TD5 lack of power under load.

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G

GDM

Active Member
Posts
205
Location
West Sussex
I have an ongoing problem with our 1999 TD5 Auto (115,000 mile).

It was running fine up until 4 weeks ago whe my wife towed our horse trailer back from taking our daughter to an event. She said that the car was seriously down on power, especially going up hills. I took it for a run with the trailer and it was, indeed, really struggling to pull up hills or under load. I tried it without the trailer and on light throttle it was fine but as soon as I put my foot down it refused to accelerate.

I changed the fuel filter and took it out for a run but only got about 200 yards before it died completely. I towed it back home and found the fuel pump was not running. Ordered a new Bearmach pump, fitted it, primed the system, and it started up and ran reasonably well.

We used the car for a few weeks (without towing), and it seemed to be fine but going up a steep hill last Wednesday I felt it was still down on power.

Today I towed a plant trailer which weighs about 750Kg and it was immediately obvious that there was a lack of power. I picked up a tonne of ballast and cement and the car really struggled with that, again a real lack of power especially at any more than half throttle, and the lack of power is affecting the changes on the auto-box. It is particularly reluctant to get to 3000 rpm, and the revs seem to fluctuate slightly under load.

It seems that I might have an additional problem on top of the faulty fuel pump, either that or the new pump is not producing sufficient pressure. The pressure regulator was replaced about 40,000 miles ago.

I guess it could be a MAF or boost solenoid problem, although I did clean the MAF when it first played up. I will also try cleaning the inlet manifold sensor and the EGR valve tomorrow. Any other ideas before I admit defeat and lighten my wallet at the garage?
 
try with MAF disconnected...the EGR/inlet cleaning is a good idea...after that unplug the vacuum pipe from the EGR valve and clog it well with a rivet or something(this way it will stay closed)

put new air filter too

the best would be to see if there are some fault codes logged

when was the oil and filter changed in the autobox ? ...cos this is important too to be OK
 
sierrafery said:
try with MAF disconnected...the EGR/inlet cleaning is a good idea...after that unplug the vacuum pipe from the EGR valve and clog it well with a rivet or something(this way it will stay closed)

put new air filter too

the best would be to see if there are some fault codes logged

when was the oil and filter changed in the autobox ? ...cos this is important too to be OK
Click to expand...

Thanks for the reply.

I did try it with the MAF disconnected before I replaced the fuel pump and it made no difference but I will try it again. Will also try plugging the EGR pipe later today.

Air filter is a K&N one, and I cleaned and re-oiled that when it first played up.

Auto'box oil has been changed within the last year or so, which did make a difference to the smoothness of the box and the timing of the changes. I don't think that there is an issue with the 'box, I think it is being thrown by the engines lack of power.

Yes, fault codes would be good but I am trying to avoid going to our local Land Rover specialist as they are very expensive. Will ask the local garage if they have the equipment to do it.

I have read about the hose from the MAF sensor to turbo being sucked in under load, so I guess it could be this. There certainly seem to be quite a few specialists selling them.
 
Are you sure it's the engine down on power and not just more slip in the Torque Converter (TC) part of the auto-box?

When towing, do you select D or 3? I found towing in hilly country it was much better to select 3 - because the TC locks up at a lower speed (approx 45mph) and therefore gives much better drive.

We tow horse trailers so I understand where you are coming from.

Incidently as someone else has suggested, it's worth changing your air filter for a new one plus changing the Mass Air Flow(MAF) for a new one- I buy my off Ebay for about £30 and they work very well.

Dave
 
thebiglad said:
Are you sure it's the engine down on power and not just more slip in the Torque Converter (TC) part of the auto-box?

When towing, do you select D or 3? I found towing in hilly country it was much better to select 3 - because the TC locks up at a lower speed (approx 45mph) and therefore gives much better drive.

We tow horse trailers so I understand where you are coming from.

Incidently as someone else has suggested, it's worth changing your air filter for a new one plus changing the Mass Air Flow(MAF) for a new one- I buy my off Ebay for about £30 and they work very well.

Dave
Click to expand...

Dave,

Pretty sure it's the engine and not a problem with the TC.

I do sometimes select lower gears when towing, and I did try that when it first played up but it made no difference. It's quite weird, if you use a light throttle you can accelerate gently but if you floor it you get no acceleration.

