Emissions solenoid valve

[rooks]

Hi all,

Does anyone know the purpose of the emissions solenoid valve on our cars.

Part number MD320313

photo:

where it lives: (courtesy of camskill.co.uk)

 

[veegeeta]

pretty sure thats the boost solinoid,thats what my boost tap is taped into( it controls factory boost)my bad looked at wrong one in your pic!

 

[lathiat]

I looked this up in ASA, there's two very similar valves in the picture, both part list as "EMISSIONS CONTROL"

12421T (MR212636) and 12421S (MD320313)


The bottom valve (12421T) appears to connect to the wastegates, so that's your boost control solenoid.

The top valve you refer to (12421S) appears to connect to the fuel pressure regulator. I'm not quite sure *why* the FPR needs a connection to a solenoid, and I may be reading the diagram wrong, but seems to be the case. It also doesn't show where the other end of the solenoid connects to, it's a dead end.

 

[rooks]

Mystery indeed. Wonder if I can get a better look with the MAF out of the way tomorrow.

 

[rooks]

I wonder if the Emissions control valve equals the EGR valve.

abit of light reading here on emissions controls --> http://tech.mirage-performance.com/...on's Manual/Ch 4 Driveability & Emissions.pdf

 

[lathiat]

Reasonably sure the EGR valve is elsewhere.

 

[Guest]

The names are always confusing.

The one on the left (MD320313) is the fuel pressure solenoid, which connects to the fuel pressure regulator and to just behind the throttle body (as shown in that diagram from ASA if you follow the hoses).

And yes, the other one on the right (MR212636) is the factory boost control solenoid.

Here's another diagram that may help too.

This shows where it takes the pressure source from.

 

[lathiat]

Anyone know what the fuel pressure solenoid actually does?

 

[Guest]

Controls the air pressure going to the FPR's diaphragm.

 

[lathiat]

OK that much I could have told you

I guess my real question was.. obviously this is some kind of ECU tunable.. it has to bleed pressure from the FPR for some reason? Does it regulate pressure somehow?

Wonder if there's a map for it?

 

[naughtika]

our FPR are partly mechanical and electronic.. ecu controls the pressure as you mentioned...

i was talking to steve about these.. as he found out that most of the oe wastegate solenoids are stuffed.. what's the chances of the FPR solenoid being stuffed as well..

 

[VOLK]

If you simply use a mechanical regulator, it will raise pressure with boost and lower with vacuum. Low rail pressure isn't ideal for cold starts so the solenoid limits the vacuum at the regulator when necessary.