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Discussion Starter · #1 ·
Hello Everyone!
I recently got myself 147 2.0ts 2001 Selespeed, with some issues ecu code regarding "P1654 Modular Manifold ". although the car worked perfectly and no idles issues. Im using Multiecuscan software.

So Recently removed all parts related to the intake including the modular manifold, replace the vacuum actuator, and put everything back togheter, even cleaned electronic throttle body, with new intake gasket etc..

Now the car does not idle right, especially cold, where theres too much vaccum in the highspeed PCV valve to a point that actually shuts the breathing pipe shut. I have followed the advice on this website Gazza82's 1998 Alfa Romeo 156 TSpark 2.0
I have checked the valve operation and cleaned it but to no avail... the car has a seriously rough Idle cold and irregular hot idle. Clearly feels like a vacuum leak, but i cannot find any, also if there was a vaccum leak, surely i wont be reporting too much vaccum on the intake side after the electronic throttle body.

Any help wold be greatly apreciated.

Thank you in advance
 

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Too high a vacuum can only be produced with engine running and throttle valve in closed position. However, you reported to much vacuum in the PCV valve so it looks like you have damaged the valve or throttle body. I'd change both and perform a throttle reset.
 

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Discussion Starter · #3 ·
Too high a vacuum can only be produced with engine running and throttle valve in closed position. However, you reported to much vacuum in the PCV valve so it looks like you have damaged the valve or throttle body. I'd change both and perform a throttle reset.
Thank you for your reply, I cannot seem to adjust the ElectronicThrottle Body, i already tried 3 times the procedure : 45 min batt disconnect, + 90 secs... etc.. to no avail.
also i cannot seem to do this in MultiECUscan software. is there a software you can recomend?
When try to reset ECU adaption , simply goes "operation failed."

PS: I have notice that it take alot of force to move the Modular VIS inside the Intake , by hand. Maybe someting is jamming it it, and the Vacuum rod cannot move it into position, hence the "P1654 Modular Manifold " DTC. can this be creating this excess vacuum?
Cheers
 

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Firstly MES is good software and we are fortunate to have it. There isn't really an alternative other than buying the hardware also which takes the cost to over £1000 (Foxwell GT85).

What exactly is the fault code description? Quoting a fault code only records where an anomaly is but it gives absolutely no information as to the nature of the fault. Can you also please detail what selection you make on MES for car details?

I cannot see how a new vacuum actuator could cause a problem are why you have found it hard to vary the manifold tract length. Did you fit a new or second hand actuator?
 

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Did you lose the spring of the PCV valve? If so then the plunger part would be sucked shut with no regulation from the (missing) spring. It's easily done, I lost mine the first time I took it off and spent 2 hours looking for it in the workshop.
 
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