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

[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.

[DiscoMick]

So it improves once the EGR opens? Only guessing but could the EGR be faulty?

[justinc]

Please don't tell me it isn't only 340psi??
I'm going to suggest that there lies your first problem. 2.4 tdci should be 390 to 410psi.....


Jc

[titus]

So it improves once the EGR opens? Only guessing but could the EGR be faulty?

I presume the EGR is closed as I am going off the reading from the OBD which says the EGR is 0% commanded open - which I read as 100% closed. And I presume that means that no exhaust gas is recycled at this point. I was thinking the EGR as well. Was going to grab a BAS RPC to disable the EGR

[titus]

Please don't tell me it isn't only 340psi??
I'm going to suggest that there lies your first problem. 2.4 tdci should be 390 to 410psi.....


Jc

I just chased down the comp test invoice and it is 360 psi across all not 340 so sorry about that. Pete did think it was a bit low but it is even across all cylinders so thought that should be ok. Also the engine blows almost no smoke at all and I haven't noticed any significant power loss. Just out of curiosity, what could cause a uniform compression drop across all cylinders?

[justinc]

Unlikely to have a set of 4 bent conrods from hydraulicing unburnt fuel after repeated stalling/ starting... so im at a loss to explain this especially since all were similarly low. However i think that focussing the investigation on what systems are at play during the stalling/stop/start scenarios would be a good start. The tdci system isnt simple and really requires a knowledgeable person with the correct diagnostic tool to go over it.

Jc

[titus]

Thanks JC, I know I am clutching at straws and I really appreciate your input. I think the next step is trying to disable the EGR when it is fully closed and see if this fixes the issue. I am not convinced but I am equally not convinced it is the injectors.

BTW The issue with my mum repeatedly stalling may not have anything to do with this but may have just magnified an issue that was already there. Good thing is I am learning a lot about CRD engines Just hoping it wont cost me too much for the lessons

[Robmacca]

Hmmm.. I'm wanting to go to one of these 2.4ltr Tdic Pumas in the near future, kinda hope this is one of those isolated/rare problems ??

[titus]

Hmmm.. I'm wanting to go to one of these 2.4ltr Tdic Pumas in the near future, kinda hope this is one of those isolated/rare problems ??

Mine has been great up until this point - 160k and lots of towing / farm / 4wd use. Only real issues I have had (aside from wear and tear) have been with the freakin immobiliser at servos etc!!!!

[Robmacca]

Mine has been great up until this point - 160k and lots of towing / farm / 4wd use. Only real issues I have had (aside from wear and tear) have been with the freakin immobiliser at servos etc!!!!

The one I've been looking at has 170k on the clock..... What's the issue with the immobilisers? Can this be disabled?