FPM???

[NotoriousGT350]

Been over a month since I've started the cobra and still trying to diagnose the problem with it idling rich. When I connected the old Predator Programmer and ran the Gas/Fuel datalog, I noticed "FPM" was going on and off. I've already changed out the FRPS, spark plugs, and checking vacuum fittings and can't find the issue.

Now is the FPM indicating the module? Just trying to pin point all this. I know it could be a vac hose under the intake is another place to look, but just checking off a couple things first before I go start digging.

 

[03cobra#2]

It looks like you are in closed loop, which means the ECU should be using the front O2's to maintain 14.7. How do you know you are running rich? Do you have a wideband installed?

 

[NotoriousGT350]

AFR on wideband at 12-13 idling. I just have the front O2s since I have an o/r Prochamber midpipe. If I'm cruising in 4th for example, it will maintain at 14.7. Once I come to a light or just idle, it drops to 12:1 for the most part. Starts and smokes a little which I can really smell the exhaust fumes.

Thinking maybe a bad O2??

 

[03cobra#2]

Might not

AFR on wideband at 12-13 idling. I just have the front O2s since I have an o/r Prochamber midpipe. If I'm cruising in 4th for example, it will maintain at 14.7. Once I come to a light or just idle, it drops to 12:1 for the most part. Starts and smokes a little which I can really smell the exhaust fumes.

Thinking maybe a bad O2??

It's possible. If they are older, it's good to replace them anyway. Might not be a bad idea to datalog the short term fuel trims to see what they are doing. I don't know how you would do that with a old predator tuner though.

Also after the car is fully warm, and it sits and idles for say 2 minutes without pressing on the gas pedal, is the wideband still showing 12-13? Or does it eventually return to 14-15?

 

[NotoriousGT350]

I'll just go ahead and replace them then and see what happens. I can monitor Long and Short fuel trims. After it warms up to operating temp, it still runs rich. Sometimes under 12.

 

[NotoriousGT350]

I remember my LTFTs were -25% and STFTs were 25%

 

[NotoriousGT350]

*UPDATE*
Replace both upstream sensors and still running rich. I have some pictures listed below I’m different modes after the car has warmed up in idled.

GAS DRIVABILITY

 

[NotoriousGT350]

*GAS IGNITION*

 

[NotoriousGT350]

*GAS FUEL*

What is “LOW PSP”??

 

[01yellercobra]

Do you have access to a scanner that gives normal codes?

 

[NotoriousGT350]

I do not. I may check with a buddy to see if he can get a tech at a dealership just to scan.

 

[NotoriousGT350]

Maybe I need to take the injectors out and test them. I don’t know, and running out of options. If I’m cruising in 4th for example at 2000rpm, the AFR holds at 14.5:1, but drops to 12:1 once I let off the gas or if I slow down.

 

[01yellercobra]

Maybe I need to take the injectors out and test them. I don’t know, and running out of options. If I’m cruising in 4th for example at 2000rpm, the AFR holds at 14.5:1, but drops to 12:1 once I let off the gas or if I slow down.

That would be the tune. Mine does the same thing. But I haven't finished dialing things in yet. The big thing of that it comes back to the correct A/F after a couple seconds.

 

[DSG2003Mach1]

That would be the tune. Mine does the same thing. But I haven't finished dialing things in yet. The big thing of that it comes back to the correct A/F after a couple seconds.

agreed, not an injector issue

 

[NotoriousGT350]

Well, my tuner is no longer here. Why would my tune decide to take a shit after 10-12 years? Old??

 

[NotoriousGT350]

Is it possible my wideband commander sensor is just bad? I’m going to go ahead and change it out since I did the upstream sensors too.

 

[olympic]

Wideband sensors have short lifespans, some guys replace them every year. My last set lasted 3 years and maybe 6000 miles.

 

[01yellercobra]

Tunes don't go bad. Something mechanical probably wore out.