TD5 power/revs fade

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IanMKD

New Member
Posts
3
Location
Midsomer Norton
My Defender has developed an alarming tendency to fail to pick up power particularly from starting. What seems to happen is that when I change gear, having accelerated & therefore picked up revs, is that it won't continue to pick up in a continual increase of revs - it just stays flat. In fact, from starting, I can change from 1st to 2nd & literally get no response, if I depress the accelerator it takes a few moments (5 - 10s) to increase the revs. It's less pronounced once the engine is warm but nevertheless it still happens but to a lesser degree.

Any one help or got ideas what the problem might be?
 
Throttle potentiometer on it's way out? Damn drive-by-wire elecktrickery rubbish ;)
 
Get the fuel pressure checked - it should hold 4 bar all the time the engine is running.If the Storm ECU see's a faulty input from the throttle pot it will most likely just go back to idle.
 
eightinavee said:
Get the fuel pressure checked - it should hold 4 bar all the time the engine is running.If the Storm ECU see's a faulty input from the throttle pot it will most likely just go back to idle.
Click to expand...

I gotta get that gauge stuff for mine ....

CharlesY
 
IanMKD said:
My Defender has developed an alarming tendency to fail to pick up power particularly from starting. What seems to happen is that when I change gear, having accelerated & therefore picked up revs, is that it won't continue to pick up in a continual increase of revs - it just stays flat. In fact, from starting, I can change from 1st to 2nd & literally get no response, if I depress the accelerator it takes a few moments (5 - 10s) to increase the revs. It's less pronounced once the engine is warm but nevertheless it still happens but to a lesser degree.

Any one help or got ideas what the problem might be?
Click to expand...

Does it smoke?

Riggaz
 
hi try blocked fuel filter.
take turbo hose off intake side they have a problem of colapsing under load.

if lots of smoke could be turbo failure
good luck
Jummy
 
try disconnecting the MAF sensor. Mass Air Flow Sensor. it's located after the air box and going to the engine.

I've this strange problem on mine and the dealership told me for 7500USD we can change your injectors and it will fix the problem.

another workshop told me the fuel pump is weak so for 1/10 of what the dealership told me the problem will be solved.

so i decided, since on cold days the landy feels better but not good and on normal days it just takes ages and flooring the gas yields no difference, i decided that maybe it's the in coming air flow.

when MAF sensor fails, lack of power happens as stated in the workshop manual, so i tried it and the car's back to normal. but when i decided to plug the MAF back, it's the same old crappy performance.

so i conclude, which i'm still pondering, either the EGR is choked or the MAF is faulty. when MAF is not connected, the EGR system is also disabled (not sure but that's what the workshop manual says).
 
From the workshop manual.

The MAF sensor is located in the intake system between the air filter housing and the turbocharger. The ECM uses the information generated by the MAF sensor to control exhaust gas recirculation (EGR).

The MAF sensor works on the hot film principal. The MAF sensor has 2 sensing elements contained within a film. One element is controlled at ambient temperature e.g. 25 °C (77 °F) while the other is heated to 200 °C (360 °F) above this temperature e.g. 225 °C (437 °F). As air passes through the MAF sensor the hot film will be cooled. he current required to keep the constant 200 °C (360 °F) difference provides a precise although non-linear signal f the air drawn into the engine. The MAF sensor sends a voltage of between 0 and 5 volts to the ECM, proportional to the mass of the incoming air. This calculation allows the ECM to set the EGR ratio for varying
operating conditions.

Inputs / Outputs
The MAF sensor receives battery voltage (C0149-3) via the ECM on a brown/orange wire. Signal output on a slate/light green wire from the MAF sensor (C0149-2) to the ECM (C0158-11) is a variable voltage proportional to
the air drawn into the engine. The MAF sensor is provided an earth (C0149-1) via the ECM (C0158-20) on a pink/black wire.

The MAF sensor can fail or supply an incorrect signal if one or more of the following occurs:
• Sensor open circuit.
• Short circuit to vehicle supply.
• Short circuit to vehicle earth.
• Contaminated sensor element.
• Damaged sensor element.
• Damaged wiring harness.
• MAF sensor supplies incorrect signal (due to air leak or air inlet restriction).

