Engine 93 Cobra, Dreaded 94/44, Terrible Fuel economy, Runs great! (FIXED)

someone82 said:

Short story, been restoring my father's 93 Cobra, top end, front end, exhaust all freshened up. It's running great and feels better then when it left the showroom floor but my fuel economy sucks (11 mpg). She is basically stock on the motor besides an adjustable fuel pressure regulator (set at 39), 165 pump, and a pro-m maf (factory bit the bullet).

So I am getting 94/44 KOER test (passes key off test), air pump is new, solenoids check out OK (ground out OK and operate), wiring is correct, vacuum lines are correct, diverter is new (old one collapsed), check valve ok, cross over pipe is clear, and are the heads.

When engine is cold air is diverted to the heads, once some temp is built air is diverted to the cats. Now here is the problem, when the engine is revved and comes down on decel, air is diverted to the heads, not bypassed as stated in Jrichker's posts. I am stumped the bypass is responsive to vacuum, and what I'm stating sounds like the solenoids are reversed, but they are not as the diverter is acting properly when cold and warm at idle.

Any advise before I bite the bullet and take it to the stealership?

Thanks, Matt

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StratTone said:

I've never tried to actually repair anything in the air diverter set up but what 5L5 says makes sense to me. If everything is clear and the solenoids are switching correctly and the pump is working then maybe the check valve is bad.

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