'76 Air Bypass Valve (ABV) rebuild ideas? (1 Viewer)

Joined
Feb 6, 2021
Messages
4
Location
Centennial, CO
Hello Mud Nation! I'm a newb. Had a '72 back in the day, and bought a '76 about a year ago to relive the glory days.

Recently replaced the smog pump. (housing cracked.)

Engine is now starting hard & have smelly exhaust. Guessing it's the ABV. Would rather not bypass the smog pump.

Can't find any aftermarket options, and would rather not buy a used one that may not work for $90.

I know these aren't build to be opened up, but am willing to try. Don't know much about how these work, but willing to explore . . . .

Any ideas are greatly appreciated!
 

fjc-man

SILVER Star
Joined
Mar 21, 2014
Messages
854
Location
Commerce City, Colorado
Fiddle with the valve assembly a little, might just have shrapnel pieces from the old air pump stuck in it obstructing operation. Is your air pump replacement a rebuilt?
 
Joined
Feb 6, 2021
Messages
4
Location
Centennial, CO
Fiddle with the valve assembly a little, might just have shrapnel pieces from the old air pump stuck in it obstructing operation. Is your air pump replacement a rebuilt?
Thanks for the idea; bought a replacement from Parts Geek- manufactured by Dorman.
 
Joined
Jan 17, 2005
Messages
5,619
Location
Southern Colorado
Engine is now starting hard & have smelly exhaust. Guessing it's the ABV.

Have you started the engine with the ABV installed on the manifold end but on the inlet/pump end, and felt exhaust shooting out - that would indicate an bad ABV? IIRC, the ABV is just a check valve to protect the smog pump. Smelly exhaust on a pre-catalytic converter FJ40 is hardly an indication of anything amiss ;). Also, an ABV should have zero impact on starting.
 
Joined
Feb 6, 2021
Messages
4
Location
Centennial, CO
Engine is now starting hard & have smelly exhaust. Guessing it's the ABV.

Have you started the engine with the ABV installed on the manifold end but on the inlet/pump end, and felt exhaust shooting out - that would indicate an bad ABV? IIRC, the ABV is just a check valve to protect the smog pump. Smelly exhaust on a pre-catalytic converter FJ40 is hardly an indication of anything amiss ;). Also, an ABV should have zero impact on starting.
 

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