It gives the tube some length so that the O2 sensor doesn't pick up any ambient oxygen and give a false lean condition. It's coiled, I assume, so that it doesn't hang 10' off the back of the boat.lol
Eddie

It keeps fresh outside air from coming in contact with the sensor during the negative exhaust pulse.

On my first Sniffer my O2 sensor was only 3" from the aft end of the pipe. So during idle the engine was pulling outside air back into the pipe and causing a very lean reading (reversion).

Once I got above idle speed I was getting a reading but at idle i could not get a reading.

The curled up section is approx 3' long.

I like the way you have worded your response much better than mine!

I ran across a guy in the swap section with a Port side lightning header for sale at a very reasonable price. His starboard header was leaking. So I pulled the O2 bung out of my copper contraption and tig welded it into the header using Eddie Youngs method of using a ball peen hammer to crimp the inner and outer header tubes together. Worked beautiful! I now also understand why Lightning advises against welding on there Freshwater Headers. You are will basically expose raw mild steel to your water passage in the Header. If you have the Stainless inner and outer tube headers thats a different story.

Anyways took the boat out today with my O2 gauge hooked up and it worked perfectly. I was getting real good readings up until about 5 lbs. of boost. Above 5 lbs. of boost the motor started leaning out. I am running a stock 1997 502 Mag MPI with a M3sc Procharger. Stock injectors, Stock computer. MEFI 1 or 2 I am not sure which. Anyways I am at 80 lbs. of fuel pressure at 5 lbs. boost, AFR = 12.0. Once I get above 5 lbs. boost i start leaning out. I believe the problem is my fuel system is maxed out at 80 lbs. Tried jacking up the pressure and can not get more than 80 lbs. Wide open I get about 7 lbs. boost.

I think I know what needs to be done. Upgrade fuel system to keep up with the Procharger!

I don't think I want to jack up my fuel pressure any higher to richen up the top end. So I put in a call to Tyler Crockett and am dropping off my ECM tomorrow to be reprogrammed.

Nice to hear your sensor lives in that header, wish ours did ! lol

Yes, your fuel system is at its limits now. Remember just jacking up the fuel pressure is nothing but a band aid for not having a boost reference regulator and not enough fuel system.

You might want to look into larger injectors as well.

Thanks for the reply, I was starting to think I was talking to myself. I was able to position my sensor about 8" before the point water is introduced. I have the longer collectors.

I am still learning a lot about fuel injection and tuning. I pulled my ECM off of the motor tonite. I was surprised to see that it had an Arizona Speed & Marine sticker on the backside. Dated year 2000. I was unaware of the ECM being reprogrammed. The Mechanic that installed the Procharger for the original owner was also unaware.



Anyways I am going to stop by Tyler Crocketts shop tomorrow after work and have him take a look at it.

While I was tinkering with my motor I decide to pull off my fuel rail and bore out #7 injector hole. Glad I did. Take a look at what I found in the filter screens of my injectors!

I believe it is chunks of plastic from my Aeromotive fuel pump. I had an older style pump that was probably being attacked by the Ethanol in the fuel nowadays.[ATTACH=CONFIG]525069[/ATTACH][ATTACH=CONFIG]525070[/ATTACH][ATTACH=CONFIG]525071[/ATTACH]

damn....inside of a hose ??? what in a pump would that come from ?

Its hard to see but in the first picture that little green filter basket was completely full of the plastic chunks. 5 of my injectors were like this.

I have been told that the older Aeromotive fuel pumps were not ethanol resistant.

The ethanol would attack the plastic in the pump. Possibly the windings on the motor?