Fellows----I am not trying to scare anyone here about fuel mods or blowing up you engine without them. All I'm trying to point out is that the fuel system of the 3.4 was designed for the engine to run naturally aspirated. When the engineer designed it a TRD supercharger was not the least bit on his mind. TRD, who didn't make the supercharger, decided that a small supercharger would market well to owners of this engine. They had a package put together, marketed, and didn't include any provisions for needed extra fuel. That was a mistake. Many people jumped on the chance to add extra power. The leanout problems and detonation problems started coming in right away. TRD denied this and other people like Gadget at URD started looking for solutions.

All you have to do is look at this logically. You simply cannot expect a stock fuel system to adequately keep up with power adders like the supercharger or a turbo system. I can't remember the exact numbers but TRD says the blower adds about 75 hp to the 3.4. Logic should tell you that if you add 75 hp worth of air you need 75 hp worth of fuel to go with it. You added the S/C to get the air. What have you added to get the fuel? Without the proper fuel needed things start getting too hot. Pistons get weak and melt or break ring lands. Heads running too hot crack usually between valve seats. Detonation can really tear up an engine and can go as far as snapping a connecting rod without you hearing the first "ping".

Have fun with your supercharger and your truck. Do your best to "balance" your system so you can have more fun and not worry about doing harm to your engine.

OK----off my box now

 

You cannot read open loop AFRs from the OBDII port. You can read closed loop fuel trims with a scan tool like the BR3 and your computer but not open loop AFRs.

 

www.urdusa.com

These guys carry the wideband units from Innovate and PLX plus a ton of other goodies for our trucks.

 

Very well said Dave...!!!!

If that doesn't sink in peoples heads, then I don't know what else will...???

 

I meant with a regular O2 sensor installed for the signal of course. I guess the a/f gauge would be more important if he had fuel mods and was tuning though.

 

Yeah, I understood what you meant and you are right, the autometer gauge will work and a lot of folks use them. The guys with the later model trucks just have to install another regular O2 sensor for it in front of the cats. I found that for tuning purposes though they are not accurate enough so since I was tuning my truck and intended to help others tune as well, I spent the extra bucks and went with the Innovate LM-1 wideband unit.

 

Oh, well what I was thinking is that you could read the emission values of the 02 (nox, co, etc. etc.). Then, with that in hand you could use a formula named "lambda" which will tell you your AFR very accurately. I read an article about it somewhere and it's genious, the formula is long but it makes sense and it works. It's definately too much work for a one time thing, I would rather install a custom AFR sensor and read my stuff that way, right at the headers.