Strange rough when reaching idle

Hello,

I just got my first Defender TD5 hcpu. have been driving a series 3 109 for the past 20 years. I found myself a 2002 with 220000km on it, all in very nice shape and got it for a decent price. One thing I've been noticing is that whe I start it or come off throttle to idle. It will idle very rough. Usually picking up sooner or later to a normal idle. But then again if i blip the throttle or come off it into stop lights or so I am there again, waiting for the idle to even out. I cleaned all the sensors, did not find any oil in the loom sensor. No difference. Then while running i disconnected the AAP sensor attched to the air filter box and the idle evened out immediately. Now with AAP disconnected it will rough idle for 3-4 seconds and then even out and the rough idle is not even as bad as with AAP connected. Tried with another AAP sensor from a disco but no difference. Where should I start looking for sollution here? I know the series 3 stuff very well and 200Tdi as I run one in my series but the TD5 is all new to me. Love the car already though, except this rough idle feature I cannot sort out.

northernbobber said:

Hello,

I just got my first Defender TD5 hcpu. have been driving a series 3 109 for the past 20 years. I found myself a 2002 with 220000km on it, all in very nice shape and got it for a decent price. One thing I've been noticing is that whe I start it or come off throttle to idle. It will idle very rough. Usually picking up sooner or later to a normal idle. But then again if i blip the throttle or come off it into stop lights or so I am there again, waiting for the idle to even out. I cleaned all the sensors, did not find any oil in the loom sensor. No difference. Then while running i disconnected the AAP sensor attched to the air filter box and the idle evened out immediately. Now with AAP disconnected it will rough idle for 3-4 seconds and then even out and the rough idle is not even as bad as with AAP connected. Tried with another AAP sensor from a disco but no difference. Where should I start looking for sollution here? I know the series 3 stuff very well and 200Tdi as I run one in my series but the TD5 is all new to me. Love the car already though, except this rough idle feature I cannot sort out.

Click to expand...

Same problem here, it developed after fitting new injectors and glow plugs

Loads of stuff on here about it with lots of replacement parts advice etc

I Replaced ( my engine is like triggers broom now)

* cheap and easy

Fuel pump
Injector seals
Fuel filter head*
Fuel no return valve in filter head*
Injectors
Crank Position Sensor
Ambient Temp Sensor*
MAF Sensor
MAP Sensor ( try cleaning that its easy and on the inlet manifold)*
Turbo Actuator*
Valve cover breather valve ( mushroom thing on piper near turbo)*

Ended up getting a new fuel map on ECU which fixed it in the end, must have been a software glich

its a bit of a rabbit hole mate, check clutch switch, EGR is working properly etc.

Fuel pressure relief valve the list goes on.....

Thanks man, really apreciate it. Previous owner has had the injector work done on it. So maybe it has avvured at that time. So you don't think the AAP sensor in itself has anything to do with it? Should I begin by gettng a new ECU map? how do i check that the EGR is working properly?

Also why do you think removing the AAP sensor made the issue slightly better?

MAP sensor can get gunked up due to muck from exhaust gases via EGR, oil and deposits etc, give it a clean.
You be surprised how dirty and what a difference it can make, its a 5 min job.

Read here:

https://www.landyzone.co.uk/land-rover/removing-and-cleaning-a-td5-map-sensor.198286/

Try the cheap things first, no harm in replacing them anyway etc.
You don't need a re-map necessarily, just make sure the fuel map is the correct one for the vehicle and is the latest version, but as I said try the cheap and simple things first.
The EGR is simple to remove and clean, hers some horror show pics of clogged egr's dont have nightmares!
My one was nearly this bad but was a bit gunked up, its a doddle to remove and clean with brake parts cleaner, dont bother squirting stuff in there (EGR cleaners) you can buy waste of money etc. take it off and do a proper job.

