Hello, Just had a issue out of the blue, The car all of a sudden seems sluggish, it has an occasional backfire, i was crusing around 35 and pushed the throttle down and the car laid over. I am wondering if cold weather starting could foul the plugs, There are no dtc codes thrown, although the left o2 sensor does not cycle like it should, it stays up around 800-900 range, the right one cycles between 300-900, could the o2 sensor cause this type of problems

 

Sounds like it is running uncontrably rich for some reason. Maybe it's the sensor. You could always switch sides and see if it follows the sensor.

 

I had problems with plug fowl and cold outside temps @ start.
My app... 97ss 383 D1-14psi M6 72#injectors obd2 pcm.
I leaned out all the low temp open loop afr cals, and, changed the VE tables for 0 to 350 rpm range.
I was always fowling NGK plugs with a cold air start with the stock open loop stock settings.
I changed to Zex plugs, and, they tend not to fowl as easy.
I do not have a plug fowl problem unless there is an O2 failure or a voltage interrupt open-circuit on the injector power circuit, loss of bypass valve air when it has been measured by the MAF. B.

 

Thanks for the info, I scanned the car again today and the o2 sensors seem to be ok, maybe i just wasent reading it properly b4, but the car still isnt right, there are no codes, but the car sounds like its on 7 cylinders. It also surges a little, Its icy here now, sat i guess ill check the plugs

 

My experience has been similar (checking everything). The last thing I did was to pulll a plug. Large soot deposites and fluffy cake on the plug. Then you ask yourself why???

Some of my root cause problems were...
Fuel regulator leaking.
Bad injector 12vdc+ power.
Bad injector ground circuit.
Bad O2 sensor (I moved both of them).
Coolant temp sensor bad or disconnected.
Old MAP sensor (It tested bad cal).

I re-flashed the PCM with a lean of the open loop AFR tables. I noticed it would always start FAT with very cold weather during an initial cold start with large injectors. I cleaned the plugs and re-installed them. The single NGK electrode did this alot. One plug failure with the Zex plugs due to bad injector conductors. Plugs are not easy to change on the F_body.

The Zex plug has additional prongs that tend to clean the plug and prevent fowl (@ least that is what the MFG claims). At least, this has been my experience with FI applications (97ss 383 D1 M6 - 72# peak and hold injectors).

Hope this helps. B.

 

Ok, well ill have to check the regulator and the injector circuits. The car has a new temp sensor, map sensor, & from what ive seen the o2 sensors seem to be ok, Ill have to send my pcm somewhere to get it flashed, I am using autolite plugs right now, they were reccomended by the builder for the TFS heads, they are 1 step colder plugs, Maybe a colder plug is not a good idea in the winter months but like you said its such a pain in the *** to change the plugs in this car it not something you want to do all the time, I also think my FP is high, After i installed the racetronix kit my fp is around 44 to 49. I think that is high but since my aeromotive regulator took a **** ive had to use the stock regulator, but im waiting on warmer weather to do my fuel rails in parralel, I already have everything ready and ill be using a Magna fuel regulator

 

OK well i pulled a random plug today just to check it and good new /bad news.

The color of the insulator looks excellent, tan color looks good, but there is a hard buildup on the electrode and a little on the insulator, i can get it off but i would like to know what is causing this problem. These are autolite plugs # 3924 & they only have around 600 miles on them. Now granted that was only one plug. On sat im going to pull all 8 but i would like to correct the problem b4 i install new plugs.

 

Tan color is good on plug. I don't know about "hard coat" on insulator, but any short circuit of the plug will not allow combustion. May I suggest you purchase software to do your own PCM flash. I use LT1_edit version 2.2 for OBD2. I have tried mail order, and, I was never happy with the flash. My opinion is it is difficult to tune a FI application by mail. You are always making changes. I have hundreds of PCM flash program edits, and have loaded probably 30+ to the PCM over the years. Also, I had to purchase a DynoJet WB O2 sensor. Very difficult to tune a FI app without that tool. Make small changes to your program flash and learn.

I have also learned that any injector conductor resistance can cause a rich condition. If you use a digital meter on audible ring, do not trust the ring. Monitor the LED display for the speed of conduction as you ring each wire conductor. Your PCM fires injectors in milli-second time intervals.

My FI app experience... When you go blown, it changes everything from the PCM thru the drive line. It is quite an learning experience, and, I have had my share of failures and mistakes. But, good for the brain. Best of luck to you. B.

 

Well I got the plugs out of the car today, What a PITA, Thats the 2nd time ive done it and it didnt seem any easier this time, although i didnt drop the y pipe this time. Anyway the plugs look horrible, The car is obviously running rich and the cold weather starts dont help either, the plugs on the passenger side are black with a little buildup on them, the drivers side is worse, the one plug is full of buildup, I also unhooked my electric FP sensor and used a analog FP gauge and started the car the FP was steady at 46 and when i unplugged the vaccum it rose up to 50 but there wasent and fluxuiation as there is with the electric gauge, I dont know if its a bad sensor or if thats the way electric gauges work regardless the car is about 8 lbs to high at idle,. I dont have my parallel system ready to install yet so i guess im going to send my Computer back to PCM4less and have him check the FP settings.

 

What about your wires, are they OK? Also, I would check/replace you Coil...might not be getting the full juice and O2s