Any late model, EFI engine is going to be very sensitive to vacuum leaks.
Here are a couple things to look at with your SR20DET engine:
1. Did you plug the hole at the back of the intake plenum (the lower part)
where the brake booster hose screwed into the plenum? There is a cad plated
fitting with a 90-degree end on it which screws into the intake plenum. If
this was not plugged you will have a HUGE vacuum leak. This item is missed
by lots of 510 guys when they do their swaps as it can be hard to see.
2. AAC valve. It is fairly common for the AAC valve to get plugged up and
not function at all. I rarely see vacuum leaks at this point, but the car
will not idle if it is not working correctly. My business stocks new,
genuine Nissan AAC valves for the SR20DET engine for $150 with the gasket.
3. Do you have all the fittings by the throttle body plugged or connected,
including the one hidden on the underside? One will have a vacuum hose going
to the fuel pressure regulator, and the other to the wastegate on the turbo.
There should be two others which will need to be plugged as they went to the
charcoal canister on the original setup. If they are venting to atmosphere,
you will have a vacuum leak there.
Take a look at this stuff and let us know what you find,
SR20DE(T) Swaps our specialty
The beast is agonizingly close to being roadworthy. There is a vacuum leak
the SR20DET that seems to come from the idle air control valve. My main man
Mike Abssy @ Schrader's has removed but there is no obvious breach in the
gasket or cracked housing. Any suggestions? Any experience with this
problem? Michael Spreadbury? We have ordered a new gasket and intend to
reinstall the valve in hopes of curing the problem. Any info would be
and please respond to both Mike (cc'd) and I.
'66 SPL311 SR20DET
North Hollywood, CA