Thread: PUMA 2.4 Rough / Lumpy Idle only when cold - SCV, Injectors, EGR, MAF or MAPT

Originally Posted by spudfan

The VCV (Volume control valve) could be at fault.

I am fairly certain it is the VCV (SCV). I have had it replaced with Denso part no. 294200-0360 which is supposed to be compatible with my fuel pump (294000-0951) but it is a different part number than the Denso replacement part for the VCV (294009-0260).

As far as I can tell the recommended replacement part (294009-0260) costs around $480 (or at least that was what I was quoted over the phone today) and the part no that was used when I had it replaced (

294200-0360

) costs around $190. They are supposed to be interchangeable and have the same specs (from what I can find) so why the price difference? BTW I am not 100% convinced that the $480 quote was for a

294009-0260

. I suspect that if I ordered it I would get a

294200-0360

.

The Denso site is a complete disaster so I can't find any reference to the part numbers unless it is on another 3rd party vendors site so I am relying on them being right.

These guys seem like they know what they are talking about:
Land Rover Defender 2.4 Td4 Reconditioned DENSO Diesel Fuel Pump - 294000-095#, Specialist Diesel Injection Services Ltd.
At least all their references make sense.

Also these guys say the SCV will suit the pump I have
Suction Control Valve to suit Nissan Navara & Pathfinder / Mitsubishi Triton & Pajero A6860-VM09A / 294200-0360 - Baileys Diesel Group

No clear answer in sight!!!!!

Well after all that look what I just found:
https://bellautoservices.co.uk/store...-vapour-valve/

Pete is a legend. I know where I will be buying it from - might get an intercooler thrown in as well

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

Originally Posted by titus

Hi Everyone,

I thought I would share my current situation with my beloved Defender and see if any of the wizards on the forum have any pointers of what to do next. If you can't be bothered reading the saga below then these are the main points:

1) Very rough / Lumpy idle when first starts. Then when up to temp runs smooth
2) Initially changed fuel filter and ran through many tanks of injector cleaner / biocide / cylinder head cleaner
3) Found a slight leak (not even sure it was there but found some blow back under rocker cover) on one injector washer so replaced all washers
4) Changed SCV valve - no pump relearn as I don't have anything to do that and the stealers want to charge me $300 to do it. I would really give my money to Pete at BAS
5) Changed all glow plugs
6) Compression test - 360 across all cylinders
6) Cheap OBDII scanner gives me no fault codes and show that when coolant temp hits 30 degrees the EGR shuts off and 95% of the roughness goes away but a little bit is still there until the coolant hits ~ 60 degress
7) Not convinced it is injectors given the above as wouldn't the injectors exhibit rough idle almost all the time?

Last winter Fergie (my 2010 - 110) started sounding a bit grumbly when I first started her up on cold frosty mornings (I always run alpine mix when it is available). Not too bad but enough for me to think I need to check the fuel filter etc. and run through some injector cleaner. Initially I replace the fuel filter and added 100ml of Moreys injector cleaner to each tank and things slightly improved and I thought all was ok. A few months later my Mum (bless her) thought she would drive Fergie down the paddock but she stalled her about 400 times in a row. Apparently the anti stall tech doesn't work when you try to take off in 5th. Anyway, I was walking up from the paddock and all I could here was Mum turning the ignition like a mad thing and Fergie refusing to start. I jumped in and I tried to start her and she wouldn't budge - massive hissy fit. It was like she was flooded. No ignition in the engine at all. I let her sit and glowed her a few times and she fired up but ran as rough as guts. Really bad. After a few minutes she settled down but didn't sound right. I took her home, gave her a cuddle and tucked her in for the night. The next morning she still sounded rough when first started so that night I disconnected the battery overnight to try and reset the ECU (I don't even know if this works) as the only thing I could think of was that Mum's constant turning over and stalling caused the ECU to have a heart attack and try to correct a problem that wasn't there. Anyway, this might have had made some difference but I am not 100% sure now as every time I listen tot he motor I hear knocks and stutters that weren't there before.
I took her in to the local mechanic (a mate of mine) and he said injectors. I wasn't 100% convinced, especially at the $3k price tag to replace them so I trolled the forums and found some similar issues and took their advice. I bought a cheap OBDII scanner to look for fault codes and found none. I haven't tried to force a code yet but will disconnect the EGR today and see if the scanner picks it up. I then took her to a diesel specialist (and he is good I have used him several times before - Pete from Wodonga diesel - legend) and we decided to change the SCV valve and replace the washers on the injectors. This seemed to make Fergie run smoother but didn't fix the cold start / rough idle. I then took her back to Pete and we put new glow plugs in and did a compression test (360 across all cylinders). Now running rougher than ever but still only when cold. When she gets up to 30 degrees she almost immediately losses 95% of the roughness (but not all) and the EGR drops to 0% commanded open.

I need help now as I am at a loss and really don't think the injectors is the problem and don't want to spend $3k to find out.

Thanks a million for taking the time to read this. I will post any updates when I have them.