car running rich

[89supra7mgte]

My car seems to be running really rich and i have no aftermarket mods except bov(atmosphere vent). What will cause this? i have checked for vac leaks and boost leaks none found, fixed what i did have.

The fuel system is stock. Can the wrong spark plugs cause this? i have no running issues at all. and no codes

 

[jessemkiiis]

"bov(atmosphere vent)" somebody correct me if im wrong but wont this cause rich conditions? ecu's pumping gas for air thats not going in the intake.
I would try recirculating that bov...

 

[dusthead]

i was running really rich and actually failed my emissions test...due to a broken wire going to my o2 sensor. (hopefully only that........lol)

 

[89supra7mgte]

Yes the bov does cause a rich condition when it opens up, so i have been told on here. I do get a little backfire everynow and then from that. I can live with this, only cause i dont need to boost all the time.

The condition i am having now is that it runs rich all the time. NO smoke but you can smell the fuel at the exhaust. I filled the car up(91 octane), got maybe 80 miles on it since the new head gasket and i am down half a tank already.

I know the car previously had a bad afm fixed that, that actually caused the car to smoke from so much fuel. And before all my work was started i inspected the exhaust, both cats plugged beyond belief (hollowed out now), maybe from bad afm? Could this have taken out my o2 sensor as well? I am not gettin any codes for it though? Ill look on the tsrm and see the specs on testing it.

Anyone got any other ideas let me know. BTW i have absolutely no running problems with this car, just burns fuel and stinks.

 

[jessemkiiis]

I would check for a small boost leak, even a small crack could throw you AFR off.
have you checked timing, plugs?

 

[Another MkIII]

I would check for a small boost leak, even a small crack could throw you AFR off.
have you checked timing, plugs?

+ 1 on Timing, that could cause it.

An intake leak could cause you to be rich IF you were in boost, in vacuum, it would cause a lean condition, but that can cause a lean misfire and high HC's, O2, and NOX

If you were rich, you would have elevated HC's, high CO, lowered CO2, low O2, and low NOX

You don't have access to 5-gas readings from your emissions by chance do you?
-AM3

 

[jdub]

You should check your ECU codes.

 

[Boostedmkiii]

You should check your ECU codes.

+1

It sounds like a bad knock sensor(s) to me... Or a boost leak.

 

[BOOSTEDSUPRA]

+1

It sounds like a bad knock sensor(s) to me... Or a boost leak.

:word8kn:

 

[89supra7mgte]

Ill check codes again did not have any prior.

sprayed intake manifold areas with aero start (IJ) found no change in rpm, so i would assume no leaks. will check again though

When set timing i jumped pins set at 10* pulled jumper it backed down to 8? I am at higher elevation so should a set base a little bit higher?

Have not pulled plugs to recheck, they are the oem reccomended plugs. Should i try a different plug? I read on here that the autolite 3923(i think that is the correct number) are a good choice any word on that or reccomendations?

I can run it on a 5 gas here at work, Colorado does not have emission requirements so i am not sure if they will be able to check that at this time.

 

[89supra7mgte]

OK so i have no codes still. Gonna test my 02 when i get the driveline re installed, but i have one problem i cant find a replacement anywhere.

Are there any other alternatives? i plan to go to wideband in the future when i start gettin more into the tuning, as of right now i have not.

I found multiple o2 sensors but they are all one wire, even the ones that say pre cat? some with the oe adapter as well.

any suggestions? How would a wide band hook up to the ecu or does it not? and if i were to get a universal o2 (prefer not to right now, only because of adding the o2 hole) how would it hook to original harness?

Please help, and once again i do not need it at this time just wanna no what my options are in case i do need one.




BTW: The egr system has been deleted by the previous owner, can this affect the running rich?

 

[dusthead]

lots of part-outs goin on...a cheap o2 sensor swap couldn't hurt....not sure if i have one...but check the FS area.

 

[89supra7mgte]

cool thanks

 

[89supra7mgte]

I had a car come in today (at work) it was running rich and filling up the charcoal canister with fuel. Very different from my car, other than running rich. I started thinking, my charcoal canister has no vacuum to it (all evap/egr vac lines deleted by po) so i was wondering if this can be having an affect on my system? Maybe by not purging the tank properly the rich fuel smell from "exhaust" is actually seaping from tank?

I am going to run the cc vac lines how they should go through the bvsv and to tb. I am still at a loss on this one.

Also had ideas of o2 sensor being fucked up just enough to create a false reading to ecu but not enough to set code?

gonna pull plugs and check to see what they look like tomorrow as well. They are the oe rec but heard ups and downs on these. any plug recommendations?

