I agree with 03SSLE, I would not have tampered with the CEL light, that could be a fail point in your emissions check.

ZZP also warns on their site that a high flow cat can cause a PO420 CEL condition, even though there is nothing wrong with the high flow cat. Honestly, I would not beat yourself up over it. I know someone who did NOT go for a performance CAT on his VW Golf and had a 420 error (he did the non-fouler trick so he could pass our local emissions check).

I would seriously consider doing the non-fouler trick, as it is cheaper then the PCM.

Here's the link to the ZZP PCM tune Amy mentioned:
ZZPerformance - ZZP 1.0 PCM #ZZ-10PCM

It looks like it will cost about $125+shipping (and you have to remember to select the option to delete the 420 code). Personally, that is a LOT of money JUST to delete the 420 code from the PCM when you can probably do the job cheaper with the non-fouler trick.

The other option is hit the 3800 forums looking for someone willing to help you out who has a tuner and can delete the code from the PCM. The DHP PowerTuner you can connect to unlimited vehicles with no fees (just what the guy with the tuner may ask). But the HP Tuner (which is a superior tuning tool) will require the user to pay credits to use it on different vehicles (I forget what those credits cost), so that is an additional fee on top of the fee a guy willing to tune may have to charge.

 

As of right now, I'm in the process of trying to clear all the codes. If successful, I am going to go thru the "cycle"mthen take it in.
The dude doing the test was surprised the light was not on, but didn't fail it because of that, he failed it for the code.ninwill make the light visible again (for my own use as well) and even if it passes, I want the zzp PCM upgraded. Hope it all turns out well...lol.. Wish me luck...mjclemm...

 

By chance, does anyone know the part number of the spark plug "Fouler" that's needed for the Monte? Thanks.. Mjc...

 

I'm going to have to attempt to do the same thing by the end of this month: battery check first, then spark plug non-fouler, then tune. But I also have o figure out how to get rid of the hard shifting problem. That too causes the CEL to go on. I'm not really in the mood to replace the entire tranny.

 

MJ, it's just a universal spark plug defouler, probably a different thread, but they should be able to help you... just ask for it when you get there, go home, screw the 02 into the defouler, then screw it into the bung and you're done.

Spark Plug Non-Fouler | AutoZone.com


did you pull the code yet? sounds like potential cat issue.

 

The fouler you need is for the older 13/16" (18mm) spark plugs. NAPA sells them under part #730-2442. If you don't have a NAPA near you, your local Autozone or O'Reilly should be able to cross reference that number into the brand they sell.

I bought one but didn't need to install it, but be aware that you will need to use a drill and remove some material from the bottom of it (on the inside) in order to have enough room to completely thread the O2 sensor into it without it bottoming out in the anti-fouler.

Edit: I dug around on the forum and found my original post about the anti-fouler. You can see in the pics what I'm talking about having to drill out a portion of the anti-fouler to get the O2 sensor to fit properly.

https://montecarloforum.com/forum/he...foulers-29498/ < Link

 

Hello, just did the Spark plug defouler, very easy, except I think I still managed to F it up !...lol... I was reading that you had to drill out the spark plug fouler to get the o2 to fit inside, it didn't seem to fit right after, so I drilled out the other one as well. Will this cause another problem? Both foulers drilled to 1/2" I swore that's what I read, but re reading it, it appears I read it all wrong, just the outside fouler gets drilled I think.. I may just have to buy another fouler kit and do it again. No biggie, but I'm not sure if both are to be drilled or not..... Help again !.. Lol... Man do I feel stupid.. AGAIN !

 

If you disconect the battery for 15 min then reconnect it drive for about 15 min hopefully befor the CEL comes on the sensors may have not had enough time to spit out any codes. My neihbor did it on his explorer. first time the sensor didnt boot up yet so he had to drive around for another few min.

 

MJC this is off topic but did you ever make that body kit for your front end? That would be a very marketable kit.

 

I think the only reason the outside fouler gets drilled is to simply fit the O2 probe. I honestly don't know if having both drilled will make a difference. If I wanted to avoid crawling under the car and doing this more then once, I'd just hit the store get another fouler.

Also, to PROVE if this resolved the problem at hand, I don't think I'd clear the codes, I'd drive it around a couple of days and see if the CEL de-activates itself (resulting in the failed condition no longer exists).