In the event of a MAF sensor signal failure any of the following symptoms my be observed:
• During driving, engine speed may dip before recovering.
• Difficult starting.
• Engine stalls after starting.
• Delayed throttle response.
• EGR inoperative.
• Reduced engine performance.
• MAF signal out of parameters.

In the event of a MAF sensor failure, the ECM will use a fixed default value from its memory.
 
Hi.

My Defender had this problem. Initially cured by new airlow meter. All was fine for a while , but still has the same fault but on an intermitant basis. Still have the problem from time to time and as Defender is under warranty it keeps going back, having a new turbo fitted tomorrow as dealer thinks this may be faulty with sticking wastegate??
 
ian2988 said:
Hi.

My Defender had this problem. Initially cured by new airlow meter. All was fine for a while , but still has the same fault but on an intermitant basis. Still have the problem from time to time and as Defender is under warranty it keeps going back, having a new turbo fitted tomorrow as dealer thinks this may be faulty with sticking wastegate??
Click to expand...

It could be chap, modern turbos are variable geometry so if the wastegate or the vanes in the turbo stick then it will over boost causing it to go into limp home mode.

Riggaz
 
If all that does not work, take the fuel tank out and remove the fuel pump.
Theres a filter on the base of the pump which tends to get blocked over the years and because its not easy to get to is left 'til there's a problem.
Short cut, you could carefully cut a hole in the floor above the fuel pump, saves taking the tank out.
 
another hint, i've discovered oil in my air intake too. this actually screws up the Manifold Absolute Pressure (MAP) sensor & Inlet Air Temp (IAT) sensors causing loss of power.

you can check by removing the Td5 cover on the engine block, locate the air hose from the intercooler, if there's quite a fair bit of oil, you see it on the hose. this indicates that the engine oil has made it way to the inlet manifold.

usually this is caused by the air intake hose sucking in engine oil from a hose which connects to a valve on the air intake pipe which come out from the air box to feed the turbo. when the valve fails, oil enters the air way and hence gets pushed into the intercooler and then eventually into the inlet manifold.

---------

if you really want to get to the fuel pump, you can just drill out all the riverts on the rear bed and then remove the floor board. it's easier than trying to estimate where the fuel pump is and cutting a hole in the floor board.
 
achuakh said:
try disconnecting the MAF sensor. Mass Air Flow Sensor. it's located after the air box and going to the engine.

I've this strange problem on mine and the dealership told me for 7500USD we can change your injectors and it will fix the problem.

another workshop told me the fuel pump is weak so for 1/10 of what the dealership told me the problem will be solved.

so i decided, since on cold days the landy feels better but not good and on normal days it just takes ages and flooring the gas yields no difference, i decided that maybe it's the in coming air flow.

when MAF sensor fails, lack of power happens as stated in the workshop manual, so i tried it and the car's back to normal. but when i decided to plug the MAF back, it's the same old crappy performance.

so i conclude, which i'm still pondering, either the EGR is choked or the MAF is faulty. when MAF is not connected, the EGR system is also disabled (not sure but that's what the workshop manual says).
Click to expand...

If you take the air mass meter out then it should run dreadfully as the ecu cant decide how much fuel to put into the cylinder

Riggaz
 
achuakh said:
it's running fine now. seriously. i think the default values are better than the wrong values.
Click to expand...
You are right,the default just takes a bit of shine off the top end.Loads of times I have noticed dead airflow meters on TD5 whilst looking for other faults - the owners didnt know anything was amiss.
 
My 2004 90 TD5 is a pain.I have had the new turbo fitted and it goes very well pulling from 1200 revs like a train. When cold i hardly have to touch te accelerator and it flies. However, after a short journey and it gets up to temperature the performance seems to tail off again and i have to press the accelrator further to get the same performnce, and it would seem some turbo lag too.I am thinking that boost pressure may be reducing as the temp rises causing the drop in performance my question is, can the electronics/ECU reduce the amount of boost availale and if so can i make it stop!
 
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