PS: AAP/ATS (Ambient Air pressure / Ambient Air temperature Sensor = Same thing:

Both terms are used just to confuse us!

https://workshop-manuals.com/landro...r_ambient_air_pressure_and_temperature_(aap)/

yeah, I cleaned the MAP sensor. Now I ordered an EGR bypass kit to get of the egr all together. also a new aap sensor. I'll see what these does and then I have someone I know who seem to have a nanocom reader so i can see for fault codes. Also how did you change the map to make yours work?

edited a little since you beat me in speed

So my ECU was not the original one.
My ECU was the correct ECU but from a vehicle a year older (not that it made any difference until I had the problem!)
Anyway I had the ECU and the software checked.
Hardware: I wanted to be sure the ECU itself was functioning correctly and sending out correct voltages and signals as it should.
Software: I had the software updated to the latest version, with the correct fuel map for the TD5 15P engine.
Alive Tuning did this for me, I sent the ECU to them.

If the previous owner had some injector work done, do you know if they coded the new injectors correctly to the ECU?
You really need to make sure that this was done correctly, NANOCOM is ok but can be a bit temperamental especially when messing with ECU settings.
You need to have a really good, clean power supply and not just a good battery etc.

Do you know the serial number of your ECU?
And if you have the rocker cover off note the injector numbers and type (green or black top), you could change your injector loom at same time etc.
I assume you have checked for oil on the red connector on the ECU? Oil tracks back along wires form injector loom, causes a heap of hard to indetify troubles. Again a simple and cheap job to check and to replace injector loom, pull off red plug on ecu and check for oil, if you find some clean it very well with brake cleaner and change injector loom under rocker cover,

thanks, yeah I checked for oil in the red connector, nothing really. But I will tae the ECU off to mak sure there is nothing inside. At the same time I check the serial of it. I don't knwow exactly what they have done ECU wise after the injector work. But i ordered also the harness so I can replace it when I go and check the injector numbers. I'll get back when I get to that point. I might try as you did first to just update the latest default mab for my ride and see where that takes me. next I go under the rocker cover and do the job there if nothing changes on the update.

check the mushroom valve thing, should really be considered a service item and changed when you do full oil and x2 oil filters etc its cheap etc

Thanks, yeah I ordered one of those too. I am going to replace all fluids and filters and so on as the items arrive.

i feel your pain mate drove it me mad.

Check live data from diagnostics to see if all sensors are in correct range.
In the meantime unplug the maf sensor and see if it’s any better

I have tried unpluggin gthe MAF, but it doesn't seem to do much. Isn't the MAF affecting the turbo and the higher rpm performance, mine pulls strong and is not lazy at all, my problem is with Idle. And now it has also developped an occational hard starting issue, I have now two times had to spin the starter for a while to start it. It starts to start but needs to spin some time with the starter to pick up. Feels like air in fuel system a little, but I dont think so. changed the fuel filter also. What do you guys think about trying to reset ecu by removing battery and connecting the cables together to drain the voltage from the system as someone described somewhere?

Ok, I ordered also a nanocom td5 defender kit. The price wasn't that bad since the landy shops here take 90e/hour to do anything on the vehicle, It will pay itself back pretty soon. Also upload maps and it's gonna save me some bucks I think in the long run whn I can pinpoint the issues better. I'll get back toyou guys when I've received it and can give more information.

Did some soulsearching today. I found out that at least the valve on the fuel filter mount was shot, going both ways. Replaced that and I think hard start issue is gone. The rough idle still remains. Not as bad though but still for 5 seconds when coming into idle. And constantly until engine is warm. I got my nanocom and it doesn't give any fault codes. I am still waiting for my egr blanking kit to see if that has an effect. It seems like my cylinders are compensating from -3 to 3 at maximum. Idle -1 to 1. So I don't know. I am interested in flashing the ECU with the default map to see if that corrects something. Trying now to understand flashing ecu and where to download the default map for my vehicle.

Be careful! nanocoms can brick your ecu.

make sure you have a constant supply voltage to the battery, any deviation in battery voltage causes problems.

KISSMYAURA said:

Be careful! nanocoms can brick your ecu.

make sure you have a constant supply voltage to the battery, any deviation in battery voltage causes problems.

Click to expand...

Make sure you have latest software version for your engine, and then the correct fuel map for your engine type (10P, 15P etc)

Thanks yeah. I just cant find where to pick those files up. The nanocom genesis does not cover Td5, they claim in the forum that those should be found elsewhere but I have no idea where. I might leave it until ive got rid of EGR and so on in case that is the cause of the problem.