Td5 with altitude sickness

[jbe]

​My Defender 110 Td5 has developed some form of altitude sickness. The car runs perfectly well day in and out on sea level and on altitudes up to around 700m. If I drive at around 1000m altitude, the engine runs just fine and accelerates perfectly normal until it hits 2500rpm.Then it starts jerking/stuttering aggressively, dropping power and getting it back at a frequency of one per second. It is virtually impossible to accelerate beyond the 2500rpm in that situation.

The turbo boost gauge doesn't show any fluctuation or movement up or down.

All, I can remember having done around the engine lately, was to the the intake ducts apart and re fit & seal them with MAF friendly sealant. I also cleaned the MAF sensor twice, bit this didn't make a difference.

Also, there are no fault codes logged.

Cheers
Joachim

[djam1]

Have you checked for oil at the ECU due to the injector loom??

[jbe]

Yes, I have, but will check again.

[harro]

Input for altitude come from the AAP sensor on the airbox lid.
Disconnect it and it defaults to 100 kpa (sea level).

See how that goes, it will tell you if the sensor is faulty or not.
Hopefully just a clean as they are quite expensive.

Paul.

[gusthedog]

Do td5s in defers hit overboost? Sounds like what happens to my d2 - a half turn back on waste gate solved it.

[djam1]

What is the boost pressure?

[harro]

Do td5s in defers hit overboost? Sounds like what happens to my d2 - a half turn back on waste gate solved it.

Yes, at same point as Disco td5's.

[jbe]

What is the boost pressure?
I think around the 16PSI mark. I have to admit, I was more concentrating on fluctuation than actual readings.

[jbe]

What baffles me is that I had no issues for most of the two years, I've owned this car. It'd been happening for the last two and a bit months and is fairly consistent.

[jbe]

Input for altitude come from the AAP sensor on the airbox lid.
Disconnect it and it defaults to 100 kpa (sea level).

See how that goes, it will tell you if the sensor is faulty or not.
Hopefully just a clean as they are quite expensive.

Paul.
What is the best way to clean the sensor?

[harro]

What is the best way to clean the sensor?

I use 'contact cleaner' in a pressure pack.

[discorevy]

also try running with the maf disconnected, they can be overcleaned especially if something other than dedicated maf cleaner was used, what year is the deefer?

[jbe]

also try running with the maf disconnected, they can be overcleaned especially if something other than dedicated maf cleaner was used, what year is the deefer?
It’s a 2005 model. The MAF sensor is about a year old and got only cleaned with MAF cleaner.

[discorevy]

ok , if the maf is vdo it should be ok unless you've increased boost too much, try disconnecting it and go for a run , you'll have a delayed throttle at first but will be ok after that so don't pull out in front of traffic till after the first delay, this is just to diagnose .

[jbe]

ok , if the maf is vdo it should be ok unless you've increased boost too much, try disconnecting it and go for a run , you'll have a delayed throttle at first but will be ok after that so don't pull out in front of traffic till after the first delay, this is just to diagnose .

The MAF is DPL to suit the engine modifications and tune. I forgot to connect it last time I cleaned it and was wondering why the engine was running rough and had a delayed turbo response [bigwhistle].

[sierrafery]

Input for altitude come from the AAP sensor on the airbox lid.
Disconnect it and it defaults to 100 kpa (sea level).

See how that goes, it will tell you if the sensor is faulty or not.
Hopefully just a clean as they are quite expensive.

Paul.
+1 for that^^^

[jbe]

Thanks everyone for all the input.
I cleaned the connectors with contact cleaner and the engine runs just fine here in Sydney.
Today, I plugged the Nanocom in and I got he following engine fault which I haven't seen before:
(3,7) Air Flow Circuit Logged High

I couldn't find any clear definition of this fault on the web. Can anyone explain this fault reading?

Cheers
Joachim

[sierrafery]

The MAF reading is higher than expected for the driver demand and the delivered boost, could be due to faulty MAF or some boost leak

[AllTerr]

Sounds to me like a MAF fault...

[OffTrack]

Thanks everyone for all the input.
I cleaned the connectors with contact cleaner and the engine runs just fine here in Sydney.
Today, I plugged the Nanocom in and I got he following engine fault which I haven't seen before:
(3,7) Air Flow Circuit Logged High

I couldn't find any clear definition of this fault on the web. Can anyone explain this fault reading?

Cheers
Joachim

What the fault means is that the measured voltage for the Airflow Circuit - the MAF - has exceeded the maximum voltage threshold set by the engine map.
That threshold is set to 4950mV for the MAF. If the fault was present when you checked the codes you would have also got a 5,7 Air Flow Circuit Current in addition to the 3,7.

There are a few potential causes - an intermittent fault in the wiring harness, a MAF issue causing over-read and excessive voltage output, or a boost leak somewhere between the turbo and MAP sensor.

[jbe]

I'm staring to think that it could be an intermittent electrical issue. I cleaned the MAF sensor (again) and the connector as well. I also cleared the ECU fault and then drove it like I stole it for about 40 minutes. The engine flawlessly revved up to 3000rpm and didn't miss a beat and most importantly, the ECU didn't log any fault. I'll be off across the Blue Mountains later this week and see how I go at altitude.

[sierrafery]

If you have nanocom, insertb SD card in it and record inputs fuelling from a journey and if the symptom occurs it will be visible on that or if all the sensor readings are OK it means it's fuel supply issue cos that's not covered by diagnostic

[jbe]

I played with the Nanocom and was able to log data to a SD card. I'd be interested in what the experts think. It looks like a MAF problem to me as the airflow drops to 0 on my uphill runs at high rpm.

From what I can see, I don't have an overboost issue.

