Pressure in Inlet manifold, Anyone had this before?

[KarlT]

Have lots of running (I should say non-running) issues with my 2.1dj. But I am getting back pressure into Inlet Manifold. Leads are in correct order. Compression is good. Its a recon engine is it possible for the valve timings to be slightly out (opening too soon,too late) letting pressure back into Inlet Manifold.
I can't see any other reason, but what do I know.
Its hydraulic tappets (I think) so can I go round checking them like the good old aircooleds?

[California Dreamin]

Are you sure it's 'pressure' as in blowing out? because petrol engines naturally produce vacuum in the inlet manifold (thats what is used for the brake servo).

Martin

[KarlT]

Thanks for reply Martin, but no, I'm talking blowing/blasting out past idle stablizer & rubber parts on manifold. Only place pressure like that can come from is cylinder (valve open too long) or I'm getting fuel backed up in manifold & then it ignites. (Maybe valve isn't opening enough.)
Quite scary when leaning over engine!!!

[California Dreamin]

Perhaps your first step should be to do a compression test, see if you have any burnt valves.

Martin

[KarlT]

Compression is good.

[syncrosimon]

Could try a leak down test to see if your valves, rings and head gasket are sealing properly. From Canadas Vanagon Subaru expert.

http://www.youtube.com/watch?v=dB_bXXRa ... re=related" onclick="window.open(this.href);return false;

E D I T

This guy explains what the leak down test can achieve.

http://www.youtube.com/watch?v=QNf0IOIv ... re=related" onclick="window.open(this.href);return false;

[KarlT]

Thanks for that Simon.
Yeah I may look into a gauge but am totally perplexed by this motor.
I have driven it, it drove poorly, but had/has good compression readings. Fuel must have ignited in manifold.
Plan is to check out all wiring connections before going any further.