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Getting an MSCF error when I am accelerating hard in higher gears. Message has been an overboost error.

Dont seem to get this when accelerating in any low gears, and only seems to happen in 4, 5 and 6. If I go for gentle acceleration in these gears, then not a problem, but if on an uphill stretch or looking for a hard push of speed eg overtaking then it comes up with the error and engine goes into withdrawal above 3000 revs

Last year I replaced the EGR for another problem, and that sorted out things. I also replaced the MAF before that, and have had the turbo hose replaced where its rubbed against the engine mount.

Any ideas why this happens only in the higher gears???
 

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Still sounds like the MAF sensor to me.
 

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Yep, have that same issue myself, and only just started during the cold weather. Was it a P0235 error?

Sheesh search function here is very poor
This is my post
http://www.alfaowner.com/Forum/alfa-147-156-and-gt/201305-p0235-boost-pressure.html

Over 3k revs management light comes on. People on here have suggested MAP sensor, all turbo pipes, EGR and lastly turbo. Checked my MAP and is was dirty so cleaned. No difference. Haven't had time to do the rest.

Hoping it's not the turbo.....

Have you read the error codes?

Let us know if you get it resolved.

Good luck and Cheers
 

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You get this error when the boost requested by the ECU doesn't match that measured by the MAP sensor, you probably get this in higher gears because the boost is on for much longer and the engine has to work harder ...


It won't by your MAF sensor as that doesn't give rise to a boost failure (as it's only used for fueling) ... give your MAP sensor a clean (only a 5 minute job), also see if you can get some real time diagnostics too
 

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I am having a similiar issue with my 147 JTD and would be interested in whether or not you have managed to fix your problem and how.

If any one has any idea on how to help with this I would really appreciate it, its been an absolute pain in the backside for the last month or so.

A bit of background on mine;

When I start up after not having driven for a day there is no ECU light. Heavy acceleration in low gears doesn't seem to affect the ECU however there is a high pitched squealing noise. Once I get into the higher gears heavy acceleration or maintaining medium acceleration on flat or incline results in ECU light coming on and all power being lost above 3000rpm (cannot barely get over 3000rpm). To give a perspective of how low the power is, I start losing speed with my foot down on a slight incline on the motorway doing 70mph!
So, if I stop and restart the engine immediately the ECU light comes on but acceleration is back to how it was before until I accelerate as before in high gears. This time there is no noise from the car, (the ECU light is already on when i restarted) and with no warning the power is gone.

I've had my EGR valve, MAP sensor and a turbo pipe changed to no avail

I took it into a diesel "specialist" who said my vanes were stuck on my turbo as the ECU was coming up with overboost. This theory was soon eliminated by carrying out a simple check on the turbo vane actuator whilst getting someone else to start the engine. Actuator moved fully if a bit slowly. I unplugged the vacuum hose and took it for a drive - no boost until about 2700rpm and then I get normal boost. This suggests to me that the vanes are definitely moving as I get boost at low revs with the vac hose on and at high revs with it off. Infact when I plugged the vac hose back in the actuator was moving much more smoothly than before!

So I thought I'd narrowed it down to the VNT Solenoid which controls the vacuum to the actuator and hence movement of the turbo vanes. Swapped this for a new part but the car is still running exactly as it did before. :( :mad: Do I need to clear the fault code for it to make a difference?

I'm running out of ideas now, can the MAF be giving lower readings than the actual resulting in more air in the engine than the ECU thinks? but then this wouldn't be overboost. Piping seems to be fine too, couldn't be the vac pump could it? Or could it be an incorrect MAP sensore fitted? there is a difference between the 8v and 16v sensor right?

Any help would be more than welcome, I am at my wits end with this and do not trust any garages to have a look at it now! The garage that told me the vanes were stuck recommended I replace my whole turbo with a new one and quoted £800 for just the part!!!!!!
 

