No power until 2000 rpm

**Tomszs** · 26th June 2020, 20:36

Hello, so another thread about no power until 2k rpm problem.. I have read many threads on this and other forums, but still can't find the problem and also have some extra questions. Btw it's Signum 2008 1.9cdti 150hp.

Firstly the car was running perfect month ago ( at least it was perfect for me cause I haven't drove any other car with same engine but still there was quite good response in low rpm range).Accidentally I read that I can make it more responsive after MAP cleaning, so I thought why not (maybe it was bad choice..). I have cleaned the MAP with electrical contact cleaner and I noticed that there are no power until 2k rpm if I floor pedal, after 2k turbo kicks and everything is fine (some people from other threads saying that after they read 2k rpm black smokes are coming but for there any no any smokes.. I mean I never notice any black, white or blue smokes). So I though that I probably damaged my MAP sensor and ordered a new one but no difference after replacing it.. Maybe it was defective.. I shipped it back and waiting for a new one.. Anyway I assume that my sensor that I cleaned is good , so currently after reading many threads what I have done:

Fully cleaned EGR (firstly I cleaned only the half of it, then I found that solenoid can be sticky so I checked it, seems that it moves free and it's really clean (maybe last owner already cleaned it)
Cleaned throttle body
I don't know how to check swirl flaps but they are moving freely I guess and they look clean enough from outside, I don't know if I have modified inlet manifold cause I can't find part number as described in other thread on this forum, but maybe someone can tell from photo of how they look like? (https://previews.dropbox.com/p/thumb...ue&size_mode=5)
I tried to disconnect and also blank EGR with oval plate which I made from stainless steel (still haven't blanked with square plate but not sure if it's needed)

So after all those things I done there still no power at low revs.. Also one more thing, there are no fault codes after I done diagnostics, only there was fault after I disconnected the EGR. Any tips

?

**northpole** · 26th June 2020, 21:05

You might want to clean the MAF sensor or see if when you disconnect it it makes a difference on power of ot does you'll need a new one...

Also when is the last time you replaced the fuel filter?
If you can't find it in the cars paperwork than I would replace it and run at least an injector cleaner... but I usually run a diesel purge as soon as I buy a diesel, thatveay I know that the injectors have had a proper clean out.

**Tomszs** · 27th June 2020, 07:33

Originally Posted by northpole

You might want to clean the MAF sensor or see if when you disconnect it it makes a difference on power of ot does you'll need a new one...

Also when is the last time you replaced the fuel filter?
If you can't find it in the cars paperwork than I would replace it and run at least an injector cleaner... but I usually run a diesel purge as soon as I buy a diesel, thatveay I know that the injectors have had a proper clean out.

Forgot to mention about MAF.. I tried to disconnect, it's much worse that it was before, so I guess MAF is alright. I have changed fuel filter about 5000 km ago, haven't thought about injector cleaner, maybe worth trying.

**northpole** · 27th June 2020, 07:51

Originally Posted by Tomszs

Forgot to mention about MAF.. I tried to disconnect, it's much worse that it was before, so I guess MAF is alright. I have changed fuel filter about 5000 km ago, haven't thought about injector cleaner, maybe worth trying.

if you are going to use an injector cleaner, use LiquiMoly diesel purge... basically you run the car straight of the stuff and it'll clean the injectors rather quickly, what ever is left you chuck in the tank as than it helps clean the rest of the fuel system... here is how to do it on your engine

**Tomszs** · 27th June 2020, 19:10

Gonna try that diesel purge cleaning. Maybe any other thoughts?

**Inovator** · 28th June 2020, 01:28

Did you scan it for errors?

**Tomszs** · 29th June 2020, 07:32

Yes, no error codes, only code: p0400-5a exhaust gas recirculation flow insufficient detected but it's because I have blanked EGR, before blanking there were no codes.

**northpole** · 29th June 2020, 08:47

Remove the blank wipe the error code and take it for a spin... I'm quite sure the EML can put the car into limp mode. Thus resulting in less power at low rpm.

**Dog_Book** · 29th June 2020, 08:49

Correct, it ****es the ECU off no end.

**Tomszs** · 1st July 2020, 20:37

Originally Posted by northpole

Remove the blank wipe the error code and take it for a spin... I'm quite sure the EML can put the car into limp mode. Thus resulting in less power at low rpm.

Removed the blank and wiped error code, no EML now but no difference in power either.. Found thread about vacuum hoses which can also cause similar problems, so checked all hoses, they are still original GM ones but seems to be in good condition.. Anyway I probably gonna order new ones and change them hoping that maybe new ones will make any difference.