[kenclarke]

Posted a couple of weeks ago about a turbo that had gone in wife's car. Sourced a turbo, fitted and though all ok, but alas no.
Had ongoing fault with Egr also but now fitted new Egr to rule this out. But when accelerating hard lots of black smoke and low on power, throwing p0235 code up. I think hoses are OK as checked when fitted turbo but will check again. Could it be a map sensor with all smoke or is possibly sticking variable vanes on turbo (hope not) or any other suggestions?

 

[samsdads156jtd]

have a look at this thread it may help a bit, hopefully...

http://www.alfaowner.com/Forum/engi...65120-p0236-and-p0235-fixing-these-codes.html

 

[mirlock]

It does sound like a air leak in turbo hose or intercooler . as sam mentioned have a good read.
But when checking hose etc get someone to sit in the car and rev it so you will be able to feel or hear leaks.

 

[_The_Editor_]

My money's on the vac hoses for the VNT actuator and/or the boost solenoid valve... These crack/fail over time, and your turbo get's stuck in low-boost position...

Very lackluster to drive, and chucks out smoke a MCSF error, and limp mode when you hoof it... Managed to drive a week without a boost solenoid, but by god it was boring to nurse it about....

 

[kenclarke]

Just had both intercooler hoses off and they're OK. The small bore pies to VNT also look ok although one is rubber to turbo and other is rigid plastic going to back of head. Turbo solenoid is moving when you start car and moves freely when you suck on tube. MAP sensor was black and covered in gunk, cleaned as best as possible with brake cleaner. But would MAP cause all the black smoke.

 

[kenclarke]

Bit of an update. Looking at some other posts I've done test to check turbo vanes. I've took of vac pipe from VNT to turbo actuator and blocked it. Took car for a spin and car running exactly same upto 2500rpm which from what I've read points to sticking turbo vanes. What's throwing me is when you start car the turbo actuator is operating off the vacuum, if vanes were sticking would the rod not move?

 

[R.T.]

Have you tried running with the egr valve disconnected electrically, or better still, blanked. The P0235 fault might mean that it's being held open all the time. With too much exhaust gas getting into the engine you will have poor combustion, smoke and power loss. Your VNT system, which seems to be working, won't have much effect at low revs because the engine won't be able to generate the gas flow to get the turbine spinning, regardless of the VNT position.

(Running with the egr disabled will generate a code but iirc you won't get limp mode.)

Edit: Beg pardon Kenclarke, I misread P0235 as egr circuit failure, instead of boost sensor circuit failure. Forget the above. Have you checked the inter-cooler for leaks?

 

[halftone]

What's throwing me is when you start car the turbo actuator is operating off the vacuum, if vanes were sticking would the rod not move?

With mine the actuator was moving and could be pushed forward ~1cm by hand, but did not come fully forward to the stop. ePer indicates 1cm is full movement. Oh no it isn't! Full movement is ~2cm on my 147 16v 150.

It's difficult to test by hand, as you can't see much and hand pressure is fighting the (stiff) vacuum actuator. If you buy a cheap Mityvac-clone vacuum gauge from eBay and connect that to the actuator, the lever should move smoothly through the full range using 0-17 or 18 in.Hg vacuum (the actuator is rated at 0-20 in.Hg)

I took the turbo apart and found very little carbon but surface rust in the turbo casing that the vanes were jamming against, possibly formed whilst the car stood unused for a few months. Easily removed with carbide paper. Fine since, goes like stink.

 

[kenclarke]

Another update, checked vacuum to actuator today and all ok working as it should, no issues with Egr and all hoses double checked again. Out of curiosity I removed air intake pope from air box to turbo and found the issue.
So thanks everyone for input I'll be back to let you know how things are when I change the turbo again for second time in 3 weeks ?

 

[_The_Editor_]

So thanks everyone for input I'll be back to let you know how things are when I change the turbo again for second time in 3 weeks ?

Ouch... That'll do it....

Was it a new/recon unit, or a second hand turbo? DIY fitting or local garage?

 

[kenclarke]

Second hand turbo, luckily got 3 month warranty. And I fitted myself, full engine flush before I dropped oil and primed turbo with fresh oil before I fitted it.

 

[halftone]

Presumably the bearing was OK when fitted? And now... isn't.

When I had mine off and apart, [email protected] said it wasn't necessary to replace the oil feed pipe but it was a good idea to remove the (very fine) gauze filter in the banjo bolt that attaches it to the block as it blocks up far too easily, starving the bearing of oil. I had to drill it out, as it's cased in plastic.

 

[Autolusso]

Second hand turbo, luckily got 3 month warranty. And I fitted myself, full engine flush before I dropped oil and primed turbo with fresh oil before I fitted it.

That is caused by debit in the intake and not a faulty turbo, very unlikely they will warranty that

You have more issues than just turbo and EGR

Intake needs to be completely stripped to remove all contamination, possibly replace the intercooler as there will be contamination in there

Ned

 

[kenclarke]

Yea bearing was fine when fitted. Until I get turbo off for proper inspection I can't tell if it's bearing failure or something been sucked up on inlet side and had contact with blades.

 

[Autolusso]

Yea bearing was fine when fitted. Until I get turbo off for proper inspection I can't tell if it's bearing failure or something been sucked up on inlet side and had contact with blades.

You might find this useful

How to prevent turbocharger failure through 'impact damage'

Ned