TD5 intermittent performance

[HowardSmall]

My 99 Defender TD5 generally runs fine. However on most mornings it has practically no power until it warms up. When I say practically none it can't even go up the small hill outside our house in first gear. Sometimes this does not occur.

When it does occur the performance is pretty bad for about the first km then OK.

On top of that it can be running fine, doing 100kph on highway, but suddenly it lacks power and accelerating from about 60 up can be a nightmare. I then have to go down the gears and get the revs up to be able to increase speed. Problem goes away in a matter of minutes.

Quite some time back I had the ECM upgraded and after that it would give a surge of power once the revs come up.

I am looking for any ideas on what could be causing the problem? Cleaning the loom where it connects to the ECM to ensure there is no oil there does not have any impact.

Thanks, Howard

[LandyAndy]

I would check the following,in this order.
Delaminating intercooler hoses????
Blocked/Water damaged air filter????
Oil in the harness????
AFM???(A member with a Nanocom can check its values to see if its OK)
Goodluck.
Andrew

[BilboBoggles]

I had this on my TD5, was caused by a dodgy AFM. To prove this I just disconnected the AFM, the TD5 ran a lot better without it. This indicated the AFM was stuffed. When disconnected the ECU takes a default map and uses it ignoring the AFM, if the AFM is buggered it should drive better. I tried cleaning it with contact cleaner etc, and this worked for a while. Best fix was a new genuine AFM, and it's been great since.

[Bundalene]

We had the same problem as BilboBoggles, with our TD5 D2 recently - loss of power at revs from one day to the next.

Swapped out the AFM after checking with an analyser and the problem was fixed instantly.

Howerer as Andrew says, check simpler things such as intercooler hoses first.


Erich

[HowardSmall]

After THREE YEARS of this driving me nuts and the performance getting worse it turned out that it was the Manifold Air Pressure/Temperature sensor! Changed it over three days ago and the problem has not recurred... It was Davis Performance who reprogrammed my ECU some eight years ago that put me on the right track - said the surging I was experiencing was typical of a MAP sensor failure.

In the meantime I changed the injector loom, replaced the MAF and fitted an EGR kit trying to fix it. Also replaced the shockers and had the roof lining fixed but they had nothing to do with it 😄

Now I can put it up for sale with a clear conscience and get my S2A on the road.

Howard

[Mikey]

Good work on updating the thread with the outcome. Glad you found the culprit. It is a good feeling when you finally find the source of problems.

Again, we'll done on coming back to let us all know. Another one to stick in the database that is the grey matter for future reference.

Mikey

[HowardSmall]

No worries. It has been 2.5 months now and the Defender is running like a dream - great acceleration, improved top speed, better fuel economy. Can't believe how nice it is to drive!

Howard

Good work on updating the thread with the outcome. Glad you found the culprit. It is a good feeling when you finally find the source of problems.

Again, we'll done on coming back to let us all know. Another one to stick in the database that is the grey matter for future reference.

Mikey