the end of the rope now and have tried a lot of things based on knowledge I have harvested online.

Please let me know my thoughts…

Thank you all!
Lars Rindom Jensen

Click to expand...

had similar problem with mine turns out to be copper washers on injectors diagnostic machines dont pick this up to good as injectors fire ok ecu gives out good signal cheep to replace worth a shot

Hi Mike! Thank you for your input! I actually just ordered copper washers, new o´rings and bolts (rocker shaft and injector) last week - just waiting for delivery! I am only pleased to learn that I might be working in the right direction!!

thx!! Lars

may also be important to check feul tank and pump for soot contamination as mine was full of it hope it all works out

I have now replaced the copper washers and o´rings on the injectors.
Unfortunately this has changed nothing.

The studdern/uneven driving pattern continues.

It still feel like the throthle is way too sensitive. In the beginning there is app 8-10 mm throttle movement without any engine response. Herafter the engine revs up slowly but around 1500 rpm it feels like only 2-3 milimeter of throttle movements boost the rpm up to 2200 rpm. I believe this is where the turbo 'kicks in'. Remember that the turbo boost pressure showed nice results and the wastegate works fine. The turbo bearings are good too and there is no signifficant oil consumption through the turbo. Could this be a turbo problem anyway/somehow?


If a electrical problem and not the throthle or the ECM ... what may cause this? Could the main loom cause such a problem (not the injector loom)??

In relation to the injectors (pictures): The end of the injectors showed some sediments/deposition as shown on the first photo. I belive this is normal? On the second photo I have wiped of the sediments and you can see some heat-colour on the copper washer. None of the injectors had sign of any exhaust gasses blowing back along the injector side. So I believe that both the copper seals and o´rings have been tight.

???

Lars

Update ...

Just ripped the engine harness out today - and ordered a new one. Crossing my fingers.

Lars

I'd check the crankshaft position sensor too... see this > "Voltage generation from the CKP sensor is relative to engine speed. The values expected from a good CKP sensorare as follows:
- 2 to 3 volts with engine cranking.
- Rising to 6 to 6.5 volts from 1000 rev/min upwards.
The above readings are dependent upon correct air gap between the tip of the CKP sensor and the passing teeth of the reluctor ring."

It might sound a silly question, but do you only get the stutter when the vehicle is under load, i.e. at the same engine revs in neutral does it run smoothly?

Tazz

Has it had a new flywheel lately? How many miles has your flywheel done? Seen it before on tdi VW, when flywheel gets worn it moves about a lot more and gives an uneven signal to the flywheel sensor! Just a thought!