Alfa Romeo Forum banner

power loss

Tags
loss
5.1K views 63 replies 13 participants last post by  joeymannero  
#1 ·
Hi
I've had a bit of a power issue as of late.

I have fitted a new egr and had a new clutch but there seems to be a lack of power under 2k rpm. This was also there prior to the clutch failure.

There is a theory towards the VNT but I will need a guide to clean this. Are there any other ideas?
I'm gonna do an oil change this weekend

Thanks
paul
 
#3 ·
lack of power under 2k points to either a vacuum leak, solenoid or as you said VNT..I would also have a look at the air filter and make sure its clean and not impeding air flow...

could also be boost leak although you would likely hear it in the cabin if its top hose.

my money is on the 3mm vacuum hose though,often if its a very small leak it causes late turbo spool and you get black smoke on acceleration.
 
#6 ·
correct, replace hose connecting to the turbo first,you can use a little touch of plumbers tape around the fitting just to make sure its airtight if you like.


I would leave the VNT for the time being, I doubt it's that, almost every thread I read where it looks as if this is the issue it tuns out to be a vacuum leak...it just sounds like that to me sub 2k lack of power is a dead giveaway, all the symptoms of EGR but I assume you have had the EGR deleted or blanked?

if not then clean EGR first and then replace the 3mm vacuum hose.

if not blanked and mapped do it at later date, but do do it.

almost certain this will sort your issues.
 
#8 ·
Fit one of these in the meantime: http://www.ebay.co.uk/itm/EGR-1-9-2...estrictor-plate-SL-Hole-/121319458356?pt=LH_DefaultDomain_3&hash=item1c3f340634

Gives you a lot of the benefits of a full EGR blank, but for a fraction of the cost and without generating MCSF errors.

Full EGR delete/blank is definitely the way to go, but a restrictor plate will do a lot of good until you can get round to the full fix!

Replacing the vac lines is a good idea... I did mine a week or so ago, whilst fitting a new VNT solenoid (mine had a split!).. Made a huge difference, well worth the few ÂŁ it cost!
 
#9 ·
Blanking plate will be next month I think :)

Replaced the vacuum pipe and hey presto it's loads better. Thank you very much everyone :)
It'd been bodged before as it had black rubber on one end of a plastic pipe and blue pipe on the other end lol.

I also found my boost pipe from the bottom of the turbo has been bodged. It has a patch of rubber wrapped around and held on with a cable tie so I will change that next.
 
#13 ·
It's also worth checking that your EGR isn't leaking. If it's been taken off more than a few times chances are the threads on the 4 bolts have started to strip and it's not sealing properly. I'm currently sourcing some slightly longer bolts to try and cure mine of this (3 are stripped), failing that its a case of helicoiling I think.
 
#14 ·
Check your vacuum is moving the vnt solenoid ( plunger thing) sufficiently by observing how far it pops out when the ignition is turned off. Compare this level of movement with what you can achieve by sucking on the pipe with the ignition off. The movement should be about the same. I think there are 4 pipes prone to cracking and the one at the back of the engine is a little fiddly to replace.
 
#20 ·
Just to jump in with my two pence, I had the same fault as described in the opening post, and was planning on doing the VNT clean, but I had ordered the EGR blanking plates too, fitted the blanking plates this morning and solved the problem straight away...
feels 1000%times better, pulls from the get go...
no need to replace any vac hoses or clean the VNT, just cleaned the EGR and blanked it off.

Gareth.:thumbup:
 
#24 · (Edited)
Glad you're making progress but there is no sense in throwing money at parts until the egr is blanked. A plate is less than ÂŁ10 and takes minutes to fit. Ignore the p0104 code and feel if the performance is improved. Even if you're not happy keeping it blanked at least the process of blanking will aid your diagnosis.
If performance isn't restored the next cheapest part is the map sensor but this is quite sturdy and rarely fails. It can be cleaned. The maf is often suspected but I don't think as unreliable as suggested. It's often the first port of call for garages who haven't been thorough with their diagnosis. Both sensors can be checked by running some data plots and seeing if the pressures make sense. As a very general rule low rev power issues are vnt and high rev issues are maf. You may have had a combination of faults. Nearly there.
 
#26 ·
Power loss above 2000rpm is unlikely to be sticking vnt. Don't take your turbo apart yet.
Could be maf but really you want to eliminate the egr from your investigations first. Work your way through the potential causes starting with the cheapest to most expensive. Ultimately you may find you have duff injectors but you want to explore all other options first.
For no cost. Unplug the maf and take for a spin. Tick over will be worse but it is possible general performance at revs will be better. If so you could need a new maf.
 
#29 ·
Hi all,

Read this post with interest and thought I'd share what I did recently but still have the same issue.

Replaced all the vacuum hoses, no change,
Removed and cleaned the EGR, no change, ( took it all apart and pin moves freely)
Cleaned the intake manifold where the EGR connects to, No Change
Checked all turbo hoses thoroughly, removed and replaced with new ones, No change
Removed and replaced air filter- No change
No errors and at 2-2.5k pulls like a train
Removed and replaced MAP - No change
Removed and replaced MAF- No change
Sucked on the pipes and the VNT moves in and out ok

No errors at all in Multiecuscan

Spoke to an alfa specialist and was told " some of them just don't pull under 2000 revs"

Basically emptied my wallet, sucked and blew on a load of pipes, scraped a few knuckles and still no change !

Any other suggestions ??