I have my VE tables tuned pretty good
128/128 .
I had to turn up the PE fuel at rpm a lot, this is a supercharged car.
My question is that when I enabled the highway mode fueling the o2 sensor soon as the car reaches 56mph the o2 gose to less than 100mv.
My Highway mode fuel AFR is set to 14.9 at all Maps up to 60kpa then the AFR is 14.7
is this normal or do I have something set wrong, or is there a problem with my car.
Any help greatly apprieciated.

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Louis
Convertable
92 Z28 305tpi Auto w/Paxton, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,and much more.
http://www.lbsz28blown.cz28.com

 

The O2 sensor dropping low is normal when you invoke Highway Mode as you have leaned out the engine. In fact, you will notice the BLM go higher to indicate this leaning condition.

You can control the MAP value where Highway Mode disengages. I set mine to 73 kpa and I am using 17.6:1 on all values, except 60 kpa, where I reduce it to 17.2:1. I found that values higher to 17.6:1 makes the O2 sensor get REALLY low (like single digits) and gets too inaccurate.

Also, I found adding additional spark via the Highway Mode Spark Advance table useful in getting more "response" from the engine. I had to alter the actual code slightly, but you can make it work by setting the "bit" that indicates HMSA is working. I actually modified the code to use MPH as a enabling threshold (removing the 4th gear test...which did not work) and altered the code to use the RPM as a "disabling" threshold of 2,500 rpm. Works better than the stock code IMO.

I normally have 40-42* spark advance when running at 14.7:1 at part throttle 35-55 kpa and I added another 5* of Highway Mode Spark Advance. When Highway Mode engages, I am running 17.6:1 with 47* of spark advance. I am able to climb a 6% hill and remain in Highway Mode with no knock occurring.

Lastly, look at the "lock timers" for both Highway Mode and HMSA. I prefer to set them to 0 to keep it lock in Highway Mode. If you leave it at 10, every 60 seconds it will drop out of Highway Mode and disable itself for the amount of time in the timer.

The timer is not defined in TunerCat (yet), but you can set them yourself. Look at the 8D hac for the location of these timers. I cannot remember the exact address.

It definitely works and can save 10-20% on gas, depending on how lean you go and how much spark advance you add.

 

Not to be an *ss or anything but I thought the subject naming convention was being reserved for the tutorials?

James

 

OOPS... my mistake I was referring to a 7730 ecm with my question about highway mode fuel.

------------------
Louis
Convertable
92 Z28 305tpi Auto
1/4 at 13.23 @ 106.1mph w/Paxton 10psi, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9 camaro SS wheels, 285x40x17 tires,and much more.
http://www.lbsz28blown.cz28.com

 

I agree