Cylinders #1,3,5 running rich

[bentandbuzzin]

My z is running really rich and i mean rich. So rich the fumes burns my eyes and my clothes smell like i was inside the exhaust pipe. The car will idle rough but will eventually die. Sometimes its hard to start and needs some help with the gas pedal. I pulled the plugs and they are not covered with gas but cyl #1,3,5 are really black. When i get the car started it will idle ok for a few minutes with no fuel smell from the exhaust but after that the idle drops and the fumes appear. I did the o2 check with the ecu and the left side o2 blinks but once every 10 sec. Then when i switch to the right side it doesn't blink at all. I think they are supposed to blink 5 times every 10 sec. So i'm guessing i need o2 sensors am i right? Any help or ideas will be great.

[DanDrath]

sounds exactly like the problem i had, bad o2 sensor will 100 Percent do that. Your lucky the passenger side is bad and not the drivers(pass side is much easier to get to). Try unplugging it and see how the car runs.

[bentandbuzzin]

when i bought this car the previous owner had hacked the signal wire to run a air/fuel ratio gauge. The car was running rich then but it also had a head gasket leak. I couldn't tell how rich it was running because all i could smell was the antifreeze in the exhaust. So i butt connected the wire back together to see if it would work but i guess it didn't. I got aftermarket headers on right now and it was very easy to get to the sensors because they face forward toward the wheels. If i unplug the sensor what should the car do?

[DanDrath]

it will run off the ecus programed a/f ratio. When my o2 was bad my car actually ran better with the o2 unplugged then with it plugged in

[bentandbuzzin]

Ok i'll try that and let you know what happens. Thanks.

[Blurr]

Bent sounds like the same problem I have. Let me know what your remedy is cause I think Ill follow suit on repairs...

[bentandbuzzin]

Well.. i unplugged the o2 sensors and it didn't change to much. I'm still going to replace the o2 sensors because when i did the diagnostic with the ecu they didn't respond like they should've. I wonder if my headers could make the engine run rich. I opened the idle valve quite a bit, adjusted the timing some. After all that the smoking stopped but still has rich smell in the exhaust. No fuel on the plugs. I replaced the PTU and it starts better now. I'm still running bosch platinum plugs and i'm sure when i change those to NGK the richness should diminish. If the plugs don't solve the problem i will be out of options. I got to figure this out because when i tag this car i will have to get the emissions done soon after.

[bentandbuzzin]

Bent sounds like the same problem I have. Let me know what your remedy is cause I think Ill follow suit on repairs...

Well.. i unplugged the o2 sensors and it didn't change to much. I'm still going to replace the o2 sensors because when i did the diagnostic with the ecu they didn't respond like they should've. I wonder if my headers could make the engine run rich. I opened the idle valve quite a bit, adjusted the timing some. After all that the smoking stopped but still has rich smell in the exhaust. No fuel on the plugs. I replaced the PTU and it starts better now. I'm still running bosch platinum plugs and i'm sure when i change those to NGK the richness should diminish. If the plugs don't solve the problem i will be out of options. I got to figure this out because when i tag this car i will have to get the emissions done soon after.

[Oh Em Zee]

#1,3,5 rich = one side of engine = one side of headers = 1 o2 sensor.

[evildky]

cat might be dead on that side

[E_Cruz1989]

I kind of have the same problem on my Z, for those of you who haven't been following along, I have some possessed fuel injectors, but the other day I checked my plugs and cylinders 1-3 were RICH and 4-6 were LEAN. Ya know what I mean son?!

[Oh Em Zee]

i'm unsure for your situation E_Cruz1989, it seems odd that you would get lean on one side, rich on the other, because O2 sensors dont go bad that often it seems (for there to be two bad O2 sensors. just think of all the things that effect fuel delivery, and why the ecu would send either too much fuel to 1-3-5 to compensate for 2-4-6. the best advice i can safely give because of my inexperience, is to check the wiring on your o2 sensors, make sure your exhaust is bolted up properly from the headers back if you have the access, because it's not too hard to do and it's free, vs paying a few hundred for fuel injectors before knowing that's your problem.

it's really unlikely you are having problems with your fuel injectors being that it's practically all cylinders. if one goes bad however, the others on that side of the engine quickly follow.

[bentandbuzzin]

#1,3,5 rich = one side of engine = one side of headers = 1 o2 sensor.

I'm thinking that might be it because when i bought the car the last owner had hacked the o2 sensor to connect to a air/fuel gauge. I connected the ends back together but i guess its still having issues.