Also, there is absolutely no oil in the wiring loom (checked at the engine and at the ECU end).

Excel spreadsheet contains some of the data.

Cheers
Joachim

[sierrafery]

Can be two things, the MAF is reading higher than the reality is or there's a slight boost leak between the turbo and inlet.... do you have any kind of tuning?

[jbe]

Can be two things, the MAF is reading higher than the reality is or there's a slight boost leak between the turbo and inlet.... do you have any kind of tuning?

VGT from BAS, Alisport intercooler, ECU re-remapped by DPL. The MAF is non standard to suit the setup; it is part of the BAS kit as I understand. This setup has not been changed off lately. One of my turbo hoses cracked about two months ago. So, I replaced both with silicone hoses. I had to change the clamps to hd turbo clamps to keep them from slipping. I'll check again.

And btw: I had another (3,7) Air Flow Circuit Logged High error logged.

Cheers

[sierrafery]

that air flow high is normal cos that's what happens in the dala log too.... are you sure you are not speaking about the MAP sensor when you say "The MAF is non standard to suit the setup;"? cos that's what they used to do but beside that you need a AFR modification in the fuel map as the MAF to go up to 800+ without cutting out... according to that log when the MAF cuts out(above 650) the MAP is only 205 and that means 1.1 bar boost which is low for that high suction....it seems that your vehicle is supertuned bot not completely or as i said the MAF sensor reads higher than normal or there's a boost leak...unplug the MAF and drive it so untill you fix it

[jbe]

that air flow high is normal cos that's what happens in the dala log too.... are you sure you are not speaking about the MAP sensor when you say "The MAF is non standard to suit the setup;"? cos that's what they used to do but beside that you need a AFR modification in the fuel map as the MAF to go up to 800+ without cutting out... according to that log when the MAF cuts out(above 650) the MAP is only 205 and that means 1.1 bar boost which is low for that high suction....it seems that your vehicle is supertuned bot not completely or as i said the MAF sensor reads higher than normal or there's a boost leak...unplug the MAF and drive it so untill you fix it

Don't know about the MAP, but here is my setup:


- BAS Td5 VGT hybrid and offroad turbo
- Allisport intercooler
- Td5 turbo boost box (alive??)
- modified MAF (that's what my invoice said when I got it replaced) ​
TD5 Upgraded Air Flow Meter | PERFORMANCE | Davis Performance (https://davisperformance.com.au/td5-upgraded-air-flow-meter.html)


- cleaned out airbox to improve airflow
- 3 inch exhaust

[sierrafery]

- Td5 turbo boost box (alive??):censored::oops2:
- modified MAF (that's what my invoice said when I got it replaced) ​
TD5 Upgraded Air Flow Meter | PERFORMANCE | Davis Performance (https://davisperformance.com.au/td5-upgraded-air-flow-meter.html)


as long as that highlighted thing is present i have nothing more to say just that FROM MY POINT OF VIEW it's a SHAME and as long as the MAF was ''uprated'' it should not have cut out at 680 but stay fit up to 850.... i hope that @Offtrack will see this to explain better

[jbe]

Thanks for all the responses.
I'll try baby steps now:

- check turbo hoses again and make sure they are 100% properly clamped

- another 300km round trip to get to 1000m altitude and do the following tests:

​
try to log data on nanocom


[*=1]one altitude run with problem present
[*=1]one altitude run without AAP connected
[*=1]one altitude run with pre-airbox intake plumbing removed
[*=1]clean AAP at altitude and try again




Happy to look into more suggestions

[sierrafery]

​
try to log data on nanocom


[*=1]one altitude run with problem present
[*=1]one altitude run without AAP connected
[*=1]one altitude run with pre-airbox intake plumbing removed
[*=1]clean AAP at altitude and try again




Happy to look into more suggestions
why would you save a data log with AAP unplugged? just to see the default mode with reduced boost? ... your problem according to the data log is that the ECU cuts fuelling due to high MAF input which is normal as long as the sucction is too high due to a sh*t tuning...cos IMO any tuning which involves a boost box to alter the MAP reading is **** while stating that the MAF is "uprated" but it reads up to 680 max and cuts out is a lie IMO.

[jbe]

why would you save a data log with AAP unplugged? just to see the default mode with reduced boost? ... your problem according to the data log is that the ECU cuts fuelling due to high MAF input which is normal as long as the sucction is too high due to a sh*t tuning...cos IMO any tuning which involves a boost box to alter the MAP reading is **** while stating that the MAF is "uprated" but it reads up to 680 max and cuts out is a lie IMO.

I bought the truck with this set up; wouldn't be my choice if I had one.

- driving with AAP unplugged at altitude will proof or eliminate if this is the culprit for my initial problem
- as I said, the engine runs fine anywhere below 850m above sea level
- the seller of the MAF told me that he had a high failure rate with this modified MAF. However, I find it weird that it cuts out at 680 just like a standard one.

So, what's the alternative to using the boost box??

[sierrafery]

So, what's the alternative to using the boost box??
A proffesional and correct remap with uprated MAP sensor and addapted AFR not an ugly bodge with boost box like now IMO

[jbe]

Looks like it is the AAP. I did another test run at altitude after I cleaned all sensors for the fourth time and checked vacuum & turbo hoses over again. Had the same problem, although a bit more subtle. When I disconnected the AAP, the engine ran just fine. Thanks everyone for their input [bigsmile1].

[sierrafery]

The AAP reading looked well in that data log, by unplugging it the ECU goes to a default of reduced boost to 1 bar and at that boost the sucction is lower so the MAF readinng doesnt exceed 680 to cut out, make a test with MAF unplugged too and IMO it will run OK as well, i'm affraid that you'll pay for an expensive AAP in vain