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have u tried cleaning the vanes?

that's what I'm going to do
 

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I've had this problem on my 156 JTD 20v since I bought it and that was nearly 30k miles ago. I have posted on here before and as I can still see nobody has ever truly manged to solve or correctly diagnose the cause of 'the loss of power at 3000rpm' issue. To be honest I very rarely need to go over 3000 rpm and I do 50 miles a day commuting. I guess I have just got used to that way of driving now, but it is frustrating on those occassions where you boot it out of a slip lane and then the power dies on you and you have to find a suitable point to restart the engine.

I decided not to spend money on replacing every possible sensor until someone could actually definitively describe the cause of the fault. It would just be a waste of time and money.
 

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I've had this problem on my 156 JTD 20v since I bought it and that was nearly 30k miles ago. I have posted on here before and as I can still see nobody has ever truly manged to solve or correctly diagnose the cause of 'the loss of power at 3000rpm' issue. To be honest I very rarely need to go over 3000 rpm and I do 50 miles a day commuting. I guess I have just got used to that way of driving now, but it is frustrating on those occassions where you boot it out of a slip lane and then the power dies on you and you have to find a suitable point to restart the engine.

I decided not to spend money on replacing every possible sensor until someone could actually definitively describe the cause of the fault. It would just be a waste of time and money.
+1
I've come to the same conclusion. Lots of well meaning posters but there doesn't seem to be a definitive answer.To be fair it's impossible to diagnose accurately over the net.
There seem to be a lot of people out there who replace everything and still have the problem. My problem is intermittent so I live with it.:(
 

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ahh right, I don't get an error etc - its just a flat spot.

But this did happen once, when the mrs was driving, it was down to the clutch pedal sensor sticking causing an few errors.
 

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Could it be linked to slipping clutch? as i have had this in 6th when you give it a bootfull the revs go right up and you get the message.
 

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nope clutch is fine, no slippage in any gears, i think it was down to the mrs holding her foot over the pedal :eek:
 

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Was having the same probs as fozzie3369. Replaced boost hoses, VNT solenoid/all pipes but was exactly the same and getting P0238 Boost Pressure and P1238 Air Quality faults, so I blanked off the EGR Valve at the Inlet manifold and voila.... goes like a stabbed rat!! Still shows MCSF (P1238 due to EGR blanked) but performs great right through the rev range, no hesitancy, mpg better and almost no black smoke!! I might replace the EGR later but I can live with the MCSF for now (will check every few weeks for any new fault codes though). Like loads of fellas on here have said, for the 30 mins it takes to blank it off, it really is worth it.
 

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tomfromtelford - now that you mention the clutch, I do have a clutch error code as well, however, I cannot see how the problems I'm getting are linked to the clutch (overboost, loss of power).
I'm considering giving the turbo a clean next, not sure what else it could be:(

Something else, as I came off the motorway aafter my normal monday morning commute my car was making some hurrendous noises at 1500-2000 rev plus. Its done this a few times before and it seems to only happen after a long drive or when the engine is up to temperature and been running for a while. The noise is audible over the engine and i'm assuming its the turbo after all the problems i've had with it. As well as the engine noise I can hear a sort of lawnmower sound, maybe like a vacuum cleaner when you get a carpet mat stuck in it. :eek: Has any one else had this who also has the same loss of power and overboost problems?

I'll post any findings. Determined to get to the bottom of this.
 

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Well as mentioned I don't get any errors, mine is just a lack of pier over 3k in high gears, feels like I'm down on boost or underfueled etc...

When I had my one over boost error and limp home, the garage said the clutch pedal had stuck slightly, giving and error to the ecu I.e. effecting air/fuel mix etc...

Don't know if this is still a problem, as it go stuck up when my pin in the clutch went, I pulled it back out and seems to work fine, they did say it gives a Reading that it is slightly depressed, this might be causeing somthing?

I'm going to look to vene cleaning / vnt and go from there.
 

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Right I've had a play with my tunning box, it seems to be over fueling it and is noticed at high revs, a few tweaks and a thrashed run has sorted it for now :)

i had upped the settings before I had my egr changed so was prob running to rich - not enough air to burn the fuel.

Feels like new :)

will keep you posted if it goes back to the way it was.
 

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Ps mine was the maf
 
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