Topic: help i'm running rich

[leorn]

I have read the how to pass smog sticky, and several threads about rich fuel mixtures over the last year, but nothing sounded right, so here goes...
I've been putting the bandaid on the rich fuel mixture in my truck long enough!  Here's all of the info. 
Emissions:HC 120, CO% 1.68 at 2500rpm (should be 120 and 1.2 respectively for NV)
              HC 378, CO% 1.03 at 1600 rpm (same limits as above)
My idle always goes high.  I turn down the idle screw and the computer compensates it back up.
Timing:  I know it is advanced.  Not sure how much, but I put it where it runs best.
K&N conne filter
lc engineering header
20,000 on the fresh 22re.  aftermarket, stock specs. (the engine didn't pass last year either until a mechanic played with it to get it to pass.)
modified MAF to three teeth rich.  This actually got rid of the small stutter the engine used to have.
functioning stock thermostat.
being that it runs rich it burns up plugs, but I replace them fairly often.
I get 15mpg best case.  this truck used to get 20 with the old engine.

I don't know if I have something that is bad, or if I don't have a sensor hooked up.

What do you guys recommend?

[Hottrod81]

Sounds like it might be an O2 sensor.  I would also try timing it with a light.

[leorn [OP]]

oh yeah last year the mechanic replaced the o2 sensor.  but they only did all of the bandaid fixes to get it to pass...ie retard timing, fuel additive, who knows, but that was the only part replaced.  Need to check the timing light.  but I need to learn where to short circuit so that I can actually read it.

[BigMike]

What head gasket are you using? Is it of an OEM thickness? Do you have an adjustable timing gear? What kind of muffler are you running?

It could be that your cam timing is off, and that combined with the freeflow header and a freeflow exhaust, it could very easily be blowing out raw fuel during the end of the exhaust and at the begining of the intake stroke if the valve timing is advanced enough, which would also explain why it has a rough idle.

How tight are your intake valves? What cam are you running?

[leorn [OP]]

What head gasket are you using? Is it of an OEM thickness?

  not sure.  I'm assuming stock thickness as I ordered a complete new engine and asked that it be as close as possible to an exact replica of what the truck originally came with. 

Do you have an adjustable timing gear?

no

What kind of muffler are you running?

magnaflow.  2 1/4" all the way back.  high flow cat, not sure what kind

It could be that your cam timing is off, and that combined with the freeflow header and a freeflow exhaust, it could very easily be blowing out raw fuel during the end of the exhaust and at the begining of the intake stroke if the valve timing is advanced enough, which would also explain why it has a rough idle.

Idle is really smooth actually, but again I have to advance the timing and turn the maf 3 notches rich to achieve this.  Idles at ~1600 according to the smog guy.  Like I said when I turn it down the computer compensates and brings it back up.

How tight are your intake valves? What cam are you running?

stock cam.  valves should be set to stock.  I know exacltly what it sounds like when they get loose.  It would be good to check though.  That's gonna have to wait a couple of weeks with the holidays.

Do I need to change the stock cam out???  I am thinking you are on the right track as I believe it has run rich since I put on the header...but that was three years ago and it didn't require a smog where I was living.

[leorn [OP]]

I had to get it into the shop since it expires soon, and I don't want to spend 20 bucks a shot just to tweek something...test...fail...tweek something else...you get the idea.  Shop hasn't been able to get it yet.

I also call lcengineering to ask if it the header might cause the engine to run rich.  They said it shouldn't affect the fuel mixture, but I am not convinced that is the case. 

Anyways, if one of ya'll don't have any ideas, I am gonna put on the old flame suit and post up on Pirate.