Freelander TD4 Lack Of Power

Yipee! I've fixed it!!!

It was the inlet manifold pressure sensor, more commonly known as a MAP sensor.

I'd taken the inlet manifold off to look at replacing the HP fuel sensor wiring loom, it's a bitch of a job, looks like you unplug the original plug then ignore it, run the new bit of loom to the ECU box, drill a hole in the side, then attempt to remove 3 wires from one of the ECU connectors to replace with the 3 wires in the new bit of loom. Didn't do mine, the plug and loom looked fine, and I wasn't gonna mess with the ECU connectors. While the manifold was off, it was easy to remove the MAP sensor, the end looked messy, so I poked a cotten bud into the hole in the manifold, what a mess in there! Was all bunged up with black tar like crap, I'm not sure if it was this crud preventing the sensor measuring the pressure or the sensor was duff, but once I'd cleaned out the manifold a bit, replaced the MAP with a new one, new gaskets and put it all back together, it ran fine. Thank god! Perhaps a job for the future will be a decent clean out the inlet manifold. The car has only done 62K miles, I'm surprised by the amount of carbon and gunk in there. I can only guess it's from the EGR valve, I now have a bypass fitted, so at least the muck won't get worse.

Refitted the Rover Ron Synergy box too, though haven't connected it to the MAF as it's a brand new LR unit, so I guess there's no point?

Anyhow, thanks to everyone for suggestions on what to look at!

Alan C

Good news that. Shame about all the expense but at least you know you've got a reliable motor now.

That's another fault I've made a note of.....thanks for the feedback.....

Yes! Great news. I have been following this thread with great interest, as I'm sure many others have! However, I cannot find a reference to a MAP sensor for a TD4 in Rave or Haynes. The nearest I can get is the Boost Pressure Sensor, which would tie in with Yorkshire Hippo's thread where a problem was observed with a laptop with boost pressure - and correct operation can be seen by looking at the operation of the actuator on the turbo, as mentioned previously? Very useful tip for future diagnosis.
Eric.

Yorkshire Hippo? Where did I get that from?? Sorry Shropshire Hippo, I've moved your county! (That's what living in Essex does for you!)
Eric.

MAP = Manifold Pressure Sensor, Land Rover don't call it this, they call it a boost presure sensor. Indirectly it does control the actuator on the turbo, but via the ECU, but it does also effect the fuel injection. Mine was still giving credable information to the ECU, but it was either faulty and reading low, or more likely, was partially bunged up. According to the diagnostics, tickover boost was fine, and it was raising as the revs rose, but I guess not high enough, so not enough fuel was being injected thus low power from the engine. As the values were believable to the ECU, no fault code was generated. At least I hope this is the cause! I'll find out over the next few days if the fault returns.

Alan C

Yes ! congratulations Alan , boost sensors all round it is then ! Had mine fitted today , sorted at last ! Took it for a blast this afternoon and after all the other parts that have been fitted it is flying Might even wash mine at the weekend now I'm talking to it again .

atvb Paul.

Well Done Paul, glad the boost presure solenoid fixed yours. The Boost pressure sensor is usually a very reliable piece of kit (unlike the boost presure solenoid, but I now know how to check these!), which is why I didn't change it till the very last.

Talking to my LR parts agent and returning the loan MAF to him, I cheekily asked if I could return the first supplied MAF, as I have a Pierburg and Synergy box, AND the original MAF, so I really don't need it, plus it cost me £200 + VAT, and he's hopefully gonna take it back less a small handling charge. That'll reduce the bill a bit if he does

Alan C

Well done Alan and many thanks for your perseverance and final feedback regarding the solution which will be so helpful to others in similar situations if only they will take the time to search the forum. Cheers and beers, Dann..

I think I earned myself a beer with this one! :beer2:

Another update! I have just removed the brand new Land Rover MAF and installed my Pierberg MAF and connected it to the Synergy box. Wow, what a difference! Much more power and better throttle response. I didn't expect this, I thought it would make no difference. So there you go, do what Rover Ron says and replace that rubbish Bosh MAF! I'm glad I had a chance to compare them. Now to get my LR Dealer to take it back for a refund.....