As I said, it has a K & N airfilter which I have cleaned and re-oiled, so that shouldn't be an issue. Might have a look at the MAF sensors on e-bay, for that price it would be worth a try.

Glen.
 
If the problem is occurring at high throttle openings, I'd be thinking of a stuck wastegate. Not experienced this myself but there was a thread on here about 4 months ago where the poster thought his auto was stuffed, but it turned out to be the wastegate.

Cheers!
 
GDM said:
Dave,

Pretty sure it's the engine and not a problem with the TC.

I do sometimes select lower gears when towing, and I did try that when it first played up but it made no difference. It's quite weird, if you use a light throttle you can accelerate gently but if you floor it you get no acceleration.

Glen.
Click to expand...

If you get the revs rising a lot but no forward surge when you floor it, that's a clear sign of the TC not working right.
Dave
 
You say you cleaned your air filter and re oiled it I've read that this can cause issues with fuelling as the k&n oil can contaminate the maf sensor wire giving the ecu false readings and screwing up the fuelling causing possible damage to the engine, might be worth a look .
 
Had a look at the car this afternoon.

Checked the wiring between the MAF plug and the red plug on the ECU as per Sierrafery's post, no problems here. Also no sign of any oil contamination in the red plug.

Took out the pressure sensor in the manifold, it was covered in muck, so I cleaned it with carb cleaner and re-fitted it.

Checked the EGR valve, this wasn't too mucky but I pulled off the vacuum pipe and blanked it off to eliminate it.

Took out the air-filter and checked for blockages between the air box and the intake point on the inner wing, no problems here.

Also checked for any split vacuum hoses.

Took the car for a run and it seemed to be fine until I went up a fairly long gradient at about 50 mph and tried to accelerate. Then it was the same, reluctant to accelerate and with a slight fluctuation in revs of about 100 rpm, almost like a rev limiter. It did then kick down and accelerate slightly. Obviously towing a trailer shows it up much more due to the additional load.

Looking at the MAF sensors on e-bay one of the symptoms listed for a failing MAF is like hitting a rev limiter, so I might change it to eliminate it, and perhaps do the same with the turbo boost solenoid as that is only £20.
 
Fitted a new MAF and new wategate modulator last night and took the car for a run up the same steep hill this morning.

The problem is stil there, in D it gets to just under 3000 RPM (about 50-55 MPH) and the revs drop about 100 RPM rise and then drop again, the car is in 3rd gear at this point. Putting it in 3 makes no difference but if I select 2 the revs rise to just under 4000 RPM and it will accelerate again.

Will have to get some fault codes recorded, as I am now rather stumped!
 
I'm having Major power issues with my D2 also! and its mapped!

Will be doing the injector harness again this week - thats what it was last time, i also have an issue with the revs over shooting and no power, revs will fly up between 200-300 revs but the car deosnt move with them, these cars have far to much electrical rubbish in them! will update if i solve the problems similar to yours!

D
 
99claydond said:
I'm having Major power issues with my D2 also! and its mapped!

Will be doing the injector harness again this week - thats what it was last time, i also have an issue with the revs over shooting and no power, revs will fly up between 200-300 revs but the car deosnt move with them, these cars have far to much electrical rubbish in them! will update if i solve the problems similar to yours!

D
Click to expand...

Doesn't the injector harness also cause rough running? I don't have this, just the lack of power under load. Probably should change it really, had the car from 68,000 miles and as far as I know it has never been changed.

From what I understand, all of the electrical controls are needed for modern diesels to pass the emissions standards. It can only get worse.

Yes, please update me if you solve yours, and I will do the same.
 
I got the fault codes read on Sunday evening by a Discovery enthusiast.

The car drove fine on the way there except for the fluctuation in RPM up one particularly steep hill.

The fault codes logged for the engine were: -
F3129 Road speed missing.
F3143 Turbo overboosting.
Open circuit on all injectors.

The fault codes logged for the gearbox were: -
F4023 Gear information not plausible.
F33 Engine torque invalid.

All the faults were cleared and the car taken around the block, then checked again but no faults logged. I then took it back up the steep hill again twice but on both occasions no fluctuation in RPM and what seemed to be normal power. This time the only fault code logged was on the gearbox, F33 Engine torque invalid.

