Rich Exhaust Smell

[Silver Fox]

Buick Brainiacs,

My 52,000 mile car (mods in sig) is just plain smelly to drive. It smells like it is running very rich, but my Scanmaster numbers look good (INTs/BLMs always right around 128 or working to get back to it from 126 to 131 or so) and fuel pressure is 43 psi line off.

The smell is bad enough I usually have to change clothes when I get home since my clothes smell of exhaust.

I just swapped out oxygen sensor and no change. Although when researching this topic, I noticed the O2 sensor I bought (Bosch) have been giving problems to some people. I have a heated O2 wiring harness sitting on my shelf. Does anyone know what sensor it takes so I can run down to Autozone to pick that one up and see it that helps.

I believe all my plugs look good, bit can yank a few out a post pics if someone believes that would be helpful.

There are no obvious exhaust leaks I can find.

Is there anything I am missing. I don't recall this with my stock 28 pound injectors. Could the 60 pounders be the cause of this?

I am not noticing any smoke (black, bluish, or otherwise) from the exhaust when I gas it.

Thanks for your help.

Rob

 

[mytoy]

Are you getting fuel in the oil. I had a injector stick open and it smelled strong.

Matt

 

[blackgn1]

Try a Denso 02 sensor. Do you have a fuel leak somewhere? I had leak at the regulator. Found it as soon as it started leaking because the smell of fuel was so strong.

 

[Silver Fox]

Are you getting fuel in the oil. I had a injector stick open and it smelled strong.

Matt

Matt - I will check this tomorrow, as well as seeing how long it takes my fuel pressure to drop off once I turn the car off. I will post the results of both findings.

Try a Denso 02 sensor. Do you have a fuel leak somewhere? I had leak at the regulator. Found it as soon as it started leaking because the smell of fuel was so strong.

blackgn1 - If the troubleshooting above doesn't indicate anything, I will order a Denso. I will check for fuel leaks tomorrow also and post back the results.

I appreciate the thoughts - does anyone have any others?

 

[jdpolzin]

What are your O2 reading under WOT? O2's at idle? If all seems good, you might be able to just take a little fuel out during idle.

 

[Silver Fox]

What are your O2 reading under WOT? O2's at idle? If all seems good, you might be able to just take a little fuel out during idle.

jdpolzin - good to hear from you. I'll call you tomorrow, plus post up the results here.

 

[turbo nasty]

Rob, Have you tried lowering/raising the fuel psi at idle and see if the chip adjusts accordingly?
Fuel psi 42 line off?

Have you reset the ECM lately?

How do the plugs look?


4 wire o2's that go with the Caspers Heated o2 kit

234-4018 Denso part #

21539 NGK

AFS 109 AC delco

 

[DailyDrifter]

Check the coolant temp sensor.

 

[Silver Fox]

Check the coolant temp sensor.

Dave - Scanmaster numbers look good for coolant (168-172 warmed up and driving it. Should indicate it is good, correct?

 

[Silver Fox]

Rob, Have you tried lowering/raising the fuel psi at idle and see if the chip adjusts accordingly?
Fuel psi 42 line off?

Have you reset the ECM lately?

How do the plugs look?


4 wire o2's that go with the Caspers Heated o2 kit

234-4018 Denso part #

21539 NGK

AFS 109 AC delco

Fuel pressure is either 42 or 43. I will look tomorrow to be sure.

ECM has been reset.

Plugs look good but I will pull them all out to see if any look different.

Thanks for the info on the O2 sensor numbers.

BTW - finally found that wiring harness for the heated O2 sensor we talked about....

 

[rmar]

I run a TT alky chip and it is very rich on start-up. I would ask Eric about it.
I'm sure it is that way for driveabitity issues.

 

[turbo nasty]

Fuel pressure is either 42 or 43. I will look tomorrow to be sure.

ECM has been reset.

Plugs look good but I will pull them all out to see if any look different.

Thanks for the info on the O2 sensor numbers.

BTW - finally found that wiring harness for the heated O2 sensor we talked about....

Lol glad you found it. Scratch that on the idle check I forgot the TT is open loop. Maybe use a very small screwdiver or something just to break idle (not 2 grand) and get the car in closed loop and then alter the fuel PSI to see the ecm change. The decimal on the SM should go solid as soon as idle is broke. If you have a fuel psi gauge mounted on your rail I would get another as the engine vibations can cause wrong readings over time. I say that but if your cruise BLM's are in check then that would rule out fuel psi being way off.
Post up some numbers.

By chance is the Cam sensor setting off?

 

[rmar]

Lol glad you found it. Scratch that on the idle check I forgot the TT is open loop. Maybe use a very small screwdiver or something just to break idle and get the car in closed loop and then alter the fuel PSI to see the ecm change. The decimal on the SM should go solid as soon as idle is broker a while. If you have a fuel psi gauge mounted on your rail I would get another as the engine vibations can cause wrong readings over time.

Dat be it..... What chip are u running???

 

[turbo nasty]

I have spoken with Rob about this and he is saying its stanky while driving it as well.

 

[rmar]

I would say E keeps the fuel cranked up on these out of the box.
It kida idiot proofs (the best ya can) them. If it was made for 25-28 psi
it is pretty much set dead red.....

 

[UncleDave]

I noticed this with the TT chip as well. I had smaller injectors with a non-alky chip, so I figured it may have been set rich as a precaution. I wondered why it would be that way at idle, though being open loop makes sense, and I'm sure another chip could be burned with a little idle fuel removed if necessary. Otherwise the thing ran like a champ. I'm also running no cat, not sure if that matters.

 

[87gninpa]

I have the same issue as well. Idle O2's are well over 800, but blm/int are both 128. Anything off idle and the O2/Int.BLM are all great. Does stink when its idling. I tried to take fuel out, which helped at idle a bit, but then it was lean while cruising.

 

[Silver Fox]

Okay,

Hopefully I can answer some of your questions and we can work from there.

1. The car had not been driven in 24 hours. I started it up just long enough check the fuel pressure with the vacuum line off. It was 42.5 pounds or so. My fuel pressure gauge is at least six years old - I am wondering if the calibration could be off.

2. I then pulled the plugs out. The spark plugs (pretty new/low mile) all looked like this:

Except this one (driver side rear most cylinder), which looked like this:

The threads were wet from fuel, and it smelled of fuel very bad. Electrode looked good though. Plug did not seem to be loose when I pulled it out.

3. I decided to check the resistance on the spark plug wires to see if the wire going to the wet plug was bad. They were all about 5 to 6 ohms, not much variation between any of them.

4. I checked the MAF translator to make sure all settings were correct for the 3 inch LT1 MAF. They were all set correctly, but I did change one of the settings to "Lean Idle" to see if that helps out.

5. Chip - TT Alky Chip for 60 pounders.

6. Oil "might" have a slight smell of fuel in it - not strong but perhaps a slight scent of fuel.

7. No fuel leaks that I can find.

8. I have not started the car back up - waiting to see how long it takes for the fuel pressure to drop off. I shut the car off 2.5 hours ago. It was 31 psi when I shut it down. It is at 28 pounds right now.

9. Just to give you an idea of how rich the car is running, I lightly wiped a paper towel inside the exhaust pipe and here are the results:

Anyone have any new thoughts based on my findings thus far?

 

[turbo nasty]

Okay,


4. I checked the MAF translator to make sure all settings were correct for the 3 inch LT1 MAF. They were all set correctly, but I did change one of the settings to "Lean Idle" to see if that helps out.

:biggrin:

 

[Silver Fox]

:biggrin:

Yep - thanks TurboNasty. I will drive the car tomorrow and let you know if there is any difference.