Torque Problems

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dreas

New Member
Posts
18
Location
Jamaica
Hi All,

I recently had an issue with my Disco II where I got zero torque when car was in gear and accelerator pressed - car would rev, but no torque what so ever (automatic transmission).

first diagnosis i got from mechanic/diagnostic computer here was that the fuel pump was faulty, so we changed this, but it made no difference (in hindsight i dont actually think the pump was gone).

after searching some forums including this one, we changed out the injector harness / loom wire after having read that oil spray can penetrate this and cause a short circuit.

voila, torque was back... somewhat. i now have a new / other issue. the car drives, gears change, and everything seemed fine, until i tried to overtake on an uphill over the weekend. i floor the gas, the car gears down, revs go up, but i do not get any additional torque. transmission also stays at around 2.5-3K and does not change back to a higher gear unless accelerator released slightly.

any idea what this may be related to..? could it be the new fuel pump (faulty?), or maybe the harness or incorrect installation of it, or would this be something totally new / different? any help is appreciated. other than that everything seems fine
 
I agree with above have you checked you oil in box . And if your not happy doing a oil check you Could also do a quick test does the car try to creep when put in D on tick over and or can it hold itself on a small incline in D . If no then get the oil in box changed before you try anything else .
 
Turbo waste-gate sticking partly shut, causing over-boost and the engine management to cut fuel. Had it on our TD5 auto, it wouldn't go past 3000 RPM and change up unless you backed off the accelerator.
 
might be a clutch slip too... but the oil/filter change must be the first call, if no joy after that run a stall test on it maybe you'll get an answer
Stall test

Testing
1. Chock the wheels and fully apply the
handbrake.
2. Start the engine and run it until it reaches
normal operating temperature.
3. Apply the footbrake and select 'D'.
4. Fully depress the accelerator pedal and note
the tachometer reading. The figures should be
as given below.
- V8: 2200 to 2400 rev/min
- Diesel: 2600 to 2800 rev/min
5. A reading below 1300 rev/min indicates a
torque converter fault, ie stator free-wheel.
6. A reading between 1300 and 2200 rev/min (V8)
or between 1300 and 2600 rev/min (Diesel)
indicates reduced engine power.
7. A reading above 2400 rev/min (V8) or above
2800 rev/min (Diesel) indicates clutch slip.
Do not carry out stall test for
longer than 10 seconds, and DO NOT repeat
until 30 minutes have elapsed.
NOTE: The figures quoted above were
measured at sea level with an ambient
temperature of 20 °C (68 °F). At higher altitudes
or higher ambient temperatures, these figures
will be reduced.
Click to expand...
 
dreas said:
Hi All,
transmission also stays at around 2.5-3K and does not change back to a higher gear unless accelerator released slightly.
Click to expand...

Could be overboost (possibly due to knackered boost valve - easy to fix). Certainly that's exactly how I would describe the overboost symptoms I experienced - just refuses to rev when you put the boot in, almost like it's on a limiter
 
thanks all for the quick feedback. am away on business for a couple of days but i will look in to all recommendations when back and report back asap
 
GDM said:
Here is my post when I had a similar issue: -

http://www.landyzone.co.uk/lz/f8/td5-lack-power-under-load-186699.html

Like I say, after worries about the auto 'box, it was a sticking waste-gate that took just a squirt of WD40 and a wiggle with some grips to fix.

It could also have been the waste-gate modulator though but that made no difference on ours.
Click to expand...

Thanks GDM, very helpful. I noted in your thread that there were references to the air filter... mine was changed at the same time the injector harness was changed, so could the issue be related to that also? ie maybe incorrectly / poorly fitted, or something? Also, the car is due a a regular service - 3000 mile service, but gone 5K (I know, i know, please no preaching...) so could that also be related (though I have gone without a service for 5K miles before)..?

as i said, the problem only really came in to play once the new fuel pump, injector harness and air filter were fitted to take care of the original problem...
 
dreas said:
Thanks GDM, very helpful. I noted in your thread that there were references to the air filter... mine was changed at the same time the injector harness was changed, so could the issue be related to that also? ie maybe incorrectly / poorly fitted, or something? Also, the car is due a a regular service - 3000 mile service, but gone 5K (I know, i know, please no preaching...) so could that also be related (though I have gone without a service for 5K miles before)..?

as i said, the problem only really came in to play once the new fuel pump, injector harness and air filter were fitted to take care of the original problem...
Click to expand...

If you read my thread, the fuel pump failed on ours just before the problem occurred, although it was, undoubtedly, a complete coincidence.

I even suspected a faulty replacement pump as well.

Try freeing the waste-gate, then if that doesn't work replacing the boost modulator, it's only about £25-00.
 
So I came back from my trip and wanted to start dealing with the issue only to find that the disco now goes straight in to limp mode (M&S lights flashing) as soon as I start her up. The car will go in to gear - ie there is torque when I put it in to gear, but just at the reduced (limp mode expected) level.

Repetitive turning on and off of ignition has no effect and the lights will start flashing within seconds of turning on car even without selecting any gear.

Thx in advance for an help. Driving me nuts and thinkng very seriously about getting rid of her - but she is like a bad girlfriend - hate her but love her and don't want to let go. Not to mention there are no viable replacements out here.
 
Ok, so did some reading and low voltage seemed to be one cause. The car had been sitting for a while so I let it idle for a bit (with lights flashing) turned it off and back non and voila, no flashing lights, for now..... Let's see
 
dreas said:
Ok, so did some reading and low voltage seemed to be one cause. The car had been sitting for a while so I let it idle for a bit (with lights flashing) turned it off and back non and voila, no flashing lights, for now..... Let's see
Click to expand...
Put the battery on charge, the alternator will take a very long time to fully charge a flat battery.
 
Hi All - quick update and follow up question.

Torque problem solved which was down to the replacement fuel pump being faulty. So replaced it again witha second hand original and everything is fine.

M&S light blinking and limp mode is down to faulty XYZ / inhibitor switch. Question I have is can I order one from the states which is for the petrol model - ie gasoline - when my car is a diesel TD5 UK spec? They are a lot cheaper and I can get my hands on one a lot faster living in Jamaica.
 
Thanks sieraferry. Will get one now, maybe even two just in case. New ones are damn expensive so hoping for a good / clean used one on ebay.

May play around with my oldie and the above instructions though I have never been good at taking stuff apartment - all of my damaged Walkmen growing up are testaments of that lack of skill...

Appreciate all the knowledge & help this forum has provided. You guys rock!
 
so i hav been looking at the xyz switch. brand new they range from somewhere between US$650 - 800, or £280+

i can get them used in the US for around $100, most of which have a 30/60/90 day warranty.

Am i wasting my money buying it used, or used and refurbished?
 
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