Td4 Lack of power at 70mph - fixed !

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Kungfu0210

New Member
Posts
124
Location
Warwickshire
Hello all, just thought i'd update you on the cause of my lack of power issues with my Td4 03MY in case it helps anyone.

I initially had a split turbo hose whilst on the M6. It was the short 90 deg hose. Symptoms were initially lack of power, and then black smoke and air whistling sounds. Bought a new one of those for under a tenner and fitted it.

Unfortunately it didn't fix the lack of power over 70mph, but at least there was now no smoke. Symptoms now were that on a slight gradient on the motorway the car would start to lose power and thus speed. There was also a slight noise but not the same as the air noise from the split before.

The Td4 turbo is variable geometry and is controlled by the boost solenoid (see black plastic unit in the picture). It applies a vacuum to the turbo via pipe 1 in the photo. When the vacuum is applied the turbo exhaust side vanes close and it uses more exhaust gas to provide more boost.

My solenoid had failed so that it constantly applied vacuum to the turbo, and thus operated it at max boost all of the time. What then happens is that when you get a high speed / load condition i.e. 70mph and a hill, the ecu senses that the turbo is over boosting and derates the engine by cutting the fuel in order to protect it from damage. It will then speed up again when you get back onto the flat.

The solenoid is STC4198, cost £34, took 15mins to fit (don't need undertray off). Fitted and all working perfectly now.

So if you have lack of power on hills at 70mph, try this test. Pull pipe 1 off the turbo and drive a 70mph hill and see if it cures your issue. If it does, voila it's the boost solenoid. With the pipe off it will be a little sluggish at low speed accels as it won't be able to close the vanes for full boost, but it's fine to drive in order to do your 70mph test.

For info pipe 1 is solenoid vacuum to turbo, pipe 2 is vac supply to solenoid from the plastic reservoir at the side of the engine, pipe 3 is the solenoid vent to fresh air via the little filter. Check these for holes as they rub various engine parts. Also worth checking that your boost solenoid filter isn't blocked, as this would prevent the solenoid from releasing the vacuum and cause the same symptom. Fair chance it's ok though and your solenoid is bust.

Good luck ! :)
 

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Kung,
did you read fault codes at any stage? I thought it was the change of the 'angle of attack' that the variable vanes produce that varies the speed of the turbo, and, therefore the boost pressure. Or is it a combination, quantity and 'angle'? I will look it up when I find time!
 
The picture was taken from where pse ?? (Just to know where all this can be seen/found ??) Thanks.
 
Radnorman...

I have got a USB code reader from China via Fleabay but it says that there are no codes in there. Whether it's really no codes, or whether that's my dodgy Chinese code reader, who knows.
Yep it's the angle of the vanes in the exhaust side of the turbo that varies how much it spins up and thus how much boost you get. My description of open / closed was a bit misleading.

Willo...

If you lie on your back under the drivers door i.e. behind the front drivers side wheel and look up at the back of the engine, that's where I took the photo. There's fairly easy access to it from there as the undertray stops just before that point so you can reach up without removing it.
 
Kung, where did you buy this item?

Torsen


Hi, I bought my boost solenoid from Trinity Motors in Hinckley. It's supposed to be about £41 + Vat but he said he'd sort me a cash discount, and it ended up as about £34 incl Vat which was a good result. The parts bit of Trinity is down the side of the place, not within the main LR dealership itself.
 
Trouble with that is you have to go to the common Q&A to find it, when you've just taken the obvious step of visiting the Freelander forum.

Ere, what about putting this thread in the Common Q&A forum and then putting a sticky link in the Freelander forum to take you to the Common Q&A forum?
 
Trouble with that is you have to go to the common Q&A to find it, when you've just taken the obvious step of visiting the Freelander forum.

Ere, what about putting this thread in the Common Q&A forum and then putting a sticky link in the Freelander forum to take you to the Common Q&A forum?

It's now sticky here.:)
 
Hi, did you have trouble at low speeds pulling out of junctions as well? I have the same at 70mph but also like the car is fighting acceleration at take off ( sets off then slows like under load ). Mine is automatic so its like foot to the floor and pray.
Cheers Steve
 
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Cheers Willo but trying to find out what "MAF" is and do you disconnect electrically or pneumatically. Is it the item at the top of the vacuum tube shown in the original fault of lack of power at 70mph?
Cheers steve
 
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