 

[Victor Charlie]

I had a car come in today (at work) it was running rich and filling up the charcoal canister with fuel. Very

I'm in the same place with mine. No boost leak, runs rich, no codes, otherwise drives well, except a funny rpm variation in a narrow band with no load.

to test the O2 sensor, I ordered a Zietronic wideband setup, which is essential anyway, and will monitor TPS I'm looking also at swapping AFM. in theory, high fuel pressure might do it. i have only the stock FPR. It would be interesting to know how your A/f mix changes under different speeds, load, ambient conditions, etc. I also wonder if the altitude sensor is ever an issue, i haven't thought about it up to now. Let me know if you think of anything else outside of spark issues, which is no longer my problem.

good luck.

 

[MKIIISupraGuy]

I would like to know what kind of plugs are in there when you pull them out...

My Supra was doing the same thing when I first got it. Ran fine, boosted fine, but smelled to high heaven of fuel, and timing was dead-on.The seller told me the plugs were fresh OEM recommended Bosch....and had about 3k miles on them. Well I did'nt trust those words, and started researching. I found out the recommended plugs are actually NGK,(look at the TSRM if ya want: click here so I bought NGK plugs/wires. Once I had them installed I fired her up and DAM what a difference !!! Smooth idle, fuel-smell gone, and mpg went way up.

 

[89supra7mgte]

I just swapped out my ngk plugs (that i was told were oem ngk bcpr6egp), believe they are platinums, for another set of non plat ngks and still have bad fuel smell, no change. Drives just as good as it did before too. The old plugs are not fuel fouled or anything. still look brand new. No boost leaks just went through entire system.

I have a stock fpr, lex (have 3 others as well) aftermarket bov, other than that it is all stock. and poor gas mileage.

I read that the lex afm without 550s will cause car to be lean? well i have no wideband to verify, but i can smell it any more ideas? BTW no codes either.

these are the part numbers i got for the afms maybe you guys can help decipher?
1. "Lex afm" ls400 was told 22204-42011 fmz3ayy2
2. "lex afm" sc400 " "
3. junkyard afm i pulled off sc300 22204-42011 fmz3ayy2
4. Afm originally on car 22204-42010 fmz3ayy1

 

[suprajztwenty]

same prob here, no faults...not uber rich, but the stink and bad mileage is there. even without boosting i think the best i got was 18. im going to take a long trip tomorrow so ill see what all highway does.

quick question, the ecu temp sensor, the base is cracked but the terminals still seem to be ok. would it cause a check engine light? what about an o2 sensor fault, knock sensor and all those others that cause a rich condition...will some NOT throw a fault?

if some wont throw a fault, whats my next step? just ohm out each sensor and trace the entire harness...doesnt sound like fun...better than pulling the oil pan...but still no fun

really your stink is mostly because of gutted cats, but i really wanna figure out whats going on

 

[Victor Charlie]

same prob here, no faults...not uber rich, but the stink and bad mileage is there. even without boosting i think the best i got was 18. im going to take a long trip tomorrow so ill see what all highway does.

quick question, the ecu temp sensor, the base is cracked but the terminals still seem to be ok. would it cause a check engine light? what about an o2 sensor fault, knock sensor and all those others that cause a rich condition...will some NOT throw a fault?

if some wont throw a fault, whats my next step? just ohm out each sensor and trace the entire harness...doesnt sound like fun...better than pulling the oil pan...but still no fun

really your stink is mostly because of gutted cats, but i really wanna figure out whats going on

I think the general opinion tends to be: 1) check your codes if you have and engine light, check even if you don't. It's so quick and easy, you could almost do it at a traffic light and be off before the light changes.
2) consider the cost of a wideband O2 sensor. It's about the same as replacing the stock sensor, or having a shop check your car and give an estimate, etc. It's worth the money ten times over. I believe the answer to your first two questions is yes.
3)you might need a separate thread if you want to get more specific trouble shooting help on your particular situation.

 

[Victor Charlie]

same prob here, no faults...not uber rich, but the stink and bad mileage is there. even without boosting i think the best i got was 18. im going to take a long trip tomorrow so ill see what all highway does.

quick question, the ecu temp sensor, the base is cracked but the terminals still seem to be ok. would it cause a check engine light? what about an o2 sensor fault, knock sensor and all those others that cause a rich condition...will some NOT throw a fault?

if some wont throw a fault, whats my next step? just ohm out each sensor and trace the entire harness...doesnt sound like fun...better than pulling the oil pan...but still no fun

really your stink is mostly because of gutted cats, but i really wanna figure out whats going on

I think the general opinion tends to be: 1) check your codes if you have and engine light, check even if you don't. It's so quick and easy, you could almost do it at a traffic light and be off before the light changes.
2) consider the cost of a wideband O2 sensor. It's about the same as replacing the stock sensor, or having a shop check your car and give an estimate, etc. It's worth the money ten times over. I believe the answer to your first two questions is yes.
3)you might need a separate thread if you want to get more specific trouble shooting help on your particular situation.