Sirgolfsalot

Hello, so i've been having trouble with my 1992 f150, 5.8l. running rough and running rich, started after i did a tune up... I bought a code reader and it came up with 2 codes. The 1st was 173, o2 sensor fault/rich, which i replace in my tune up... i think i know how to bench test it to see if it is ok.
The 2nd code was 334, EGR closed valve voltage high??? I don't know what this is or where it's located?? Should i replace it??? Any help and/or pics would help!!!
Thanks

ymeski56

For your own knowledge, you should buy a maintenance/repair manual for your truck. Then you'll know where everything is! It will save you alot of time. I think your error code means your EGR valve is stuck shut. So the EGR isn't providing secondary air when demand is made. Test it for mechanical function & internal diaphragm integrity, then take it off and clean it. Don't forget to make sure the portways where it mounts are clear. Look on the passenger side of the air intake manifold. That,s where it is on my 302. After you deal w/ the EGR Valve situation, pick up a can of "SEAFOAM" https://www.f150forum.com/f72/how-seafoam-eighth-gen-f150-1987-1991-a-31505/

Sirgolfsalot

Thanks for the info, i found it but no luck on the manual yet..none in stock but will be ordering 1.
So i cleaned out the EGR valve and it seems to be working fine... but what i found is that the egr line is broken!! The line from the bottom of the valve to the manifold. Seems to broken right at the fleck portion of the line, but it fits over it pretty good. Would this make the opperation the valve not work right???

ymeski56

The valves probably working fine. They're pretty bullet proof. But it would be like you turning on the faucet w/ a broken main line. Sure it works but whats the point. There's nothing coming out of it. I've heard their a little pricey
& special order. Probably $10. at the bone yard.

conman365

For the manual, try half price books.
Thats where i got mine for cheap.. 10 bucks

Sirgolfsalot

Allrighty then, Thanks!!... I'll get looking for one and let ya know how it goes!

ymeski56

That will probably do it for you. I'm serious about the "Seafoam". If you've been running rich for a wihile, your combustion chambers are carboned up. Your truck will thank you!

Sirgolfsalot

Ya, i been adding seafoam to my gas for a couple months (only a couple times though) but i be doing what you recommended once i get the tube replaced.... THanks

mikeylikesit

I had these exact codes on my '95 and after unnecessarily replacing some parts that weren't the problem, I found that my vacuum canister (the coffee can) had a hole in the bottom and wasn't providing the necessary vacuum for the EGR to open. make sure you check yours...

ymeski56

Anything effecting Vac will effect EGR function. You weren't getting idle surge?