1985 K5 350 always running rich?

[DnS421]

Hey guys, so I have a 1985 k5 with 350 and 4 barrel eldelbrock that was rebuilt by a highly reputable carb builder and the truck starts super easy and runs good it seems but no matter how you tune it it runs so rich that you can't hardly even drive it for the fumes! What should my plan of action be?

 

[Shorty81]

Make sure your PCV (positive crankcase ventilation) is in place and functioning properly. If not you will get vapor inside the cab. My truck runs a tad rich, but I don't notice it inside the cab.

 

[fast 99]

Are you sure it's rich? Does it burn your eyes that would be lean. Check fuel pressure should be no more than 8 lbs actually closer to 5 or 6, is choke opening and if not does it need or have 12v power?

Did you adjust the idle mix? That cannot be set correctly on the bench.

 

[Ricko1966]

A bad plug or wire can cause rich. So can a dead cylinder or a vacuum leak,retarded timing

 

[DnS421]

Make sure your PCV (positive crankcase ventilation) is in place and functioning properly. If not you will get vapor inside the cab. My truck runs a tad rich, but I don't notice it inside the cab.

The PCV is new but the grommet around it is not in the best of shape, I wouldn't think just the grommet would cause this though right?

Are you sure it's rich? Does it burn your eyes that would be lean. Check fuel pressure should be no more than 8 lbs actually closer to 5 or 6, is choke opening and if not does it need or have 12v power?

Did you adjust the idle mix? That cannot be set correctly on the bench.

yes, my bad. I must've confused the two in my head when writing the post. It does burn he eyes a little, the fumes are inside the cab and just as bad when standing around the truck. My wife even said it gave her a headache when she followed me home after picking the truck up from having the carb fixed. I have a manual choke so it wouldn't receive any power correct? I may take the truck back to the carb builder and have him check the adjustment over as he is very good about fixing anything that seems off with his work for free.

A bad plug or wire can cause rich. So can a dead cylinder or a vacuum leak,retarded timing

All plugs and wires are brand new, the distributor and everything is new also, I thought it was timed properly but I may have to grab the timing light and double check.

 

[SquareRoot]

I had the same problem with the same truck/engine. I finally threw the Edelbrock carb in the trash and installed Pro-Flo efi. Guess what? I could tune it rich, lean and anywhere in between and it still stunk. So I built a crossover and installed a Magnaflow Hi-Flow Converter. Guess what? Yep, no more fumes and zero loss in power. The cat is back

 

[fast 99]

Manual choke forget that suggestion.

Burning eyes is usually excessive hydrocarbons [HC]. A sign it is running lean. There are a lot of causes some are not carb problems.

Yes if possible take back to whoever rebuilt it preferably on the vehicle.

Over the years have tossed out a lot of unrebuidable carbs of all designs. However, most are fixable just takes more time and a deeper dive into the circuits.

 

[Bextreme04]

Yep, properly tuned carb and put some cats on it. I'm running dual 3" heavy duty flowmaster cats right after the collector on the long tubes. H-pipe is right after the transfer case. This is on a slightly hopped up L29 454 and I'm using the same setup on my 2011 Suburban with the 6.2 LS setup. For a smogger 350, you could do a single one after the 2-1 merge or run these right after the collector if you have long tube headers. I see you're in Tennessee, so I'm guessing no emissions testing? 1984 would have had a pellet cat originally, so if you do have some kind of inspection, the flowmasters wouldn't pass. For a mild 350, depending on what you want for exhaust(or what you already have) you can do small long tubes with a 2-1/2" collector, then get federal compliant 2-1/2" converters at the collector and then continuing into the rest of the exhaust(2-1 or true dual all the way back). These Magnaflows are federal compliant.
https://www.etrailer.com/Catalytic-...v1sCvO07b1DC6PgzwAY_mh0otiOHSPiEaAplbEALw_wcB

 

[DnS421]

Thanks for the suggestions guys, I'm gonna put the timing light on and the. If that doesn't fix it I will take it to my carb builder to be fine tuned and then if that still doesn't fix it I will take it to my local exhaust shop, they do great work and the exhaust system is old and rusty anyway so it's about time to give it some love!

 

[fast 99]

If indeed running rich cats will convert exhaust to a rotten egg smell. They may also melt down or plug up. Need to fix the problem.