[bentandbuzzin]

cat might be dead on that side

Any way to test the cat?

[Oh Em Zee]

hacked wiring is usually the leading cause to problems. a dead cat, i'm guessing means it's been clogged with oil and restricted airflow. you would tell the difference in the sound of the car usually. i'm unsure on what other common problems occur with the cats.

[evildky]

a working cat should be very very hot, if the issue is only on 1 bank then compare the temps of the 2 cats, if the non rich side is hotter than the rich side then you found the problem if they are about the same or the rich side is hotter you continue troubleshooting

[E_Cruz1989]

i'm unsure for your situation E_Cruz1989, it seems odd that you would get lean on one side, rich on the other, because O2 sensors dont go bad that often it seems (for there to be two bad O2 sensors. just think of all the things that effect fuel delivery, and why the ecu would send either too much fuel to 1-3-5 to compensate for 2-4-6. the best advice i can safely give because of my inexperience, is to check the wiring on your o2 sensors, make sure your exhaust is bolted up properly from the headers back if you have the access, because it's not too hard to do and it's free, vs paying a few hundred for fuel injectors before knowing that's your problem.

it's really unlikely you are having problems with your fuel injectors being that it's practically all cylinders. if one goes bad however, the others on that side of the engine quickly follow.

Thank you for your response. Looks like I will be checking my o2 sensors and exhaust installation before I put in my new plugs and just fry those as well.

[bentandbuzzin]

a working cat should be very very hot, if the issue is only on 1 bank then compare the temps of the 2 cats, if the non rich side is hotter than the rich side then you found the problem if they are about the same or the rich side is hotter you continue troubleshooting

Thanks. I'll get a temp gauge and see what's up.

[evildky]

not a temp gauge, a lazer or infared thermometer

[bentandbuzzin]

Bent sounds like the same problem I have. Let me know what your remedy is cause I think Ill follow suit on repairs...

I changed my plugs to the required oem ngk PFR6B-11, 6G-11, 5B-11plugs and it reduced the rich smell a bit. Then i adjusted the idle to 850 rpm but i'm still trying to get it to go 750rpm. That reduced the smoking from the tail. A friend gave me some valvoline fuel system cleaner and i put that in on a low tank. I let it run for a while until it was almost empty and then put in about 1/4 tank of 89 octane gas. I then took the car for a drive until the tank was almost empty again. Then i put in another 1/4 tank of 93 octane gas and drove out on the highway for about 15-30 min. When i returned to my garage the rich smell was gone and the exhaust smelled like it should. I guess an injector may have been dirty or the converter may have gotten cleaned by the fuel treatment. Thats what i did but i'm not sure it this will fix your issue but you can try.

[Blurr]

I think Ill try this. I ordered a new set of injectors. the ones that are currently in mine are 550 cc ones which is probably f*** everything up as far as mine running rich. also im going to return my safc to factory presets, or remove it completely before i take it to the shop.

checked my oil and had a mechanic help me take a look at it yesterday, bummed its so dirty, ll prolly do the plenum pull, delete some of those hoses, and replace both valve cover gasket seals, and intake seal.

its a shame that the guys who had this before me kept the z in this condition.

On a forum i used to frequent back in the day, we had group buys with members who had similar problems. I wouldnt mind getting something going if some of you are down.

[Blurr]

and i found out what that fuel smell was when i drive the car. when he replaced the fuel filter he put it in BACKWARDs, and when you start the car, one of the clamps wasnt tighened, so when drive it fuel squirted out. f*** RETARDED. inspected the hoses and lines, and none are cracked. Idled before i drained the oil, The Fuel smell was gone.

[E_Cruz1989]

Don't mean to thread jack OP, but my thread barely gets read anymore lol, I replaced my spark plugs and o2 sensors, and I'm still feeling misfire, where should I check next? The misfire is only during idle, under normal driving conditions the car drives as it should and has the power.

[bentandbuzzin]

not a temp gauge, a lazer or infared thermometer

I knew it was something else and not a temp gauge. Thanks for making that clear.

[bentandbuzzin]

Don't mean to thread jack OP, but my thread barely gets read anymore lol, I replaced my spark plugs and o2 sensors, and I'm still feeling misfire, where should I check next? The misfire is only during idle, under normal driving conditions the car drives as it should and has the power.

Before i changed my plugs my z idled like crap. I found that 4 of my coilpacks were split open. My friend found out the hard way which ones were bad. They were split at the top just under where the mounting holes are.