Codes 311, 314 throwing a C/E Light

Austin112701

New Member
Mar 23, 2021
6
0
1
19
Indiana
Removed smog pump, now car is throwing codes 311 and 314. Also check engine lights on and aggressively blinking at me :) any help would be greatly appreciated
 
  • Sponsors(?)


Chythar

Recently finished repairing my rear
15 Year Member
Aug 26, 2004
2,310
93
98
50
West Los Angeles, CA
311 and 314 came up because you removed the smog pump, so air isn't getting pumped past some of the emissions controls. To permanently get rid of those codes, you'll need to get a chip for the engine computer that eliminates those checks. There are some other DIY ways of eliminating the codes, but I don't know them offhand.

When you removed the smog pump, did you remove anything else? Did you yank against any of the plug wires, or maybe smack a wrench into one of the spark plugs? That's one reason why Mustang5L5 said to check them. If you can't find anything, I'd recommend putting the smog pump back on temporarily and see if anything changes.Maybe another code will pop up once the 311 and 314 clear.
 

Austin112701

New Member
Mar 23, 2021
6
0
1
19
Indiana
311 and 314 came up because you removed the smog pump, so air isn't getting pumped past some of the emissions controls. To permanently get rid of those codes, you'll need to get a chip for the engine computer that eliminates those checks. There are some other DIY ways of eliminating the codes, but I don't know them offhand.

When you removed the smog pump, did you remove anything else? Did you yank against any of the plug wires, or maybe smack a wrench into one of the spark plugs? That's one reason why Mustang5L5 said to check them. If you can't find anything, I'd recommend putting the smog pump back on temporarily and see if anything changes.Maybe another code will pop up once the 311 and 314 clear.
I removed the line to the back of the heads, cut and flipped the connections to seal said heads, would this cause similar issues if I didn’t seal the heads properly? plugged a green vacuum line that runs to the tab/tad. I also figured that’s why those codes were being thrown(just didn’t know if anyone would have advice)
 

Chythar

Recently finished repairing my rear
15 Year Member
Aug 26, 2004
2,310
93
98
50
West Los Angeles, CA
The smog pump supplies oxygen to the catalytic converters; through the head when the engine is cold, and directly to the exhaust when warm. Here's a great post from jrichker that explains it better then I can:


If the plugs on the back of the head aren't sealed and are letting in unmetered air, it shouldn't affect the spark plugs but the O2's might see the exhaust as lean and cause the computer to add too much fuel to richen it back up.

The green plastic hose is from a different system, and hooks up to the EGR. That would be a different issue. The red hose supplies engine vacuum to the rest of the emissions parts, including the EGR. If you've got a broken hose (the plastic gets really brittle with age), that's more unmetered air in the system. Unhook the red hose from the intake and cap the nipple off, and see if that changes things.

A general bit of knowledge on 90's era Fords - The computer can adapt fuel flow to hide some issues, and sensors can report wrong values instead of failing outright. So it's rare to point to one thing that's causing all of your issues. It's likely several smaller issues combined together. This is why most help here will be of the type "try this, and report back your results". And this is with a stock system, which you've modified by removing the thermactor system. That's not necessarily a bad thing, but it can make diagnosis more difficult.
 
  • Useful
Reactions: 1 user

Austin112701

New Member
Mar 23, 2021
6
0
1
19
Indiana
The smog pump supplies oxygen to the catalytic converters; through the head when the engine is cold, and directly to the exhaust when warm. Here's a great post from jrichker that explains it better then I can:


If the plugs on the back of the head aren't sealed and are letting in unmetered air, it shouldn't affect the spark plugs but the O2's might see the exhaust as lean and cause the computer to add too much fuel to richen it back up.

The green plastic hose is from a different system, and hooks up to the EGR. That would be a different issue. The red hose supplies engine vacuum to the rest of the emissions parts, including the EGR. If you've got a broken hose (the plastic gets really brittle with age), that's more unmetered air in the system. Unhook the red hose from the intake and cap the nipple off, and see if that changes things.

A general bit of knowledge on 90's era Fords - The computer can adapt fuel flow to hide some issues, and sensors can report wrong values instead of failing outright. So it's rare to point to one thing that's causing all of your issues. It's likely several smaller issues combined together. This is why most help here will be of the type "try this, and report back your results". And this is with a stock system, which you've modified by removing the thermactor system. That's not necessarily a bad thing, but it can make diagnosis more difficult.
Thank you so much with your response sir! It gives me a lot to think about... I sadly won’t have time till this weekend to check things out, but will report back with any info I can provide! Thank you so much for your time
 

rockyracoon

10 Year Member
Nov 23, 2005
820
23
39
margate NJ
I've got 311 and 314 since I have the thermactor system partially disabled. I'm still running air to the cats but not to the back of the heads as my heads are not drilled for the passages. My 311 and 314 codes are present but do not illuminate the light. Are you sure there isn't another code present ?