Fuel smell at high rpm during hard acceleration (fixed with catalytic converter)

[pizzaman09]

1990 Renix 4.0L, when I rev out the truck hard in first, second or third gear, I get the smell of raw gas for a few seconds.  Does anyone have any thoughts on what it could be?  Typically I'd suggest this smell occurs if I get near 4000 rpm plus.

[pizzaman09]

On 10/13/2023 at 8:11 PM, saveevryjp1998 said:

What fuel injectors are you currently running and when was the last time you replaced your fuel injector o rings along with the regulator? You could always rev out by hand the throttle body in park and checking for leaks. Renix oem injectors are notorious for cracked bodies in the housing. Many renix were often found years back with fires originating there. With built up oil from blowback, valve covers, leaking manifolds, leaking fuel, poor connections with c 101 connectors all make for the perfect storm if neglected. The orings are also easily cut or nicked during install if you replace them.

Thanks for the reply, definitely some things to look at.  I replaced the injectors a year ago with Chinese knock off 4 hole Volvo injectors, they work phenomenally.  The o-rings were all new at that time.  The regulator is probably original with 260k miles on it.  

[pizzaman09]

I just wanted to update in case someone found this useful.  My fuel smell at high rpm during hard acceleration turned out to be a bad catalytic converter.  A big chunk of the cat element on the input side was broken, rotated sideways and blocking gas flow.  My mechanic had found the issue by hitting the converter and listening to it rattle.  

 

I put in a new Magna Flow cat and now the smell is gone!  On the plus side the rattle is gone too.  Additionally there appears to be a bit more power through the mid and top of the rpm range.

[Ωhm]

4 hours ago, pizzaman09 said:

My mechanic had found the issue by hitting the converter and listening to it rattle.

 

Gotta love the skillset that comes with experience.