Volvo RWD 120-130 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 1/2003 120-130 INDEX

[<<]  [>>]


 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

Cracked Exhaust Manifold 120-130

Up date - With the cure...
I finally found the problem!
After trying everything I knew, guessed, read,and was told and the help from various sources.
I decided to, essentially, start over.
I removed the carburetors with the intention of going completely through them. There had to be something wrong with them!
The heat shield looked a bit shabby so I decided to pull it off and paint it.
There it was! No, there they were! The exhaust manifold had a 4" crack in the center and second crack in the #4 runner that wraps about 2/3's of the way around the casting.
The only clue I had to this was that the engine sounded rather loud and when I hooked up a vacuum gauge the needle shook violently. Vacuum gauge info says this indicates a sticky valve or a broken valve spring.
After finding the cracks, I Googled "exhaust manifold cracked lean carburetor" and found my experience was not an isolated case. I replaced the manifold (it is good to be a hoarder) and like a miracle things are as they should be.
It seems this is a "lost diagnosis" fuel injection will automatically richen the mixture because of the extra oxygen in the exhaust and just give horrible gas mileage. A carburetor can't make an adjustment, Thirty years ago, given the symptoms, a mechanic would have just said "ya prolly got an exhaust leak".

Thanks for your help,
-TR






THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD

New 1 SU Guru needed. B20 Lean Stumble [120-130]
posted by  TR Conn subscriber  on Tue Mar 6 01:19 CST 2018 >


<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.