So just rebuilt the eninbge in my daughters S10 Blazer 4.3 cpi. Took to get smogged and told it running real rich. he said it just dumping fuel. Told me could be leaking fuel spider or maybe bad Catalytic converter. So i pulled plentum and looked at cpi not leaking. Looks good. So I ran fuel pressure test and it leaks off fast. I pulled return line off and tested at it not running back into tank. So then I test fuel pressure at fuel filter and its leaks off their. So I know problem is comming from fuel pump. That still does not tell me why its running rich. Smog guy said to change 02 also but told me that 02 alone would not cause it to dump as much fuel as it is. So anyone have any ideas? New Catalytic converter is $220 instaled. I just want to make sure its not somthing else before I buy the new cat. I heard could also be tem sensor? If anyone else has any ideas please let me know. I got 02 and will replace aswell.

 

i dont know for sure but i do know a little fuel pressure off and these cpi engines get all Carrot Top on you.....