very low power pre 2000rm after DPF unblocked

scott1977 · October 12, 2016

Hi guys, I had the dreaded DPF blockage, but since it was unblocked, the power at low revs is awful, its almost like trying to pull away in a higher gear than I should.

I am going to clean the EGR tomorrow, as that's the first port of call I suppose. Anyone else got any ideas on what could be the problem?

It was fine before the car went into limp mode, so I am assuming that it is something related to the blockage? Could the soot have backed up at all or something?

thanks in advance

Scott

Shahpor · October 12, 2016

Hello.

If it also boosts a little later than it should, then it sounds like classic EGR blockage.

They both tend to go hand in hand, so if your DPF was blocked, it is a good bet that your EGR valve is also in bad shape.

I cleaned mine a while back, and then after 5000 mainly motorway miles, it was full of soot again.

The EGR valves really do need regular cleaning to keep on top of the situation, so thankfully it is a relatively easy job to do.

Did you read the fault codes when it went into limp home mode?

scott1977 · October 13, 2016

thanks for the reply mate, yeah, I clean it regularly, so last time was about 4 months ago, but it the DPF got completely blocked as it did, it probably backed up?

The only fault code that was showing was the DPF blockage. Any other ideas if it doesn't work?

Shahpor · October 14, 2016

Both getting backed up is the theory. It might not be the case, but it is definitely the first place to start.

Did you clean it today?

If is not that, then it can be tricky. The most obvious path is a turbo related fault, but these usual have some other signs as well, such as noise and smoke. Might be worth a look; Take the inlet pipe off the front of the turbo and have a look at the blades, check the shaft for play and make sure the waste gate isn't stuck. That sort of thing.

scott1977 · October 14, 2016

Cleaned the EGR and it's still the same. Took it on the motorway on case it just needed a little blast to clear things out..... But didn't have the guts thanks to previous experience!! Any other ideas anyone?

Shahpor · October 14, 2016

Can you perhaps describe the symptoms some more?

For example, once it boosts, does it go well? Will it rev cleanly to the redline? Is there any smoke out the back? Any noises/coolant problems in the engine bay?

Lastly, you say the DPF was unblocked, but you didn't say how?

scott1977 · October 18, 2016

Once the turbo kicks in around 2800rpm it feels fine. but when I was on the motorway, unless I was accelerating, therefore spooling the turbo, it felt juddery and lie it could cut out. Ive not tried it to the redline to be honest mate, There is not any smoke, since the DPF was unblocked. He used a chemical to remove all of the soot etc.

I cant see any coolant problems, or hear any strange noises. Its just very odd that its happened since the DPF blocked. Like its backed up somewhere else.

Shahpor · October 18, 2016

Hang on, is that a typo or are you saying the turbo doesn't boost until 2800rpm? If that is not a mistake, then something is very wrong since it should start boosting at around 1600rpm and should be going well by 1800-2000rpm.

Also, did he take off the DPF to clean it?