TigerFan187

iTrader: (1)

Dyno tune has a A/F switch/gauge that will monitor when you spray and if you run rich(higher than 12.5:1) or lean(lower than 14.5:1) it shuts off the n20. I really want this because thats some extra insurance. The reason I have ?'s is because 03GMC had a problem with it and what was happening was he was running to rich when he tried to spray and he couldnt spray at all. I have sent him a PM because he thought it was a probelm with the equipment and never posted what was wrong. I have a TNT F-1 kit and mods below so should I have a problem running to rich? I didnt even worry about ti untill someone told me that our trucks run rich normally and with the TNT kit I would be running really rich. Do I need to worry about running to rich to were I couldny use the A/F switch? Thanks!

O3GMC

I forgot to mension in my PM that I wasn't actually running too rich, it was the gauge that was reading too high. No matter where I tried splicing in the the o2 signal wires to the PCM, the voltage was about .3V too high.

I've had great experiences with lots of other Dynotune.org products

Chingon

iTrader: (1)

03GMC: So you wouldn't recommend that A/F ratio switch then?

O3GMC

Another thing I need to add is that the gauge itself wasn't wrong, because I used a regular volt meter and it read the same as the gauge.

So I would recommend the gauge only if you can find the right way to install it. I haven't read any posts on this site about people installing standard air/fuel gauges, and if they have the light up kind....it would probably just peg to rich at WOT and they would think they're running rich.....well this isn't the case.......I tried different power sources, different grounds, different o2 sensors, different places on the wire and nothing worked.....almost like the voltage right off the o2's isnt the same as what the PCM sees, like there is some voltage loss through the pcm connection or fuse center, I dont know.

Chingon

iTrader: (1)

Hmmm, I wonder if it's one of those things where it's just your truck since they all act differently. Would you be able to splice into one of the PCM wires that goes to the 02s or something to get the same reading as my EFI Live shows?
What could you do to offset that .3V ?

O3GMC

When I talked with dynotune they had never heard of my problem before, so it might have been something I overlooked or maybe it was just my truck, i have no idea. I belive the o2 signal wire goes from the sensor to the fuse center, and then to the PCM, so maybe there is another wire from the fuse center to pcm that you would tap into - unless its the same exact wire just run through the fust box. There might be a way to put a resistor or something like that inline with the signal wire to get the voltage down but it might be hard or impossible to get it right on the correct voltage.

Overall I dont think its really worth it as a narrow band a/f gauge, but the nitrous cutoff switch is definetly a nice safety feature.

TigerFan187

iTrader: (1)

My buddy who works at a chevy dealership said that the 02 sensors on our trucks arent accurate at all! Ok I was in the middle of typing this post and my buddy called me and talked me out of the A/F switch! What Ill do is get a digital A/F gauge and just manually monitor it! Im also gonn get the LS1 timing tuner so when I spray my timing will be retarded and help with detonation and it also acts as a window switch! That A/F switch sounded really cool and good insurance but I dont think it will owrk for me!

O3GMC

If you get the digital air/fuel gauge....you may be able to watch it and let off if your gradually leaning out, such as not enough fuel pressue, but if there is a sudden drop, like you are spraying a 100shot and the fuel solenoid doesn't open.....once you see it lean way out it will be too late I think. And IMO its pointless to get the dynotune a/f gauge w/o the switch.......if you have the same trouble I had, the gauge will read to high anyways. The a/f switch is just a small switch that goes inline with the gauge and the nitrous relay, it has nothing to do with the gauges reading of the o2's.

I would either do the gauge and a/f cutoff, or no gauge at all. Unless youre talking about some other digital a/f gauge?

TigerFan187

iTrader: (1)

Ok I just got a email from Dynotune ths morning and it is some good news! here is what it said!--------" They are out of stock right now becuse were doing a re-design. It no longer cuts if its rich because so many folks run pig rich!
We are trying to make a few other feature improvments to make it a bit simpler to hookup as well. Keep an eye on the webpage for a status.
So to answer your question, all the new units will not shut down the n2o it the o2 goes rich....

CHeers

Dan"


That is really all I wanted was for it to cut off at lean! So I will most likely be trying it out after all! Thanks for all you replies! So what do you think about the new design?

Chingon

iTrader: (1)

Well, if it reads richer than it actually is wouldn't that be bad? What I mean is, lets say you're running lean like 14.0:1, it will read richer in 03GMC's case right? So if you want it to cut off at 15.0:1 it won't cut off because it's reading richer like 13.0:1 or whatever.
The new design won't cut out when rich which is fine, but shouldn't you be more worried about the lean conditions?