The guy who read the codes suggested that I do the stall test on the 'box, to see if there is a problem with the torque converter or clutch. Although when towing a heavy load we have occasionally had the ATF temperature warning light come on, it has recently been coming on for a few seconds when not towing, so I am thinking that it might be wise to do another fluid change, perhaps to a heavy duty synthetic ATF, and to also change the filter.
 
GDM said:
I got the fault codes read on Sunday evening by a Discovery enthusiast.

The car drove fine on the way there except for the fluctuation in RPM up one particularly steep hill.

The fault codes logged for the engine were: -
F3129 Road speed missing.
F3143 Turbo overboosting.
Open circuit on all injectors.

The fault codes logged for the gearbox were: -
F4023 Gear information not plausible.
F33 Engine torque invalid.

All the faults were cleared and the car taken around the block, then checked again but no faults logged. I then took it back up the steep hill again twice but on both occasions no fluctuation in RPM and what seemed to be normal power. This time the only fault code logged was on the gearbox, F33 Engine torque invalid.

The guy who read the codes suggested that I do the stall test on the 'box, to see if there is a problem with the torque converter or clutch. Although when towing a heavy load we have occasionally had the ATF temperature warning light come on, it has recently been coming on for a few seconds when not towing, so I am thinking that it might be wise to do another fluid change, perhaps to a heavy duty synthetic ATF, and to also change the filter.
Click to expand...

Hi there it's Dave again. I'm still thinking this is a gearbox related problem. I want to give you some basic info and then a couple of tests.

Basic info: - the TD5 has a 4 speed electronically controlled auto gearbox with Torque Converter (TC). The TC locks up in 3rd and 4th gear at varying speeds dependant on throttle demand. On light throttle in 3rd at approx 48mph and in 4th at approx 55mph. Once TC lock-up is in place the revs should stay much more closely related to road speed, rather than that "clutch slip" feel of of spilling revs.

Test: - Find a quiet piece of road and with the engine and gearbox warmed up, select 3 and drive up to 50 mph then ease off the throttle until you have just enough to maintain speed. It should now go into TC lock-up - which feels like it's selecting the next gear and the revs should drop approx 600rpm. Does it do this?

Then select D and drive up to 55-60mph and ease off the throttle to just enough to maintain a speed above 55mph - again it should feel like it has selected a form of overdrive (it hasn't it's just the TC locking up as it should).

What results do you get with these tests?

Dave
 
thebiglad said:
Hi there it's Dave again. I'm still thinking this is a gearbox related problem. I want to give you some basic info and then a couple of tests.

Basic info: - the TD5 has a 4 speed electronically controlled auto gearbox with Torque Converter (TC). The TC locks up in 3rd and 4th gear at varying speeds dependant on throttle demand. On light throttle in 3rd at approx 48mph and in 4th at approx 55mph. Once TC lock-up is in place the revs should stay much more closely related to road speed, rather than that "clutch slip" feel of of spilling revs.

Test: - Find a quiet piece of road and with the engine and gearbox warmed up, select 3 and drive up to 50 mph then ease off the throttle until you have just enough to maintain speed. It should now go into TC lock-up - which feels like it's selecting the next gear and the revs should drop approx 600rpm. Does it do this?

Then select D and drive up to 55-60mph and ease off the throttle to just enough to maintain a speed above 55mph - again it should feel like it has selected a form of overdrive (it hasn't it's just the TC locking up as it should).

What results do you get with these tests?

Dave
Click to expand...

Dave,

Thanks for all that. I will try the test at the weekend and let you know how I get on.

Glen.
 
GDM said:
It was Dexron II rated not Dexron IID.
Click to expand...

The correct fluid as others have said was Dexron IID but it has been superceded by Dexron III

It is really important that you have the correct oil in the autobox.

Will you do the oil changes yourself? If you do, please remember that whilst the total capacity of the 'box is quoted as 9ltrs, you can only drain aprrox 4.5 ltrs at a time, the balance remaining in the torque converter.

For this reason I always to a drain and replace, then run about for a couple of hundred miles to mix up the new and old oil, the do another oilchange - it's not ideal but it's about the best a home mechanic without the specialist autobox oilchange kit can do.

If you are not familiar with the correct refill procedure please do ask, otherwise the 'box won't get correctly refilled and may cause damage.

Cheers
Dave
 
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