Topic: running rich

[WranglerCOdy]

well i hooked my wideband because i have plans of boosting the jeep. and what i came to find is my jeep is running rich.  about 13.1 at idle, and about 10.9 to 10.0 under acceleration what can i do to fix this. or is it normal???

mods i have done:

40mm throttle body
throttle body spacer
cold air intake
flowmaster exaust
blown out cat converter( soon to be replaced )

can i use therichness to my advantage and run a hotter spark with MSD coil, 8 MM wires and iridium plugs?

i want more performance so anything helps.

thanks fellow fourbangers!!!

[sharpxmen]

is it TBI or MPFI?

well i hooked my wideband because i have plans of boosting the jeep. and what i came to find is my jeep is running rich.  about 13.1 at idle, and about 10.9 to 10.0 under acceleration what can i do to fix this. or is it normal???
[...]
blown out cat converter( soon to be replaced )

it isn't normal, you should be at 14.7

O2 sensor is the culprit usually, unless your cat is plugged (not sure what you meant by blown out, but if you didn't mean gutted i would start by replacing it first)

do you have a CEL? you should if it runs that rich. If not are you positive the wideband is installed correctly? a bad ground could give you false readings.

40mm throttle body

do you mean 4.0L or 60mm? unless it's TBI 40mm is small.

can i use therichness to my advantage and run a hotter spark with MSD coil, 8 MM wires and iridium plugs?

not really unless you have misfires in which case you should fix the problem. 10 is way too rich anyway unless you run some crazy amount of boost, regardless of the coil you'd not be able to burn all that fuel, but you should have black smoke coming out for 10:1 AFR so if you don't i would double check the wideband first.

[chardrc]

looking at his build thread he has a mpfi with a 4.0l throttlebody. should have cel at that richness as sharp said

[Torch_Ind]

first check fuel pressure.

other wise 02 sensor could be at fault. obd system won't flag a code for rich only if the o2 sensor is out of prescribed range. if your o2 sensor is stuck saying lean your comp will just add more fuel to the mixture.

the reason I say check the fuel pressure is I have bent my rear tank skid plate on my yj and it actually blocked the return line against the bottom of the tank causing me to run max fuel pump pressures.. was really really really hard on fuel and I blew my full filter rubber hose twice before I figured out I was running roughly 85psi.  also It did not flag any cel or dtc's computer just leaned out the mixture as much as it could.

[sharpxmen]

other wise 02 sensor could be at fault. obd system won't flag a code for rich only if the o2 sensor is out of prescribed range. if your o2 sensor is stuck saying lean your comp will just add more fuel to the mixture.

51    A lean air/fuel mixture has been indicated by an abnormally rich correction factor.
52    A rich air/fuel mixture has been indicated by an abnormally rich correction factor.

from FAQ (52 i think should say "lean correction factor"), never seen it on mine but never had 10:1 AFR either. 13:1 is probably not abnormally rich (or maybe not rich enough to throw a code) and if 10:1 is at wot then won't throw a CEL

if the O2 is faulty but not dead or if there's a bad ground along the way giving bad info to the PCM then it won't cause a code.

at 85psi you should have had a code, could be that some codes were available on later models and not early ones, the firmware has changed over the years (91-95) so that can be the reason you didn't get one (not sure what year is yours).

[Torch_Ind]

if the O2 is faulty but not dead or if there's a bad ground along the way giving bad info to the PCM then it won't cause a code.

at 85psi you should have had a code, could be that some codes were available on later models and not early ones, the firmware has changed over the years (91-95) so that can be the reason you didn't get one (not sure what year is yours).

mine is 1995 think it would have the best codes available just saying it never flagged a thing when I had the fuel pressure problem. I just had really bad fuel econo and keep blowing lines so I was playing with it to fix it cause didn't want a fuel leak. I also may not have driven it enough to get a code due to it keep blowing lines lol and I would try to repair. when I had the fuel leak that would have dropped my fuel pressure also not flagging a code.

and I have had the 02 do that before cause it wasn't reading it was just stuck giving the pcm bad info.

also for the time it takes to put a fuel pressure tester on the rail it's worth checking

[sharpxmen]

mine is 1995 think it would have the best codes available just saying it never flagged a thing when I had the fuel pressure problem. I just had really bad fuel econo and keep blowing lines so I was playing with it to fix it cause didn't want a fuel leak. I also may not have driven it enough to get a code due to it keep blowing lines lol and I would try to repair. when I had the fuel leak that would have dropped my fuel pressure also not flagging a code.

and I have had the 02 do that before cause it wasn't reading it was just stuck giving the pcm bad info.

also for the time it takes to put a fuel pressure tester on the rail it's worth checking

i had the same issue with the return but it was never that high, something more like 50 psi which is not that much, but like i said it didn't throw a code and my AFR was fine.

i would think (but this is just logic and can't confirm it first hand) that if you run rich enough that the PCM can't correct to 14.7 is when you'd actually get a CEL on the YJ PCM (obdII are smarter though), there is a point where the duty cycle is no longer being able to go low enough to correct for the too much fuel - in his case my guess is the o2 signal is off or his wideband doesn't read correctly.

[bukdwn]

I also had the same problem with a clogged fuel return line.    Very small dent in the tank skid.   85 psi of pressure with the FPR hooked up.  The dent must of been in the perfect spot because it was preety small dent.  Blowing the line at the fuel filter several times.  For me!  Instead of buying a skid plate,  I will Fab up one out of 3/16" .

[Torch_Ind]

I also had the same problem with a clogged fuel return line.    Very small dent in the tank skid.   85 psi of pressure with the FPR hooked up.  The dent must of been in the perfect spot because it was preety small dent.  Blowing the line at the fuel filter several times.  For me!  Instead of buying a skid plate,  I will Fab up one out of 3/16" .

I dropped my tank and shortened the return line so it doesn't touch the bottom of the tank

I did hit roughly 80's psi range as well

[WranglerCOdy]

 MY cat is hollowed out. I'm putting one back in when I have time and money. And I know for a fact my wideband isnt hooked up in correctly. Oringinal  o 2 sensor maybe ill pick one up today. But the ideas coming thanks guys.

[WranglerCOdy]

Well since I work at advance I got my O2 sensor ill Prolly put it in tomorrow

[Torch_Ind]

Well since I work at advance I got my O2 sensor ill Prolly put it in tomorrow

 

[sharpxmen]

Well since I work at advance I got my O2 sensor ill Prolly put it in tomorrow

reset the 'puter once you swap it.

[WranglerCOdy]

reset the 'puter once you swap it.

i disconnected the battery and swapped it tonight. noticed a little bit of difference but not alot. still drops to 10.9 on my gauge. 

im gonna get a cat this week and see if maybe that will help., i dont see how that will effect it but we will see

[Torch_Ind]

i disconnected the battery and swapped it tonight. noticed a little bit of difference but not alot. still drops to 10.9 on my gauge.  

im gonna get a cat this week and see if maybe that will help., i dont see how that will effect it but we will see

check fuel pressure and plug gab before you go to far.

also let the pcm learn it self for a bit