Thread: !!!FIXED!!!! For Defender Puma rough idling, erratic power and noisy

Hi Everyone,

I can confirm that if you have either a faulty MAF or MAP or both. You will most certainly have poor rough idling and power delivery. Also very noisy.

I had been chasing this issue on a 2.4 Puma for over 6 months. Injectors taken out, tested and flowed, new copper washers, seals, SCV replaced re-calibrated, pilot correction re-done on injectors, sensors cleaned, wiring tested, etc.

You will not get an engine fault, nor will any errors come up on a scan.

The problem is that the MAF and MAP start reporting erratic and false readings, this can be seen on an oscilloscope for each sensor. The ECU then tries to compensate by varying the injectors, etc to match the erratic MAF/MAP readings and this is the noisy rattling at idle and can also force the ECU into limp mode (note you will never see a fault or check engine light like a normal limp mode because the ECU is not programmed to throw a fault on readings alone, it doesn't know what a bad reading is it just takes the MAF and MAP reading and commands the injectors to do what its programmed to do as part of its tune, it needs the MAF or MAP to completely fail and not give any readings before it will throw an error. So instead of throwing an error it will try to adjust scv, injectors to suit and if too many adjustments it will run a safe tune map, albeit intermittently (this is the sluggishness you will feel when driving and poor throttle response). This also presents itself as one day car runs fine, another it's rough, sounding like a bucket of bolts, underpowered, or sometimes it can be on and off in a single drive or day. Might be bad when cold and good when warm, etc, etc.

Changing the MAF and MAP in my case totally removed all and every symptom I was having, and it is now running like a Swiss clock.

Also there are variances in the brand and make of MAF (MAP I only used genuine because they are cheap) however do not skimp on a MAF and I will say that the original ford MAF is very sensitive in that if you later down the track decide to change your airbox and intake piping around it will effect how the Ford sensor feeds info to the ECU.

There are only two sensors I would recommend, they are:
Pierburg (German made) Part number: 7.22184.76.0 can be purchased in Australia through Goss Goss - Home (Part No: AM70M54N) along with all other engine sensors, type your rego in here and it will give you a full list of sensors for your vehicle Goss - Catalogue
Goss sensors can be purchased through any Repco, supercheap, etc.

Or you can buy genuine ford sensor through ford part number 6C1112B579AA
Or Land rover genuine sensor part number MHK501040
The ford and land rover sensors are both identical and very sensitive as mentioned.

How do I know, because I have run all three on an oscilloscope and monitored their results.

I prefer the Pierburg as it is more forgiving to relocation for aftermarket airbox and intake piping.

I will add that you do not need to buy the expensive BAS or GAP tool to calibrate, replace injectors or SCV on the 2.4 Puma (not sure about the 2.2 puma)
Instead a free app can be used on either an iPhone, Android or Windows PC called Forscan. For=Ford, Scan=Scan (All puma's run a Ford Duratorq 2.2 or 2.4 engine and ECU, the forscan diagnostics tool supports the 2.4 i am sure because I have used it but it wont let you flash an upgraded tune or immobiliser disable to the ECU, strictly servicing and maintenance)
Download for Forscan available here Download FORScan

You can buy an ODB adaptor, either

USB: https://www.aliexpress.com/item/4000995546207.html (!!!NOTE!!! this will only work on a Windows Computer)
OR
Bluetooth: https://www.aliexpress.com/item/1005001908469352.html (iPhone or Android)

Hope this helps someone and saves them money.

All the best

3:1 the no fault code on noisy(erratic) signal was a ford engineers solution to the landrover (and Im looking at you td5) tendancy to throw a noisy signal code because a butterfly landed on an badly grounded power pole in india (or any other more significant fluctiation on any part of the electromagnetic spectrum on this or any other planet)