Alan C

Alan C said:

I think I earned myself a beer with this one! :beer2:

Another update! I have just removed the brand new Land Rover MAF and installed my Pierberg MAF and connected it to the Synergy box. Wow, what a difference! Much more power and better throttle response. I didn't expect this, I thought it would make no difference. So there you go, do what Rover Ron says and replace that rubbish Bosh MAF! I'm glad I had a chance to compare them. Now to get my LR Dealer to take it back for a refund.....

Alan C

Click to expand...

What did you do with the temperature sensor on the box ? (If one of course). I understand the Bosch has a temp.sensor in it which the Pierburgh hasn't and therefore the synergy box has, I believe, a separate sensor ?

There's a seperate small cable with a temperature sensor at it's end, simply drill a small hole into the airbox somewhere near the MAF so it can poke into the air box. If needed, a small bit of silicone sealer will hold it in place. I wouldn't leave it outside the air box as all it'd then measure is the underbonet air temperature, not the inducted air temperature. It's all very easy, and the rest is plugged in, a few cable ties and it's all done.

Alan C

Thanks Alan, and have fun with the newly acquired power....

BTW, From March 2009, the temperature sensor is inside of the 5-pin plug and not as a separate unit... Just to make sure ;-)

hi guys,

sorry im new to the forum. are you talking about the td4? im having problems with mine. one min it will be driving finr the next it wont go past 3250rpm! and because its an auto it wont change gear!

hope you can help

gwyn

hi reading your threads about td4 engine not revving i have a problem with my td4 it strarts but will not rev over 1400 it just cuts out its had new high pressure pump ,injectors , cam and cranks shaft sensors ,maf sensor . if you start it and keep your foot down on throttle it just revs slowly then dies then revs then dies and revs again just keeps on doing this any ideas as i am now lost thanks ian

Ian,

You'll need a diagnostic system to interigate the ECU to look at any fault codes first, and if non then to look at live data from the various sensors. I'm a bit puzzled in you having fitted pumps, injectors and sensors blindly, unless you were following my problem in that the diagnostic system wasn't helping?

Hi. Sorry to dig up an old thread but I have exactly the same problems with mine ATM. And the garage has now run out of ideas.

How would I go about changing the map sensor or boost pressure sensor? Is it a fairly easy job?

Thanks Dave

The MAP sensor and the boost pressure sensor are both fairly easy to change, order the required sensor and once it's in your hands you'll see how it fits. The engine cover has to come off first, the MAP sensor is located at the top left of the engine as you're looking at it, in the air intake duct , the boost sensor is screwed into the inlet manifold mid left of the engine, I think, from memory. Both are fairly easy to access.

Thanks Alan. Maybe some confusion on my part, from what I have read the map sensor and boost sensor are the same thing some people just call them different names. I have already replaced the MAF sensor (well it's had three genuine ones actually to make sure there not faulty)

Will get a boost sensor ordered and give that a try if that fails I'm all out if ideas as it's had high and low pressure fuels pumps changed, new injectors, new turbo and had the ecu sent away to be checked. All to no avail as it's still exactly the same.

Hopefully this may cure it as my symptoms are identical to the ones in thus thread.

If not I think it's scrap.

Thanks Dave

Sorry, I think I have got MAF and MAP muddled up. My findings on the MAP sensor was that mine was bunged up with a tar like substance which seems to coat the inside of the inlet manifold, most probably semi unburnt exhaust products coming through the EGR valve assembly. Although I didn't actually check on the live diagnostic figures, I believe the ECU was receiving a low value from this sensor, but still within tolerance, hence the ECU wasn't injecting enough fuel for the amount of air reaching the engine causing very low engine power but no MIL light. I did scrape out most of what I could from the inlet manifold and replaced the sensor with a new one and the fault was cured. Lets hope your problem is the same. Please report back once you've replaced your sensor?