DPF and EGR 'issues' with performance tuning

**andrew hastie** · 9th December 2009, 20:15

HI, I'm new to this so... i have a Signum 150 cdti auto and recently fitted a performance ignition module from a reputable company. They assured me it is set up to take into account diesel particulate filters. Hmmm. Initially i was very impressed, 180 ish BHP and average MPG of 59. The car has only done 22K when i got it and 29k now. Over the last few days i have had the 'yellow spanner' and the usual VX dealer tales of woe invloving £880 replacement filters etc. they are currently trying a replacement EGR as they think that might be fooling their diagnostic computer into thinking the DPF is ******ed (lets hope so as £170 is better than £880). There is lots of advice on internet about DPF and EGR issues but none relating to performance chipping in the mix. Oh, and the boot is stuck shut, the central locking unlocks it with a loud clunk but it will only open a few mill and needs thumped closed everytime you have unlocked the doors. Obviously it needs lubed but any ideas on how to get it open in the first place? As I say, I'm new to this but would really appreciate any suggestions as reading this forum, there is some very clued up VX folk.

**vecgsiboy** · 9th December 2009, 20:33

With an increase in power comes an increase in more fuel used and so more "soot"from the fuel are "not so fuel"burned,generally speaking 9 times out of 10 no problems,and a good hard run can clean the system out for you,try giving it a hard run sometimes to keep things from sticking.As regards you boot sorry on that one

Hope this short explanation helps.....

**ANDY W** · 9th December 2009, 20:41

I have a Regal EDS Remap which is designed with the DPF in mind as the DPF now kicks in every 1000 miles instead of the standard VX time. Anyway back in the summer I had problems which put the management light on, the first time I was told that the DPF needed a manual regen which was done and the fault was sorted I thought. The light came on again so I took it back to the garage where he said that the DPF was blacked again and another manual regen was needed which he then tried to do. The DPF woulnt regen and I was told that a new DPF was needed at around £1000 as at the time I thought that my manufacters warranty was void ( another story ). I was not to happy about this so I went to Grassmere in Crewe where they checked the car over and come back with the EGR was blocked, and not working and a new moddified version was being fitted under warranty (result). Once fitted they then did a manual DPF regen which was succesful and still is good. The car seemed loads more responsive lower down the rev range with pickup from standstill loads better in fact I can wheelspin from standstill and my car is a Automatic too.
So I hope a new EGR and a manual static DPF regen will sort your problems out like it did for me

**andrew hastie** · 9th December 2009, 20:55

cheers mate, I have been told that the dealer can only do a forced regen once. My problem is that due to the software,?? the car will not do a regen even at the dealer. Maybe a software update is needed? what i Am not too sure about is why the car has not done the automatic one. I have had the egr stripped and cleaned and mechanically it's fine but vx still insist it's faulty so can only assume it's the solenoid side of it. I have had the tech diagnostic machine on it saying 88% saturated but then I read that the automatic regen does not occur until 90 odd %.

**ANDY W** · 9th December 2009, 20:59

Thats what I mean matey as my car would not do a regen the 2nd time because the EGR was bust but once that was replaced everything was sorted

**snapsnap** · 10th December 2009, 10:12

Originally Posted by andrew hastie

Obviously it needs lubed but any ideas on how to get it open in the first place?

There is an 'emergency' release on the inside of the boot; look for a rubber/plastic bung on the carpetered area around the vicinity of the lock. You'll need a torch!

**diesel dog** · 10th December 2009, 19:15

Tuning boxes are sometimes marketed as being DPF friendly. I can't think what the difference between one of those and the non-DPF ones could be? I wish someone could tell us.

At any rate, all that soot has to go somewhere, and the harder you drive it, the sootier it will get. If you've fitted a tuning box then 'Italian tune-ups' do not work on EGRs or DPFs, if anything it makes them worse.

When you accelerate or floor the throttle the EGR valve shuts, which then effectively creates a 'dead-leg' of the EGR passage. What this then means is, that with a box on, the soot from the exhaust not only fills up the DPF in double quick time, but also the exhaust side of the EGR valve passage gets choked in soot, and until the EGR valve opens again it has nowhere to go!

You can ensure that you have the latest software update for the regen, but that doesn't take into account that you have a box fitted on, which, if it is even slightly over-fuelling, will fill the DPF in no time.