Thread: '04 Defender - Occasional lack of power

I know exactly what you are talking about. I have an 03 Defender single cab. It feels like the air flow meter is not functioning correctly but I have swapped a new one over and it still performs the same. The problem is intermittent as you have described. I haven't been able to find out what is wrong either and when checked it also shows no computer faults. I can't help but would love an answer also.

Originally Posted by Mellow Yellow

I haven't seen a thread on this particular problem but if anyone knows of one please point me at it.

Every so often with a standing start I experience a lack of power which lasts anywhere from 5 to 10 seconds. Peril will move off but not accelerate until suddenly it regains power and gets on its way with a sudden burst of acceleration (a bit like the turbo lag in my diesel D2 a few years back). It can happen whether the engine is cold, warm or hot.

I usually get away from being stationary with 1000 to 1200 rpm but when this problem arises and I use higher revs (eg 1600-1800 rpm) the same thing still happens, i.e. no acceleration until back to normal with a sudden surge. Throttle position doesn't affect this behaviour - keeping the throttle constant or flooring it after getting rolling still sees this lack of power/acceleration.

I can have this happen several days in a row but on the other hand I can have many weeks between the times it happens. It can happen on the flat or on a hill. It can happen lightly loaded or heavily loaded (eg towing). Don't think its got anything to do with ambient temperature. My fuel tanks are clean and I have no reason to suspect dirty fuel.

There are no faults showing in the ECU (via a nancom). The electronic throttle plug/connection has been checked and appears OK. It's been re-mapped by Tombie2 but I don't think this has anything to do with it (best mod I've done to Peril) and its "EGR-less".

Has anyone experienced (hopefully solved) this problem?

Might be a good idea to check the intercooler hoses. These can internally delaminate and cause the sort of problems you are describing.

Cheers,

Lionel

Thanks for those quick replies Stealth and Lionel.

It helps to know that someone else is experiencing the same problem as it means the mods I've made to Peril probably have nothing to do with causing it. It's also interesting that we have 110's of about the same age.

I'll check the intercooler hoses in the next couple of days. When I bought Peril last year I replaced all the coolant hoses (the to be sure, to be sure principle) but it didn't even occur to me that the intercooler hoses might give me problems.

Originally Posted by Mellow Yellow

Thanks for those quick replies Stealth and Lionel.

It helps to know that someone else is experiencing the same problem as it means the mods I've made to Peril probably have nothing to do with causing it. It's also interesting that we have 110's of about the same age.

I'll check the intercooler hoses in the next couple of days. When I bought Peril last year I replaced all the coolant hoses (the to be sure, to be sure principle) but it didn't even occur to me that the intercooler hoses might give me problems.

I has a misfire problem early on which turned out to be the throttle pedal. It drove me nuts for a couple of weeks and then suddenly went into limp mode. At that point it left a fault code in the ECU, which made diagnosis easy. (all under warranty fortunately!) You have checked this, so maybe it is not so likely here.

There is also the "oil in the injector harness" problem, which should be checked out, and also the turbo waste-gate linkage, where sticking can cause occasional over-boost. I remember being told by a mechanic at MLR that this will cause the ECU to shut the fuel delivery down when this happens.

I am sure someone else on the forum with greater knowledge than myself can give more info.

Cheers,

Lionel

Good thoughts. Shouldn't be an "oil in harness" problem as I replaced the harness late last year. A sticking waste-gate is certainly worth checking.

Thanks.

Originally Posted by Mellow Yellow

Good thoughts. Shouldn't be an "oil in harness" problem as I replaced the harness late last year. A sticking waste-gate is certainly worth checking.

I experienced similar symptons on my previous 110 Td5 - it was traced to a faulty crank position sensor.

Sometimes just cleaning it works, which I did and the problem went away for a few weeks. The next time it returned I had it replaced. It's not an expensive part and your indie LR mechanic should be able to do it in 15min.

Have taken up Lionel and Nak's suggestions as follows.

The intercooler hoses were not delaminating but were a bit on the soft side. Peril's done 150,000Km and I intend to do at least another 100,000Km so I figured I'd change them just to eliminate any possibility of problems with them in the future. So I put in a set of silicon hoses (the to be sure, to be sure principle).

The waste-gate linkage is OK.

Have a crank position sensor winging its way to me in the post now. As soon as I get it I'll put it in. Of course, due to the intermittent nature of this problem, it's possible that I won't know for sure for a couple of months whether the crank position sensor was faulty or not.

Hopefully my next post on this thread will be in three months time reporting problem solved. Thanks for your help guys.

Since I replaced the crank position sensor I've had two lesser experiences of the "no get and go" problem. Not as bad as previously so maybe the crank case sensor has had something to do with it.

However, I recently stumbled across this on the UK site www.TD5Alive.com which pointed the finger at the Mass Air Flow sensor :-
"Faulty air flow meters can cause a number of running faults. They only last for xxxx number of running hours, and can then give output values which are usually lower than they should be, which will make the car feel lethargic. It's common for later model TD5's to feel extremely flat for the first 30 seconds of running, before coming to life, when the ECU switches to it's internal default values."

The MAF sensor had been checked a number of months ago and was OK but when I got hold of my own Nanocom Evo just recently (courtesy Paul38a) and checked it, it was stuck on a very low reading. Obviously very much dead. Maybe MAF's don't die suddenly but "slowly fade away" or become intermittent.

So a new MAF has gone in and I'll have to wait and see if it solves the problem.