Loss in power on 4.2L

[Neuner]

Had a AMC 258 i6 / 4.2l with 33s and 3.31. Did just fine down the highway at 60 to 65. Any faster and it was stressing out. Had good pickup but struggled to climb long steep hills at speed. Got 15-16 mpg figured with GPS.

Mine had a Weber 32/36 carb, nutter bypassed, ported vacuum and timing set at 8-9 BTDC. If the timing was moved either direction, the power suffered. If the carb mixture was budged slightly, it suffered. If the air filter was dirty.....it suffered. You're just going to have to pick up a wrench and learn the sweet spot for your setup.

 

[kaotik1]

Had a AMC 258 i6 / 4.2l with 33s and 3.31. Did just fine down the highway at 60 to 65. Any faster and it was stressing out. Had good pickup but struggled to climb long steep hills at speed. Got 15-16 mpg figured with GPS.

Mine had a Weber 32/36 carb, nutter bypassed, ported vacuum and timing set at 8-9 BTDC. If the timing was moved either direction, the power suffered. If the carb mixture was budged slightly, it suffered. If the air filter was dirty.....it suffered. You're just going to have to pick up a wrench and learn the sweet spot for your setup.

Thanks Neuner... I honestly think its the carb and timing that need tuning. I ended up taking the jeep to another shop to see if they can get it tuned properly. The jeep has a Holley Carb which from what I have read isn't really the pick of choice for Jeeps. Lets see if the shop its at can actually get it running.

 

[Lumpy Grits]

Hey OP-Any updates?
LG

 

[kaotik1]

Hey OP-Any updates?
LG

Ended up needing a carb tune and timing adjustment. Jeep fires right up and stopped smoking and can actually go up an incline without losing all power.

 

[Lumpy Grits]

LG